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1 AN ANALYSIS OF SMALL FARMER MANAGEMENT OF AMAZONIAN DARK EARTH ON THE UCAYALI RIVER IN PERU By ELIZABETH L. GREGG A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIR EMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2013
2 2013 Elizabeth L. Gregg
3 To my adviser Dr. Peter Hildebrand who has always be en an advocate for his students
4 ACKNOWLEDGMENTS I would like to thank my adviser Dr. Pet er Hildebrand for giving me the opportunity to pursue my interests and guiding me each step of the way. Additionally, I would like to thank my committee members Dr. Nigel Smith and Dr. Ken Buhr for their advice and support. A great deal of gratitude goes o ut to my mother and father for their emotional support and un wavering confidence in my abilities. Significant logistical support was received fro m IIAP in Pucallpa and for that I will be eternally grateful to Mr. Jose Sanchez Choy. My guide Rafael Urquia Odicio was also an integral part of this study, and I would like to thank him for his incredible knowledge of plants and the ability to garner support and participation from community members. I would like to thank the Mu oz Augustine family for opening t heir home to me and offering kind words of encouragement when things were difficult I appreciate the logistical support of Roldan Mu oz Augustine and Betty Mu oz Augustine who assisted me in making contacts with key member s of the community. I would like to thank the Universidad La Molina for analyzing my soil samples and Alfredo Rios for helping me obtain information on the laboratory methods. I owe my gratitude to Melissa Pisaroglo Carvalho for checking my statistical analyses. I would also like to than k the Tropical Conservation and Development group of the University of Florida for funding support, as well as the Sc h ool of Natural Resources and Environment.
5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ .......... 8 LIST OF ABBREVIATIONS ................................ ................................ ............................. 9 ABSTRACT ................................ ................................ ................................ ................... 10 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 12 An Overview of Amazonian Dark Earth ................................ ................................ ... 12 Characteristics of Amazonian Dark Earth ................................ ............................... 13 A Brief History of the Discovery of ADE ................................ ................................ .. 15 Prior Research of Land Use Systems on ADE in the Brazilian Amazon ................. 17 Annual Crops ................................ ................................ ................................ .... 18 Manioc ................................ ................................ ................................ .............. 19 Agroforestry ................................ ................................ ................................ ...... 20 Home Gardens ................................ ................................ ................................ 21 Pasture ................................ ................................ ................................ ............. 22 Typical Agricultural Practices in the Peruvian Amazon ................................ ........... 23 Project Outlines ................................ ................................ ................................ ...... 24 Project Goals ................................ ................................ ................................ .... 24 Research Questions and Hypotheses ................................ .............................. 24 Changes to Original Research Questions ................................ ........................ 25 Research Design and Methods ................................ ................................ ............... 26 Site Selection ................................ ................................ ................................ ... 26 Sampling ................................ ................................ ................................ .......... 27 D ata Collection ................................ ................................ ................................ 27 Data Analysis ................................ ................................ ................................ ... 29 Background Information on the Study Area ................................ ............................ 29 The Cultural Sequence of the Central Ucayali Region ................................ ............ 30 2 CONTEMPORARY AGRICULTURAL USE OF AMAZONIAN DARK EARTH IN THE UCAYALI REGION OF PERU ................................ ................................ ........ 33 Land Use Methods on ADE ................................ ................................ .................... 33 Management Practices of Home Gardens on ADE and Non ADE Soil ................... 36 3 SPEC IES DIVERSITY OF ADE HOME GARDENS ................................ ................ 39
6 Agrobiodiversity ................................ ................................ ................................ ...... 39 A Comparison of Native and Non Native Crops ................................ ...................... 42 Prevalence of Typical Floodplain Crops in ADE Home Gardens ............................ 47 4 A SOIL ANALYSIS OF ADE AND NON ADE SITES IN THE CENTRAL UCAYALI ................................ ................................ ................................ ................ 50 An Overview of Dominant Soil Types in the Central Ucayali Region and Their Characteristics ................................ ................................ ................................ ..... 50 Soil Textural Analysis ................................ ................................ .............................. 51 Soil Organic Matter Content of ADE and Non ADE Soil Samples .......................... 53 A Comparison of Cation Exchange Capacity (CEC) in ADE and Non ADE Soil Samples ................................ ................................ ................................ ............... 54 A Comparison of pH in ADE and Non ADE Soil Samples ................................ ....... 55 Nitrogen, Phosphorus and Potassium Levels in ADE and Non ADE Soil Samples ................................ ................................ ................................ ............... 56 Exchangeable Cations in ADE and Non ADE Soil Samples ................................ ... 59 Micronutrients in ADE and Non ADE Soil Samples ................................ ................ 61 5 CONCLUSIONS ................................ ................................ ................................ ..... 64 APPENDIX A SPECIES LISTS FOR ALL HOME GARDENS SURVEYED ................................ .. 69 B SOIL SAMPLE ANALYS ES ................................ ................................ .................... 90 C STATISTICAL ANALYSES ................................ ................................ ..................... 94 LIST OF REFERENCES ................................ ................................ ............................... 95 BIOGRAPHIC AL SKETCH ................................ ................................ .......................... 100
7 LIST OF TABLES Table page 1 1 Species commonly p lanted on ADE in various land use systems ....................... 17 1 2 Crops cultivated in 126 annual fields on ADE at 13 communities in the municipality of Manicor, middle Madeira River, Brazil, in 2008. ........................ 19 1 3 Cultural sequence of th e Central Ucayali region with radio carbon dates ........... 31 2 1 Locations and land uses of all sites encountered ................................ ............... 33 3 1 Number of occurr ences and relative frequencies of all species encountered in both ADE and non ADE home gardens ................................ ......................... 43 4 1 Textural classes of ADE soil samples collected and relative percentages of sand, silt and clay. ................................ ................................ .............................. 52 4 2 Textural classes of n on ADE soil samples collected and relative percentages of sand, silt and clay. ................................ ................................ .......................... 52 4 3 Percent s oil organic matter for ADE and n on ADE soil samples ........................ 54 4 4 Cation exchange capacity for ADE and n on ADE soil samples .......................... 55
8 LIST OF FIGURES Figure page 1 1 Location of Project Sites in the Department of Ucayali, Peru. ............................ 26 3 1 Examples of home garden structure an d composition i n the study area ............ 40 3 2 Relative frequency of non native species that were more prevalent in ADE home gardens. ................................ ................................ ................................ .... 46 3 3 Relative f requencies of typical floodplain crops that were more common in ADE home gardens. ................................ ................................ ........................... 48
9 LIST OF ABBREVIATION S ADE Amazonian Dark Earth CEC Cation exchange capacity NPP Net primary productivity SOM Soil organic matter
10 Abs tract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science AN ANALYSIS OF SMALL FARMER MANAGEMENT OF AMAZONIAN DARK EARTH ON THE UCAYALI RIV ER IN PERU By Elizabeth L. Gregg May 2013 Chair: Dr. Peter Hildebrand Major: Interdisciplinary Ecology Amazonian Dark Earth (ADE) is an anthropogenic soil that occurs in pockets throughout the Amazon and has been regarded as having higher fertility tha n natural Amazonian soils. Information gleaned from the study of these high charcoal soils can be applied to research in modern biochar technology. This research addresses the current management practices on ADE soil and provides a comparison of ADE and no n ADE home gardens, which represent the most prevalent form of use in the Central Ucayali region. While the overall agrobiodiversity of ADE and non ADE home gardens did not differ significantly, and the prevalence of non native species was not significantl y higher, there was a greater proportion of typical floodplain crops found in ADE home gardens. Soil samples were collected and analyzed from both ADE and non ADE home gardens to determine if differences in fertility contribute to different species composi tion. While most ADE studies attribute the greater fertility to an increase in cation exchange capacity (CEC), this study found that the CEC was not significantly higher in ADE home gardens. However, other important fertility factors such as pH, organic ma tter content phosphorus, potassium manganese and calcium were significantly higher in ADE home gardens. While most studies on the use of ADE have been in the Brazilian Amazon, t he
11 data presented in this study provide unique information about ADE use and fertility differences in the Peruvian Amazon.
12 CHAPTER 1 INTRODUCTION An Overview of Amazonian Dark Earth Most upland Amazonian soils have been regarded as unsuitab le for agriculture and often lo se fertility quickly when cultivated intens iv ely. However, scattered throughout the uplands of the Amazon Basin are patches of dark fertile soil Amazonian Dark Earth (ADE), which were created 500 2500 years ago by Amerindian populations (Lehmann et al. 2003). ADE comes in two distinct forms. The darker form, kn own as terra preta, likely developed from pre European village refuse and contains high concentrations of potsherds and charcoal. The lighter form, referred to as terra mulata, is largely devoid of potsherds and believed to be the product of intensive cult ivation burn (Denevan 2004 ; Fraser and Clement 2008 ). However, ADE soils exist as a continuum of black to light grey or brown, and distinguishing the two varieties is of ten quite difficult without extensive excavations. For this reason the broader term of ADE was adopted rather than simply terra preta Schmidt (2010) found continued anthrosol formation in a Kuikuru village on the Xingu River in Brazil through the use of middens and small fires. These areas were valued for their fertility and fruit trees were often planted atop older middens (Schmidt 2010). Regardless of whether or not these ancient fertile soils were intentionally created for improving agricultural produ ctivity or whether they are an accidental byproduct of habitation, they offer a unique opportunity to study the potential of charcoal amendments to increase fertility on highly weathered, trop ical soils. Though there is interest in the use of biochar in ag riculture, there has been relatively little research
13 regarding the use of these ancient charcoal amended soils The majority of research regarding modern agricultural use of ADE has been carried out in the Brazilian Amazon where oxisols are the dominant so il type and little is known about the existence or uses of ADE in the Peruvian Amazon where ultisols are more common This research seeks to address the gap in knowledge regarding agricultural practices on ADE soil in the Ucayali region of the Peruvian Ama zon. Characteristics of Amazonian Dark Earth Numerous studies have noted that ADE is often recognized by local inhabitants as highly fertile, and is sought after by farmers ( Fraser et al. 2009; Hiraoka et al. 2003; Smith 1980). This high regard of ADE has created an interest within the agricultural research community regarding the potential benefits of charcoal (biochar) as a modern agricultural soil amendment. Though ADE was created with far greater inputs than simply biochar, it seems that this compo nent is likely responsible for the relative stability and long term fertility of ADE (Lehmann and Joseph 2009). Schmidt (2010) found that habitation due to a variety of input s including food waste, weed biomass, discarded construction materials, human and animal manures and charcoal and ash from fires. A n cient ADE soils are undoubtedly formed with far greater inputs than charcoal alone. Yet, biochar can give the soil its dark colo r, improve soil structure, aggregation, water infiltration and retention, and nutrient storage capacity (Lehmann et al. 2003). Though most charcoal supplies few nutrients, it does help to retain those present as well as those added in the form of fer tilizers due to an increase in the cation exchange capacity (CEC) It also induces an incre ase in pH which leads to lower a luminum (Al) toxicity. ADE contains elevated levels of phosphorus (P), calcium (Ca), magnesium
14 (Mg), manganese (Mn) and zinc (Zn), a s well as, increased microbial biomass and diversity (Lehmann et al. 2003). However, there is more knowledge to be gleaned from ADE beyond its physical and chemical properties. Investigating current agricultural management techniques on ADE is critical to understanding the role that biochar may be able to play in fertility management and sustainable agricultural practices on smallholder farms in the tropics. The primary users of ADE are smallholder farmers, and agriculture on ADE often follows a similar p attern to swidden fallow agriculture ( Hiraoka et al. 2003). However, length of use is often extended bec ause of higher nutrient content and fallow periods are often decreased due to the rapid fertility regeneration of ADE soil under secondary growth (Leh mann et al. 2003). Through farmer interviews, German (2003) found that farmers also perceive that closed fallow or mature secondary forest, regenerates fas ter on ADE than on the typical o xisols of the terra firme in the Brazilian Amazon This rapid grow th and restoration of fertility might be due to an increase in the rate of biological nitrogen fixation induced by the charcoal present. In a biochar study by Rondon et al. (2007) it was found that charcoal addition increased biological nitrogen fixation b y over 20% in Phaseolus vulgaris This is likely due to the increase in molybdenum availability in the presence of biochar, because molybdenum is necessary for the formation of nitrogenase which catalyzes biological nitrogen fixation ( Rondon et al. 2007). Because of the high charcoal content of ADE, biological nitrogen fixation may be occurring more rapidly on these soil s so nitrogen may accumulate faster during fallow periods increasing the amount of biomass produced. German (2003) noted that ADE farmers acknowledge a greater importance of incorporating organic matter into the
15 soil than non ADE farmers. Additionally, they recognized the importance of crop rotations for restoring the fertility of ADE soil (German 2003). A Brief History of the Discovery of ADE Though large indigenous settlements had been documented by explorers such as and Pedro Cristoval de Acua, the Jes uit Priest who documented the Amazon voy age of Pedro Texeira in 1639 i nitial explo ration of ADE sites began in the 1870s with the expeditions of Charles F. Hartt, a young Canadian geologist, who was primarily interested in the geology and archaeological remains associated with these ADE sites (Kawa 2008 ; Hartt 1874 ). However, some con sider the Brazilian scholar Ferreira Penna to be one of the first Amazonian archaeologists ( Kawa 2008 ). He surveyed numerous archaeological sites and wrote about archaeology and ethnology of the Amazon region. Both scholars identified these ADE sites as a rtifacts of human habitation though the fertility and methods of creation were little understood (Kawa 2008). students Herbert Smith (Smith 1879) After visiting a sugar cane field near Taperinha he noted: The cane field itself is a splendid sight; the stalks ten feet high in many the best on the Amazons. It is a fine, dark loam, a foot, and oft en two feet, thick. Strewn over it everywhere we find fragments of Indian pottery, so abundant in some places that they almos t cover the ground. (Smith 1879 : 144) During the same era, ADE was being investigated by the geologists C. Barrington Brown and William Lidstone These geologists were actually the first to describe the soil Brown and Lidstone
16 1878; Woods and Devenan 2007). Later in the early 1900s, the first soil analysis of ADE wa s conducted by the German geologist Friedrick Katzer ( Katzer 1903; Woods 2003). Another influential explore r of ADE sites was Curt Unkel Ni muendaj documented ADE soil in 65 locations in Brazil during his explorations fro m 1923 1925 (Kawa 2008; Ni 2004). Like other investigators before his time, he stated numerous reasons why ADE w as formed by indigenous peoples (Nimuendaj 2004). In the 1940s, doubts about the carrying capacity of the Amazonian environment brought into question the possi bility that ADE could have been created by large permanent environment on this scale According (Steward 1946 1959), it was stated t hat small, dispersed, and impermanent settlements were the primary characteristics of Amazonian societies. Betty Meggers later became a key supporter of this model, arguing that given envi ronmental constraints it was not possible for Pre Columbian populat ions to develop la rge complex societies ( Meggers 1996) number of researchers still supported the early hypothesis that these soils were created by human habitation. Wim So mbroek even proposed that the areas of lighter ADE referred to as terra mulata were ancient agricultural fields (Sombroek 1966). Yet it was not until the 1980 Carrying Capacity in Amaz that this human link to Amazonian Dark Earth again began to be accepted in the scientific community (Smith 1980; Woods and Denevan
17 2007). Though it is now generally accepted that ADE is of anthropic origin, it is still widely debated as to exactly how these soils were formed and what the primary inputs were. Though the debate over intentionality continues, it is unlikely that research will definitively determine the exact intentions of the ancient inhabitants of ADE sties. As such, many researchers have now turned their focus to the modern use of ADE soil and the potential benefits of the use of charcoal in agricultural soils. These pockets of dark fertile soils scattered throughout a region largely devoid of agricultural potential offer a unique op portunity to compare agricultural practices depending upon soil constrain t s or opportunities. This study will provide further information on the modern management of ADE soil in an area that has received little attention in this regard. Prior Research of L and Use Systems on ADE in the Brazilian Amazon Modern l and use systems on ADE cover a wide variety of methods, and a high diversity of crops are employed (Table 1 1 ). The most common cropping systems found in the Brazilian Amazon include manioc gardens, an nual cropping, home gardens, agroforestry and occasional use for pastures (Hiraoka et al. 2003; Kawa 2008; Fras er et al. 2011; Kawa et al. 2011). Table 1 1 Species Commonly Planted on ADE in various land use systems Common Nam e Scientific Name Annuals Manioc Manihot esculenta Maize Zea mays Beans Phaseolus vulgaris Watermelon Citrullus lanatus West Indian Gherkin Cucumis anguria Pineapple Anannas comosus Squash Cucurbita spp. Peppers Capsicum spp. Tomatoes Ly copersicon esculentum (Sources: Fraser 2011; Kawa 2008; Hiraoka et al. 2003)
18 Table 1 1: Continued Common Name Scientific Name Perennials Coffee Coffea spp. Cupuau Theobroma grandiflorum Cacao Theobroma cacao Rubber Hevea brasiliensis Bra zil Nut Bertholletia excelsa Avocado Persea americana Papaya Carica papaya Banana a nd Plantain Musa spp. Orange Citrus sinensis Breadfruit Artocarpus altilis Mango Mangifera indica Malay Apple Syzygium malaccense Inga Inga spp. Aa Eute rpe precatoria Bacaba Oenocarpus mapora Tucum Astrocaryum aculeatum Mucaja Acrocomia aculeate um Buruti Mauritia flexuosa Peach Palm Bactris gasipaes Coconut Cocos nucifera Oil Palm Elaeis oleifera (Sources: Fraser 2011; Kawa 2008; Hiraok a et al 2003) Ann ual C rops Because of the m arked increase in fertility of ADE over typical Amazonian upland soil, these areas are often preferred by small farmers for the production of nutrient demanding market crops (Hiraoka et al 2003). Introduced plants that only yield well in fertile soils, such as watermelon ( Citrullus lanatus ), papaya ( Carica papaya ), maize ( Zea mays ), beans ( Phaseolus vulgaris ), West Indian gherkin ( Cucumis anguria ), and squash ( Cucurbita spp.), are often preferentially cultiva ted on ADE soil ( Fraser 2010). The prevalence of different annual crops on ADE in Manicor is outlined in Table 1 2.
19 Table 1 2. Crops cultivated in 126 annual fields on ADE at 13 communities in the municipality of Manicor, middle Madeira River, Braz il, in 2008. Plant Number of annual fields % of total Bitter m anioc 81 64.3 Maize 14 11.1 Watermelon 12 9.5 Beans 4 3.2 Bitter manioc and maize 4 3.2 Sweet m anioc 3 2.4 Maize and beans 3 2.4 Maize and sweet manioc 2 1.6 Diverse mixed crops 1 0.8 Pasture 2 1.6 Total 126 100 (Source: Fraser et al. 2011) However, crop choices and agricultural methods are also dependent on access to markets. Farmers with ADE soil and difficult market access often prefer to grow staple crops which store well, su ch as manioc (Kawa et al. 2011). When ADE farmers with better market access are oriented toward commercial production they sometimes employ methods such as monocropping, irrigation, pesticide use, mechanized tilling and fertilizers, much the same as comme rcial production on non ADE soils (Major et al. 2003). Manioc A study by Fraser et al. ( 2009 ) in Manicor on the middle Madeira River found that the most prevalent crop on ADE was bitter manioc ( Manihot esculenta ), which was cultivated in 64% of annual A DE plots. However, another study on the Madeira River in Borba by Kawa (2008) found that only 37.5% of ADE plots contained manioc in contrast to 92.3% of plots on non ADE o xisols. The most likely explanation for the discrepancies
20 between Manicor and Bor ba is the greater market access in Borba ( Fraser et al. 2011), which has lead to a greater prevalence of market crop production on ADE. The efficiency of bitter manioc production on ADE is still debated, as German (2003) note that while vegetative growth is vigorous, tuber yield is not significantly increased. Yet, in the middle Madeira Fraser (2010) states that the farmers are aware of the advantages of manioc cultivation on ADE, such as faster maturation and larger yields. He further suggests that certa in manioc landraces may have been intentionally selected for ADE use in areas that have been farmed for many years. Thus, the choice to plant manioc on ADE may also be dependent upon the historical ecology of the location and the knowledge of manioc landra ces within the community. Agroforestry Agroforests have been an integral part of Amazonian habitation throughout history and are documented archeologically and historically. These historical anthropic forests were created by encouraging a variety of both domestic and wild species through both direct planting and haphazard discarding of seeds. Agroforestry in the Amazon includes such systems as mature agroforests, home gardens forest enrichment and managed fallows ( Smith et al. 1998). In the middle Amazon mature agroforests are often established from manioc fields or kitchen gardens (Hiraoka et al. 2003). The establishment of agroforests from manioc gardens occurs in three phases (Hiraoka et al. 2003 ). The first phase generally lasting one year involve s the planting of manioc and intercropping wi th longer cycled perennials that helps to suppress wee ds. The second stage occurs in two to three years from planting and initially involves a second planting of manioc with species such as banana, cashew, pine apple, papaya
21 and various palms, which cast shade at different levels on the emerging long cycled species (Hiraoka et al. 2003 ). A tall and densely shaded agroforest begins to dominate six or seven years after planting and is characterized by species such as coffee ( Coffea spp), cacao ( Theobroma cacao ), cupuau ( Theobroma grandiflorum ), buruti ( Mauritia flexuosa ), tucuma au ( Astrocaryum aculeatum ) B razil nut ( Bertholletia excelsa ), breadfruit ( Artocarpus altilis ), mucaj ( Acrocomia aculeate um ) and rubber ( Hevea brasiliensis ) (Hiraoka et al. 2003). Hiraoka et al. ( 2003 ) found that small farmers preferred ADE for agroforests on the Middle Amazon. The litter fall and shade from multi storied canopies can out compete weeds which are a major problem in the c ultivation of ADE sites (Major et al. 2003). These species rich plots can provide food, fiber, firewood, medicine, timber and habitat for native and domestic wildlife. The economic function of agroforests varies in relation to market size and accessibilit y (Hiraoka et al. 2003). Areas that are fa rther from large urban centers generally use agroforestry products in the home, while agroforests in peri urban areas are often specialized in a limited number of economically valuable crops (Hiraoka et al. 2003) Because market forces limit the number of commercially viable species, commercial agroforests typically contain two to six species of trees and shrubs (Smith et al. 1998). The primary differences between agroforestry on ADE and non ADE plots are species richness and composition. Species that would normally be limited to rich floodplain soils can also thrive on ADE due to the increased nutrient content and water retention capacity (Hiraoka et al. 2003). Home G ardens Home gardens are a form of agroforestr y defined by Nair et al. (2008) as
22 area surrounding the residence, are an integral part of Amazonian habitation, and are designed to provide various foods and other product s for the household (Nair et al. 2008). Home gardens are extremely diverse, and can act as a significant reservoir for agrobiodiversity (Smith et al. 1998). Fraser et al. ( 2011) found species diversity and plant density to be greater in home gardens on ADE plots. Dominant woody perenials in home gardens on Oxisols in the Brazilian Amazon are coffee ( Coffea spp), Brazil nut ( Bertholletia excelsa ), cupuau ( Theobroma grandiflo rum ), rubber ( Hevea brasiliensis ), and the aa ( Euterpe precatoria ), bacaba ( Oenocarpus bacaba ), and tucum ( Astrocaryum aculeatum ) palms ( Fraser et al. 2011). ADE home gardens also include species such as, avocado ( Persea americana ), papaya ( Carica papa ya ), plantain and banana ( Musa spp), cacao ( Theobroma cacao ) and orange ( Citrus sinensis ), which are often less productive on natural terra firme soils. ADE home gardens were also found to contain more Meso American exotics that are not tolerant of floodpl ain conditions ( Fraser et al. 2011). In Borba and in Manicor there was a significant increase in the number of exotic species found in home gardens on ADE (Kawa 2008; Fraser et al. 2011). Pasture Though ADE is used occasionally for pastures, it is not a preferred land use. Hiraoka et al. ( 2003 ) note that, cattle ranching in the middle Amazon is primarily practiced in t he floodplains with cattle spending only 4 5 months on the uplands, which are seen primarily as temporary flood season refuges. The prima ry grass species used in Amazonian pastures are kikuyu grass ( Brachiaria humidicola ) and b raquiar o ( Brachiaria brizantha ) and pasture management generally consists of annual weed
23 control through burning (Hiraoka et al. 2003). Because of the more vigorous weed growth on ADE, pastures on these soils are often seen as a nuisance due to the increase in labor required to control weeds (Hiraoka et al. 2003). Typical Agricultural Practices in the Peruvian Amazon The typical method of agriculture practiced in the Amazonian uplands today is swidden fallow or sla sh and burn agriculture (Coomes 2000). This method of clearing and burning natural vegetation delivers a pulse of nutrients from the vegetation to the soil yet these nutrients are exhausted in a few year s of intensive cultivation and the land must then be left fallow (Nortcliff 1989). However, fallow plots also have benefits for the livelihood of small farmers, as a variety of useful products including timber, firewood, construction materials, fruits and medicinal plants are often encouraged to grow and subsequently collected from secondary growth forests (Coomes 2000). Increasing population pressure and sedentary habitation in the Amazon are causing the fallow period to be decreased in some areas resul ting in greater soil degradation and more area being cleared, increasing th e rate of deforestation (Coomes 2000; Nortcli ff 1989). Also of great importance in the Peruvian Amazon is floodplain a griculture. M any floodplain forests have been cleared to pl ant crops including manioc, maize, plantains watermelon, beans, peanuts, sugarcane, rice and various fruit trees (Goulding et al. 2003). The young alluvial soils of the active floodplain are more fertile than the upland terra firme soils (Lathrap 1968 ). This method of agriculture is perhaps more important in the upper Amazon than lower because the nutrient quality of the riverine sediments is greater closer to the Andes (Zarin 1999). Zarin (1999) explains that this gradient of fertility is due to diluti on of the concentration of Andean sediments in the river, the weathering of cations in the journey down river and capture and biological uptake of
24 cations by riverine vegetation. Floodplain agriculture is inherently seasonal and often risky with the unpre dictability of river dynamics. Yet it plays an important role in agricultural production in the Ucayali region. Project Outlines Project G oals Relatively little is known about ADE sites in the Peruvian Amazon and even less about its modern agricultural u ses. This research investigates the relative fertility of ADE soil compared to the native ultisols and explores the current management practices of ADE agriculture in the Peruvian Amazon. It provides insight into agrobiodiversity of home gardens on ADE and non ADE soil and how floral composition can vary depending on soil type. This study also provides a comparison to other studies of ADE use in the Brazilian Amazon. Research Questions and Hypotheses The main question s guiding my research are : How are farm ing practices and crop choices different on ADE and non ADE soils? How does plant diversity and fertility vary between ADE and non ADE soils? (1) Are farmers more likely to plant market oriented crops when ADE is available, or is crop choice dependent pr imarily on access to markets rather than availability of high er fertility soil? Hypothesis: Farmers with both market access and access to ADE soil will use it to produce nutrient demanding market crops. Farmers without access to markets will likely use AD E for the production of staple crops for home consumption such as manioc. (2) How are farmers managing the fertility of ADE soil? Are these practices sustainable even when nutrient demanding market crops are being grown? Are farmers using pesticides and sy nthetic fertilizers or crop rotations and organic soil amendments on ADE? How do these management strategies differ from those on adjacent non ADE soils?
25 Hypothesis : Use of ADE will not necessarily lead to more sustainable farming practices. External input s such as fertilizers and pesticides will still be increased when nutrient demanding market crops and non native crops are grown on ADE soil. (3) Is ADE soil preferred for annual cropping or perennial agroforestry systems? If agroforestry is preferred, ar e nitrogen fixing trees being used for fertility or are the primary tree species those with economic value? Hypothesis: Agroforestry systems such as fruit tree production will be preferred over annu al cropping, because of the increase in weed pressure due to the frequent soil disturbance of short term annual cropping systems. Because of the increased fertility of ADE, trees favored for agroforestry systems will have economic or household uses as opposed to fertility management purposes (4) How drastically does the fertility of ADE home gardens differ from the fertility of non ADE home gardens? Hypothesis : Fertility of the soil will be higher than typical Amazonian soils and a higher pH and cation exchange capacity will be observed for ADE samples (5) Is th e plant diversity higher in ADE home gardens ? Hypothesis: Plant diversity will be higher on ADE soil because species from both the uplands and floodplains will thrive on the higher fertility of ADE. (6) How does the species composition compare between AD E and non ADE home gardens ? Hypothesis : Home gardens on ADE will have more floodplain species as well as more non native species. Changes to Original Research Questions The design of this research relied heavily on similar studies conducted in the Brazil ian Amazon. Yet as can be expected, the reality of this region differed drastically from the Brazilian studies The original research design was focus ed primarily on the chacra system of annual agriculture. However the primary land use system observed on A DE soil was the home garden s ystem a form of agroforestry. Because home garden products are largely for use in the home, the first research question on market orientation does not apply and will not be addressed by this study. In addition research
26 questio ns 4, 5 and 6 were added to provide greater insight into the fertility, agrobiodiversity and composition of ADE and non ADE home gardens. Research Design and Methods Si te S election The Ucayali region in the Peruvian Amazon was selected for this research b ecause very little is known about t he management of ADE in this region. The majority of ADE management research has taken place in the Brazilian Amazon and as such, this study provides a unique opportunity for comparison of ADE management within a wider ge ographical area. The main study area, San Francisco de Yarinacocha was archaeologically documented by Donald Lathrap in the 1960s. The other two areas, San Rafael and Limong ema, were previously undocumented ADE sites (Figure 1 1 ) Figure 1 1. Location of Project Sites in the Department of Ucayali, Peru. ADE was found in these areas through communications with local inhabitants, soil probes and searches for ceramic fragments. San Francisco is located just outside of the
27 larger port city of Pucallpa and is connected both by road and waterways, while San Rafael and Limonjema are 5 and 3 hours by boat respectively from Pucallpa Sampling Gaining participation of residents in close knit native communities can often be an impediment in field research. To facil itate participation the Jefe of each community was contacted upon arrival for permission to work in the community and to gain preliminary information and connections. Randomized sampling was not an appropriate strategy for this research because most partic ipants were only willing to be involved in the research if introduced to the researcher by another community member. As such, a snowball sampling (also known as referral sampling) te chnique was employed to encourage participation in the research (Bernard 2006). Another impediment to participation was the language barrier, as most of the communities investigated were native Shipibo communities. Though nearly all Shipibos speak Spanish, as well as Shipibo, many of the elder community members were reluctant to participate in Spanish. To facilitate greater participation a native Shipibo guide was employed to translate from Shipibo to Spanish and to help foster trust among participants. The guide wa s recommended by the Instituto de Investigaciones de la Amazon a Peruana (IIAP) and his assistance proved to be invaluable in making contact and encouraging people to participate. Data C ollection Data concerning management practices of ADE soil were collected through semi structured interviews. The same interviews we re also conducted for a number of non ADE home gardens to provide a comparison of management practices. Extensive notes were taken and interviews were not recorded as many participants seemed reluctant to
28 speak when the tape recorder was on. Species lists were generated for all sites by touring home gardens and asking residents to identify the plants they had incorporated. Significant assistance was also obtained from the guide who had extensive ethnobotanical knowledge. In addition to interview data, soi l samples were collected and compared using the Munsell color system to determine whether or not the sites were ADE. The presence of ceramic fragments was also used to identify ADE sites. Often when participants were asked if there were ceramic fragments p resent in the soil one of the family members would quickly be able to identify a site of ceramic fragments. The depth of the deposit was first investigated by inserting the p robe to the maximum depth of 40 cm. The majority of ADE sites were found to extend beyond this depth and all samples used in this study came from sites which were greater than 20cm deep. Soil cores were collected to a standard depth of 20cm. The cores were collected from multiple sites throughout the garden in a semi random pattern avoi ding large trees and densely pattern was determined by the researcher to attempt to get a sample that was representative of the entire garden. The garden size was estimated by pacing the boundaries when possible. Once soil samples were collected they were screened with a cm mesh to remove large roots and any potential ceramic fragments and then they were dried. Soil sample s were labeled and packaged in plastic bags to be shipped to Lima. Soil analys es were sis de Suel os, Plantas, Aguas y Fertilizan tes at the Universidad La Molina in Lima. No soil samples were transported
29 outside of Peru. The characteristics analyzed at the laboratory included macronutrients, micronutrient s, cation exchange capacity, soil texture and pH Data Analysis Soil sample data between ADE and non ADE soils were compared by calculating average values and standard deviations for each facet of the soil analysis. Statistical significance of these values was investigated by calculating P v alues by performing T tests. One of the soil sample results in the non ADE group was anomalously high in all aspects of soil fertility ( sample number NE 25) despite the fact that it was located very close to another sample area that showed very poor fertility (sample number NE 23). Management practices did not differ widely between these two plots and the soil color and texture appeared similar. Because of the possibility for lab e rrors, this sample was omitted from the analysis. Species composition of the ADE and non ADE home gardens was investigated by calculating the relative frequency of each species as a percent of the total number of gardens. Certain species such as exotics a nd floodplain species were focused on to determine if the composition of ADE and non ADE home gardens varied. The relative frequencies of the exotic species were calculated and compared between ADE and non ADE home gardens. Background Information on the Study Area The Ucayali river basin occupies 4.9% of the total 6.8 million square kilometers of the Amazon Basin and is considered to be the main headwater tributary ( Goulding et al. 2003). The dominant soil types in the Central Ucayali are Ultisols, Ince ptisols and some Oxisols west of the Ucayali River ( USDA NRCS, 1999 ). The upland soils of the study areas were all mapped as Ultisols The study area is located in the department of
30 Ucayali and the largest port city is Pucallpa, which lies at approximately 300m elevation. The average annual rainfall in Pucallpa is 2,200mm (Goulding et al. 2003). Pucallpa is one of the few areas in the Ucayali Department that is connected to Lima by road. Though it has been connected since the 1940s, significant growth in Pucallpa did not occur until the 1980s (Goulding et al. 2003). The three main study areas were San Francisco de Yarinacocha and the surrounding vicinity, San Rafael near Masisea and Limongema. Of the three areas, San Francisco de Yarinacocha has the bes t access from Pucallpa and is the most densely populated with 110 families documented by the Centro Cu ltural de Jos Po Aza The same study documented 7 families in San Rafael and 12 families in Limongema. Though San Rafael was indeed a small community th is count seems somewhat low based upon the observations of the researcher. The Cultural S equence of the Central Ucayali Region The most extensive archaeological investigations of the Central Ucayali region were completed by Donald Lathrap in the 1950s an d 1960s. He documented 12 distinct waves of migration into the area over a period of 3,000 4,000 years through archaeological investigations and ceramic analysis ( Lathrap 1968 ). The cultural sequence and associated radiocarbon dates where available are pr esented in Table 1 3 These data were derived largely from excavations in San Francisco de Yarinacocha, one of the key sites investigated in this study. The current inhabitants of San Francisco, San Rafael and Limongema are all Shipibo natives and represen t the last wave of migration into the area. In this study, it was discovered that all of the villages investigated were situated, at least in part, on these ancient ADE sites.
31 Table 1 3 Cultural sequence of the Central Ucayali region with radio carbon dat es Occupation Radio carbon dates Shipibo Conibo to present Caimito A.D. 1320 ? 60 (Y 1544) Cumancaya A.D. 810 ? 80'(Y 1545) Nueva Esperanza Cashibocanio Pacacocha Yarinacocha Hupa iya Late Shakimu Early Shakimu 650 B.C. ? 100 (Y 15 43) Late Tutishcainyo Early Tutishcainyo (Source: Lathrap 1968) There is likely debate as to why habitation has persisted in these specific locations. One potential hypothesis is based upon the river dynamics of the Central Ucayali. Because of the h eavy sediment load carried by the Ucayali there is significant deposition of sediments, and subsequently drastic meandering of the river. Though it has not yet been investigated, it is possible that these ADE site s consist of a more stable parent material and were less likely to erode. As such, early Amerindians may have sought out these locatio ns for settlement sites through out different waves of migration. Ad ditionally, it can be hypothesi zed that these sites were sought out throughout different waves of migration for their greater fertility. Numerous studies have noted that modern inhabitants are aware of the greater fertility of ADE ( Fraser et al. 2009; Hiraoka et al. 2003; Smith 1980 ). Hence, it is possible that early inhabitants were aware of these properties as well. Yet due to the lack of empirical evidence and small sample
32 size of this study, it is entirely possible that this recurrent habitation in the three areas investigated happened purely through chance.
33 CHAPTER 2 CONTEMPORARY AGRICUL TURAL USE OF AMAZONIAN DARK EARTH IN THE UCAYALI REGION OF PERU Land Use Methods on ADE This chapter describes the land use practices on ADE sites encountered in the vicinity of San Francisco de Yarinacocha, San Rafael, and Limongema in the department of Ucayal i, Peru. It describes in detail four sites in the vicinity of San Francisco de Yarinacocha which differed drastically in their land uses. Additionally, it discusses in greater depth the typical management practices encountered in home gardens on ADE and no n ADE in this region. A total of 17 ADE sites were encountered in the settlements of San Francisco de Yarinacocha, Santa Clara, Sapotillo, Siete de Junio, Dos de Mayo, Nueva Esperanza, San Rafael and Limon g ema. Table 2 1 show s the locations and uses of ea ch ADE site encountered in this study. Table 2 1 Locations and land uses of all sites encountered Location Land Use San Francisco Home garden Santa Clara Fallow pasture Sapotillo Annual agricultural field Siete de Junio Home garden and sheb n plantati on Siete de Junio Home garden San Rafael Home garden San Rafael Home garden San Rafael Home garden Nueva Esperanza Home garden Nueva Esperanza Home garden San Francisco Home garden San Francisco Home garden San Francisco Home garden San Francisco Ethnobotanical garden Limon g ema Home garden Limon g ema Home garden Limon g ema Home garden
34 Of the 17 sites, 1 3 were used for home gardens alone (76 %), one was used for a n annual agricultural field ( chacra ) (6%), one was a regenerating forest on fallow p asture land (6%) one was a combination of home garden and sheb n ( Attalea butyracea ) plantation (6%) and the other was an ethnobotanical garden designed to preserve traditional Shipibo medicinal plants (6%). The ADE sites used for home gardens will be dis cussed in great er detail in the next section This section will address the management practices of the chacra, fallow pasture sheb n plantation and ethnobotanical garden. The ADE chacra encountered in Sapotillo approximately 40 minutes from San Francis co, was the only site encountered which was used specifically for annual agriculture alone. The current land manager had recently acquired this land and this was only the first season of planting. He had heard stories of the pre vious land owner harvesting manioc and encountering entire ancient ceramic pots. Ceramic fragments were evident throughout the surface of the site and the color was notably darker than surrounding soils. Crops cultivated in this plot were pla ntain, maize, manioc and cow pea (chiclayo) Though the primary purp ose was to produce crops for in home use, he stated that a small portion of the crops were destined for the market. Regarding the use of pesticides and fertilizers, none were currently being used and the reasoning for this was simp ly that this was the custom of the area Weed management involved a combination of pre plant burning and subsequent machete work to keep the weeds under control. The fallow pasture was encountered in Santa Clara approximately 20 minutes outside of San Fran cisco de Yarinacocha. This site was along the main road and
35 ceramic fragments could be seen in the road cut as well as littering the road way The soil color was notably darker and extended beyond 1 meter as evidenced by the road cut. This plot had been fal low for approximately 10 years and the reason cited for this was that the previous owner had moved into Pucallpa and could no longer manage t he land. L oss of fertility was not cited as a reason for abandonment of agricultural activities. Though the plot wa s under natural forest regeneration there was still usage of this area to gather firewood and other forest products. In Sie te de Junio one site was encountered that was used for both a home garden and a portion of the adjacent sheb n plantation. The hom e garden was located in the core of the site where ceramic fragments were clearly visible in both the yard and roadway. Additionally the soil contin ued to be darker throughout one third of the sheb n plantation and the owner cited that he had encountered ceramics while planting in this area. The land owner was not aware of any difference in fertility between the ADE area and non ADE area of the plantation. Management practices of the home garden did not differ greatly from other sites encountered Sheb n i s a palm grown for thatch and an inherently easy crop to manage once mature. The dense canopy shades out some of the weeds and the palms do not require intensive management such as fertilization and pesticide use Any weeds present were managed with a mach ete and no fertilizers or pesticides were used. The owner cited that the majority of the work in his plot came during harvest of the fronds and he often had assistance from friends or family for this work. The ethnobotanical garden encountered in San Fran cisco de Yarinacocha which was intended to preserve traditional medicinal plants of the Shipibos, was perhaps one
36 of the most interesting uses of ADE and had extremely high diversity. Though no ceramic fragments were encountered in the site visit, the ow ner cited that he had previously encountered ceramics while planting. The soil color throughout most of this area was darker though because of the large size of this property some of the peripheral areas did not show a darker color. S ome small plots conta ined annu al plants such as maize and manioc similar to an annual chacra field, while the area immediately adjacent to the house more strongly resembled a typical home garden with fruit trees and other plants for use in the home. The majority of the proper ty was planted with a variety of traditional Shipibo medicinal plants and the owner cited that he had over 125 different varieties. He occasionally sold some of the medicinal plants within the community but noted a decline in demand because traditional me dicine has lost popularity and a health care center has opened in San Francisco. Despite the lack of demand for traditional medicinal plants, he was still proud to be preserving traditional Shipibo knowledge. Management Practices of Home Gardens on ADE a nd Non ADE Soil The primary land use of ADE in the Ucayali region was found to be home gardens (76 %) Hiraoka et al. ( 2003 ) state that the most common use of ADE in the middle Amazon is for kitchen gardens and agroforests. Because this type of land use was so prevalent, data were also collected for non ADE home gardens to provide a comparison of soil fertility, agrobiodiversity and management practices Soil fertility appeared to vary widely in both the ADE and non ADE samples and this will be further analy zed in Chapter 4 Additionally, agrobiodiversity will be addressed in Chapter 3 This section will provide a comparison of management practices in ADE and non ADE home gardens.
37 Home gardens are cultivated primarily for in home use and are generally not co nsidered an economic activity. Market orientation did not appear to vary with distance to markets. This is in contrast to studies by Kawa (2008) Kawa et al. (2011) and Fraser (2010) that showed a greater market orientation with shorter distances to market s. As could be expected there were very few gardens encountered where products were being sold. Of the ADE gardens surveyed only two (14%) cited growing crops for the market, one producing camu c amu ( Myr ciaria dubia ) and the other producing s heb n for roof thatch. None of the non ADE home gardens were cited as cultivating plants for sale. However, though most of the participants said that they did not sell the products from their home gardens some of the ADE and non ADE home gardens were found to contain p lants such as h uingo ( Crescentia cujete ) and h uayruro ( Oromosia amazonica ) that are used to make craft s which are then sold to tourists. The prevalence of these artisan products in home gardens was higher in native Shipibo home gardens than in ribeirinho g arden s Ribeirinhos are rural settlers of mixed ancestry who do not have direct ties to one particular indigenous culture. The majority of participants surveyed responded that they used no fertilizers or pesticides in their home gardens. This is in contras t to a study by Kawa (2008) on the Madeira River which found that 50% of ADE farmers used chemical fertilizers. This is likely due to the greater market orientation and the use of ADE to produce nutrient demanding annual crops such as watermelon. In one of the ADE gardens in Siete de Junio the owner stated that he used worm castings to fertilize his fruit trees but had never used synthetic fertilizers. Thou gh no other respondents used fertilizers, it was common practice to use food waste to help maintain th e fertility of the garden. Some
38 participants in this study did not identify this as active fertility management rather as waste disposal Home gardens can be described as systems where the inputs balance the outputs (Kumar and Nair 2004) The food waste added to the home gardens likely contributes significantly to the fertility of both ADE and non ADE gardens. Increased weed growth is often cited as one of the drawbacks to ADE cultivation. Increased weed populations, compete with crops and can harbor pest s and diseases (Pimentel 1991). In addition weed control requires a significant amount of labor which may not be available in some households. German (unpublished data) found that ADE farmers spend 30% of their time on weed management as opposed to non A DE farmers who dedicate only 17% of their time to weed management (Major et al. 2003). Weed management did not appear to differ drastically between the ADE and non ADE gardens in this study In all gardens the participants said they used a machete to con trol weeds and it is likely that the structure of the home gardens with greater shade helps to control some of the increased weed pressure in ADE home gardens Labor was not found to be a limiting factor in weed management of home gardens because in most cases the task is shared among all members of the family old enough to wield a machete.
39 CHAPTER 3 SPECIES DIVERSITY OF ADE HOME GARDENS Agrobiodiversity Home gardens are located in the immediate area surrounding the residence and defined by Nair et al. Home gardens can be found in almost all tropical and subtropical areas where subsistence land use is a dominant f eature (Fernandes and Nair 1986 ). The high species diversity of these systems has been noted by Fernandes and Nair (1986) as an agricultural method by which to avoid the land degradation seen with monoculture agricultural practices. This is in part due to of home gardens (Kumar and Nair 2004). In addition, home gardens have long been regarded as important reservoirs of agrobiodiversity in the tropics (Smith et al. 1998) They provide a variety of p roducts for in home use and occasionally the surplus is sold. Home gardens often serve as a testing ground for new crops prior to introduction into the chacra In a study on the agrobiodiversity of ADE, Fraser et al. ( 2011) showed that agrobiodiversity in a variety of land use systems is higher on ADE. The current study addresses the agrobiodiversity of home gardens on ADE, and hypothesizes that agrobiodiversity is greater in ADE home gardens than those found on the native terra firme soils.
40 A B Figure 3 1. Examples of home garden structure and composition in the study area. P hotos courte sy of author. (A) Home gar den in Siete de Junio with mango and plantain (B) Home g arden in Nueva Esperanza w ith aguaje and papaya (C) Home g arden in Lim ongema with manioc (D) Home g arden in San R afael with plantain and squash
41 C D Figure 3 1. Continued Photos courtesy of author.
42 An average of 16.1 (s= 2.44) species was found in ADE home gardens in this study compared to the 15.0 (s= 6.15) species found in non ADE home gardens When diversity was examined in relation to the overall size of each home garden, the number of species per square me ter was found to be 0.0342 (s= 0.0087) for A DE home gardens and 0.0309 (s= 0.0151) for non ADE home gardens. These values do not reflect the overall density of plantings, as often th ere were multiple plants of each individual species. The following two sections will discuss the relative frequencies of different kinds of crops found in ADE and non ADE home gardens. Table 3 1 shows the species encountered in this study. A Comparison of Native and N on Native Crops A large portion of exotic crops appear to be better adapted to ADE soil ( Fraser et al. 2011 ). Some exotic species likely came from regions with soils that have qualities more similar to ADE than the native upland soils such a s higher nutrient content and less acidic pH. A variety of studies have shown that agricultural and agroforestry systems on ADE exhibit a higher proportion of exotic species than those on non ADE soil (German 2001; Clement et al. 2003; Major et al. 200 5; Fraser 2009; Fraser et al. 2011 ). This study hypothesizes that the prevalence of exotic species will be greater in ADE home gardens because of the increased soil fertility. The table in Appendix A shows all species encountered for each ADE and non ADE home garden surveyed. For some species only the Shipibo name was known and the corresponding scientific name was not found. Despite the hypothesis that non native crops are more prevalent on ADE soil, it was found in this study that the over all differen ce was negligible. ADE gardens
43 Table 3 1 Number of occurrences and relative frequencies of all species encountered in both ADE and non ADE home gardens Common Name Scientific Name Occ ADE Rfreq (%) Occ non ADE Rfreq (%) Achiote Bixa orellana 0 0.00 2 14.29 Aguaje Mauritia flexuosa 3 21.43 3 21.43 Ahusciro 1 7.14 0 0.00 Aji dulce Capsicum spp. 3 21.43 0 0.00 Aji picante Capsicum spp. 0 0.00 2 14.29 Algodon Gossypium barbadense 3 21.43 4 28.57 Almendra Terminalia catappa 1 7.14 1 7.14 Amasisa Erythrina fusca 0 0.00 1 7.14 Anona Rollinia mucosa 0 0.00 2 14.29 Ayahuasca Banisteriopsis caapi 3 21.43 2 14.29 Ayahuma Couroupita guianensis 1 7.14 0 0.00 Beco 1 7.14 0 0.00 Bolaina Guazuma ulmifolia 1 7.14 3 21.43 Cacao Theobroma cacao 4 28. 57 2 14.29 Caf Coffea arabica 2 14.29 0 0.00 Caimito Pouteria caimito 7 50.00 11 78.57 Camote Ipomoea batatas 0 0.00 3 21.43 Camu camu Myrciaria dubia 2 14.29 1 7.14 Caa Saccharum officinarum 4 28.57 4 28.57 Cangarana 1 7.14 0 0.00 Caoba Swiete nia macrophylla 2 14.29 2 14.29 Capirona Calycophyllum spruceanum 1 7.14 0 0.00 Carambola Averrhoa carambola 1 7.14 3 21.43 Cashu Anacardium occidentale 2 14.29 4 28.57 Cedro Cedrela odorata 2 14.29 1 7.14 Chacruna Psychotria viridis 3 21.43 2 14.29 Chanca piedra 1 7.14 0 0.00 Chiclayo Vigna unguiculata 0 0.00 1 7.14 Chirimoya Annona cherimola 2 14.29 0 0.00 Chirisanango Brunfelsia grandiflora 1 7.14 0 0.00 Choloque Sapindus saponaria 0 0.00 2 14.29 Ciruela Bunchosia armeniaca 1 7.14 0 0.00 C oca Erythroxylum coca 1 7.14 0 0.00 Coco Cocos nucifera 12 85.71 10 71.43 Cocona Solanum sessiliflorum 1 7.14 1 7.14 Cormin Vitex pseudolea 0 0.00 1 7.14 Culantro Eryngium foetidum 1 7.14 0 0.00
44 Table 3 1. Continued Common Name Scientific Name Oc c ADE Rfreq (%) Occ non ADE Rfreq (%) Granadilla Passiflora ligularis 1 7.14 1 7.14 Guaba Inga edulis 9 64.29 10 71.43 Guanbana Annona muricata 2 14.29 2 14.29 Guayaba Psidium guajava 8 57.14 8 57.14 Guisador Curcuma longa 0 0.00 1 7.14 Hierbaluis a Cymbopogon citratus 3 21.43 2 14.29 Huacapurana Campsiandra angustifolia 1 7.14 0 0.00 Huayruro Oromosia amazonica 3 21.43 4 28.57 Huingo Crescentia cujete 3 21.43 3 21.43 Huito Genipa americana 5 35.71 2 14.29 Ishpingo Amburana cearensis 3 21.43 1 7.14 Kione 0 0.00 1 7.14 Limn Citrus aurantifolia 10 71.43 8 57.14 Lupuna Ceiba pentandra 1 7.14 0 0.00 Macambo Theobroma bicolor 0 0.00 2 14.29 Malva Malva sp. 1 7.14 2 14.29 Mamey Syzygium jambos 3 21.43 1 7.14 Mandarina Citrus reticulata 4 28 .57 3 21.43 Mango Mangifera indica 10 71.43 8 57.14 Maracuy Passiflora edulis 0 0.00 1 7.14 Marosa Pfaffia iresinoides 1 7.14 0 0.00 Melon Cucumus sp. 0 0.00 1 7.14 Mucuna Petiveria alliacea 3 21.43 1 7.14 Muesce 1 7.14 0 0.00 Naranja Citrus sin ensis 5 35.71 3 21.43 Nen 1 7.14 0 0.00 Nene 1 7.14 0 0.00 Nona Annona reticulata 1 7.14 0 0.00 Pacae Inga velutina 1 7.14 0 0.00 Paico Chenopodium ambrosioides 1 7.14 1 7.14 Palillo Campomanesia lineatifolia 2 14.29 0 0.00 Palma aceitera Elae is guineensis 1 7.14 2 14.29 Palta Persea americana 0 0.00 1 7.14 Pampa oregano 1 7.14 0 0.00 Pandisho 1 7.14 0 0.00 Papaya Carica papaya 2 14.29 5 35.71 Parallijo 1 7.14 0 0.00 Parinari Couepia spp. 1 7.14 0 0.00
45 Table 3 1. Continued Co mmon Name Scientific Name Occ ADE Rfreq (%) Occ non ADE Rfreq (%) Pashaca Microlobium acaciifolium 1 7.14 0 0.00 Pataquina blanco Xanthasoma violaceum 1 7.14 0 0.00 Pepino Cucumis sativus 1 7.14 0 0.00 Pihuayo Bactris gasipaes 2 14.29 2 14.29 Pia Ananas comosus 2 14.29 6 42.86 Pion blanco Jatropha curcas 2 14.29 3 21.43 Pinon negro Jatropha gossypifolia 8 57.14 6 42.86 Piri piri Cyperus articulatus 0 0.00 1 7.14 Plantanos Musa sp. 13 92.86 9 64.29 Retama Spartium junceum 0 0.00 1 7.14 Saban 1 7.14 0 0.00 Sanango Tabernaemontana sp. 0 0.00 1 7.14 Sandia Citrullus lanatus 2 14.29 5 35.71 Sangre de grado 2 14.29 2 14.29 Santiago Croton lechleri 1 7.14 0 0.00 Sapote Quararibea cordata 1 7.14 3 21.43 Setico C ecropia sp. 1 7.14 0 0.00 Shacapa Pariana radiciflora 0 0.00 2 14.29 Shapaja Attalea phalerata 0 0.00 1 7.14 Sharomashu 1 7.14 0 0.00 Shebn Attalea butyracea 9 64.29 9 64.29 Shimbillo Inga sp. 1 7.14 0 0.00 Tanonin 2 14.29 0 0.00 Taperiba Spondias dulcis 1 7.14 1 7.14 Tapicho 1 7.14 0 0.00 Tauari Couratari guianensis 1 7.14 3 21.43 Tobaco Nicotiana tabacum 1 7.14 0 0.00 To Brugmansia versicolor 1 7.14 0 0.00 Toronja Citrus paradisi 2 14.29 3 21.43 Uvilla Pourouma cecropiai folia 1 7.14 0 0.00 Ua de gato Unc aria tomentosa 0 0.00 1 7.14 Yama plata 1 7.14 0 0.00 Yarina Phytelephas macrocarpa 1 7.14 1 7.14 Yawancha 1 7.14 0 0.00 Yuca Manihot esculenta 4 28.57 5 35.71 Zapallo Cucurbita maxima 1 7.14 1 7.14
46 surveyed showed only a slightly higher perc entage of non native crops (33.9 %) than non ADE home gardens (30.0%). However, c ertain non native species such as coconut ( Cocos nucifera ) and plantain ( Musa sp. ) did show higher relative frequencies in the ADE home gardens. Coconut was found in 92.7% of t he ADE home gardens and 71.4% of the non ADE home gardens. Plantain was found in almost all of the ADE home gardens surveyed and only 64.3% of the non ADE home gardens. Additionally some species such as coffee ( Coffea arabica ), cherimoya ( Annona cherimola ) and tobacco ( Nicotiana tabacum ) were found only in ADE home gardens and were entirely absent from non ADE home gardens. Figure 3 2 shows the relative frequencies of non native species that were more common in ADE home gardens Figure 3 2 Relative frequ ency of non native species that were more prevalent in ADE home gardens However, some exotic species had higher relative frequ encies in non ADE home gardens, such as cotton ( Gossypium barbadense ), carambola ( Averrhoa carambola ), chiclayo ( Vigna unguicula ta ), guisador ( Curcuma longa ), melon ( Cucumus sp. ), oil palm
47 ( Elaeis guineensis ), avocado ( Persea a mericana ), watermelon ( Citrullus lanatus ) and toronja ( Citrus paradisi ). Though it may be easier to grow certain exotic species on ADE soil, species choices may not be dependent on soil type alone Other factors that influence crop choices may be personal prefe rences, species availability, market demand and cultural aspects. Prevalence of Typical Floodplain Crops in ADE Home Gardens The floodplain is one of the most productive agricultural areas in the Amazon Basin. Unlike the uplands or terra firme, the floodplain soils are replenished by nutrients from rich river sediments (Denevan 1982) The frequency of replenishment depends upon the distance from the m ain river channel and flood intensisty and can vary from year to year Four distinct zones are recognized in the floodplains These include the sandflats, mudflats, low levees and and high levees (Schmidt 2003). Given the varying flood frequency of the d ifferent zones, crop choices for each zone also vary. According to Schmidt (2003) in a study on the Solom e s, s andflats and mudflats are typically used for producing short cycled crops such as beans, maize squash, gherkin and watermelon and occasionally fast maturing varieties of manioc On low levees beans, maize squash, gherkin, watermelon and manioc were also planted but these areas also contained longer cycled crops such as banana, sugarcane guava and cacao (Schmidt 2003) This repetition of planti ng the same species on sandflats and mudflats as well as on low levees can be an insurance measure against fast rising flood waters. Typical crops of the high levees included manioc corn and banana along with other perennial species and species with lowe r flood tolerance such as a ai, cacao, lime and pep p ers (Schmidt 2003). During this study it was found that the floodplains adjacent to the community of San Rafael had previously b een a plantain
48 producing region. H owever, except ionally high floods had wi ped out many of the plantain fields on the high levee in the previous year and many farmers interview ed reported that the y no longer sold plantains on the market In this study, crops typical ly cultivated on the floodplains were encountered in both ADE an d non ADE home gardens. Though some of these species are also cultivated in the uplands, they often perform better in the rich floodplain soils. In this study upland crops are defined as those that are rarely cultivated on the floodplains and floodplain c rops as those which are preferentially planted in the floodplains The prevalence of floodplain crops was higher in ADE home gardens for many species. Some floodplain crops were found to have equal prevalence in ADE and non ADE home gardens. However, 46.7% of the floodplain crops encountered in this study occurred more frequently in ADE home gardens while only 20% of them were more common in non ADE home gardens ( Figure 3 3 ) Figure 3 3 Relative frequencies of typical floodplain crops that were more c ommon in ADE home gardens.
49 These results are similar to what was found in the middle Amazon by Hiraoka et al. (2003). They found that in upland agroforestry systems, a greater number of typical floodplain species were cultivated in ADE agroforests than in non ADE agroforests. However, the main difference between the findings of Hiraoka et al. (2003) and this study was that a large number of palms were documented in the Middle Amazon and few were found in this study of the Central Ucayali (with the exception of coconut aguaje and sheb n) It may be simply that palms are less common in home gardens tha n mature agroforests or that palms in general could have less importance in the regions studied which were predominantly native Shipibo communities. Further r esearch is required to determine the reasons for the paucity of pa lms in home gardens in the Central Ucayali.
50 CHAPTER 4 A SOIL ANALYSIS OF ADE AND NON ADE SITES IN THE CENTRAL UCAYALI An Overview of Dominant Soil Types in the Central Ucayali Region and Their Characteristics The three most prominent soil ty pes in the Central Ucayali are oxisol s, u ltisols and i nceptisols (USDA NRCS 1999 ) Because this study focuses on upland soils and i nceptisols are predominantly found in the floodplains they will not be addressed. In contrast to many previous studies, the soil samples collected in this study were almost entirely on u ltisols with only two oxisol samples from San Rafael. Both soil orders are commonly formed under moist tropical conditions such as in the Amazon and are highly weathered (Brady and Wiel 2008) Ultisols are characterized as highly leached with an argillic or kandic horizon that forms when clays are translocated and accumulate in lower levels of the profile (Brady and Wiel 2008) They also have extensive leaching of base forming cations from the soil as well as high acidity and low plant nutrients in both in the epipedon and the subsoil (Brady and Wiel 2008) These soils are often red to yellow in color indicating accumulation of iron oxi des (Brady and Wiel 2008) With sufficient additions of fertilizers and lime these soils can be made agriculturally productive, however, most small scale farmers in the Amazon lack these resources. In general agricultural land use of these soils is limite d to shifting cultivation (USDA NRCS 1999 ). Though u ltisols are characterized as highly weathered, they are still less weathered than the o xisols that are typical of most of the Brazilian Amazon. While the cla y content is generally high in o xisols it is kaolinite and is of low activity and typically non sticky (Brady and Wiel 2008) Due to the low activity of these clays cations such as calcium, magnesium and potassium are leached out quickly (Brady and Wiel 2008)
51 In tropical soils phosphorus often li mits net primary productivity (NPP) (Cuevas 2001). They generally have a low cation exchange capacity and few weatherable minerals (USDA NRCS 1999 ). In addition to being characterized as acidic, these soils also have a high content of iron and aluminum o xides which can cause tight binding with the small amount of available phosphorus (Brady and Wiel 2008) Often when cleared these soils quickly lose fertility and subsequent plantings suffer from phosphorus deficiency. Slash and burn agriculture release s a pulse of nutrients, yet on o xisols in a year or two this is exhausted and fertilizer application or fallowing is needed (USDA NRCS 1999 ). Soil Textural Analysis Perhaps one of the most important features of a soil in determining its behavior is the tex ture. Soil texture is defined as the relative proportions of various soil particle sizes in the mineral portion of a soil (Brady and Wiel 2008) It can affect such things as nutrient retention water movement and soil structure. Coarse particles such as s and have a lower specific surface area than fine particles such as clay, and are less reactive (Brady and Wiel 2008) Though clays in general are more reactive different types of clays can vary in their reactivity and stickiness as mentioned regarding th e kaolinites clays found in o xisols in the previous section. In this study texture was determined by hydrometer and there was a difference in the texture of ADE and non ADE soils (Table 4 1 ). The majority of the ADE soils were classified as sandy loams (57.1%) while the majority of non ADE sites were classified as loams (61.5%). Previous studies have noted that ADE soils generally have a coarser texture than surrounding soils (Costa and Kern 1999; Lehmann et al. 2003). Additionally the non ADE sites ha d a higher average percentage of clay (19% as opposed to 12% in ADE soils). In most cases loam soils have a higher clay content
52 giving them a higher specific surface area than a sandy loam. This can increase the reactivity and nutrient retention capacity which may account for higher than expected nutrient contents in the non ADE soil samples. However, because the dominant clay type in tropical soils is kaolinite which is less reactive, the clay content may play less of a role in nutrient retention than th e organic matter in the soil. Nutrient content s of the soil samples will be discussed in further in subsequent sections of this chapter. Average sand content was 59% for ADE samples and 44% for non ADE samples. Silt content averaged 29% for ADE samples and 37% for non ADE samples. Table 4 1 Textural classes of ADE soil samples collected and relative percentages of sand, silt and clay. ADE Sand (%) Silt (%) Clay (%) Textural Class SF 01 47 31 22 Loam SJ 05 57 35 8 Sandy loam SJ 06 69 27 4 Sandy loam SR 09 49 41 10 Loam SR 10 35 49 16 Loam SR 12 57 29 14 Sandy loam NE 13 77 17 6 Sandy loam NE 14 65 29 6 Sandy loam SF 15 55 29 16 Sandy loam SF 17 55 25 20 Sandy clay loam SF 19 63 25 12 Loam LJ 26 71 21 8 Sandy loam LJ 26 71 21 8 Sandy loam LJ 27 51 33 16 Loam Table 4 2. Textural classes of Non ADE soil samples collected and relative percentages of sand, silt and clay. non ADE Sand (%) Silt (%) Clay (%) Textural Class DM 20 55 25 20 Sandy clay loam NE 21 4 5 45 10 Loam DM 22 43 41 16 Loam NE 23 43 39 18 Loam DM 24 37 35 28 Clay loam LJ 28 37 41 22 Loam LJ 28 37 41 22 Loam SF 29 47 35 18 Loam SF 30 37 43 20 Loam SF 31 53 35 12 Sandy loam SF 32 57 25 18 Sandy loam SF 33 47 39 14 L oam SF 34 35 35 30 Clay loam
53 Soil Org anic Matter Content of ADE and N on ADE Soil Samples As mentioned in the previous section, organic matter content plays an important role in the nutrient retention of highly weathered soil s such as oxisols and u ltis ols. Soil organic matter (SOM) influences cation exchange capacity, water holding capacity and the formation and stabilization of soil aggregates (Brady and Wiel 2008). One of the key differences between ADE and non ADE soils is the nature of the organic material present. ADE has a high charcoal content lending to its darker color. Glaser et al. (2001) found that ADE soils had as much as 70 times the black carbon content as surrounding soils. The high charcoal content and the recalcitrance of this form of organic matter are thought to increase the cation exchange capacity ( Glaser et al. 2001 ). Charcoal has a greater quantity of exchange sites than typical soil organic matter because of oxidation of aromatic carbon and the formation of carboxylic groups. (L ehmann et al. 2003). Organic matter contents were determined using the Walkly Black method. Though the average values for percent organic matter are still low for both soil types analyzed in this study, the results did show a statistically significant in crease in SOM in the ADE samples. SOM for ADE samples averaged 1.82% (s=0.54) and 1.21% (s=0.48) for non ADE samples (Table 4 3 ) The t test showed slight statistical significance (P value 0.004993) at the 95% confidence interval (see Appendix C for statis tical data). While both SOM contents are still extremely low for agricultural soils the higher SOM in the ADE samples may provide water retention and nutrient retention. Cation exchange capacity will be discussed in the following section.
54 Table 4 3 Perc ent soil organic matter for ADE and Non ADE soil samples ADE (sample #) % SOM Non ADE (sample #) % SOM SF 01 2.32 DM 20 0.67 SJ 05 2.05 NE 21 0.41 SJ 06 1.02 DM 22 1.02 SR 09 2.32 NE 23 0.75 SR 10 2.80 DM 24 1.23 SR 12 2.53 LJ 28 1.71 NE 13 1.19 LJ 28 1.71 NE 14 2.12 SF 29 1.30 SF 15 1.50 SF 30 1.84 SF 17 1.78 SF 31 0.75 SF 19 1.43 SF 32 1.09 LJ 26 1.50 SF 33 1.43 LJ 26 1.50 SF 34 1.84 LJ 27 1.37 DM 20 0.67 A Comparison of Cation Exchange Capacity (CEC) in ADE and N on ADE Soil Samples Brady and Wiel (2008) describe the cation exchange capacity as the sum of all exchangeable cations that a soil can adsorb. It is dependent both on the type and quantity of mineral colloids pr esent as well as the organic matter content of the soil. Due to the lo w activity of clays present in oxisols and u ltisols of the Amazon, the majority of the cation exchange capacity is determined by the quality and quantity of organic matter present in the soil. Both kaolinite clays and organic matter have pH dependent charge, which means that as soils become more acidic there are fewer available exchange sites and greater leaching of cations (Brady and Wiel 2008 ; Juo and Franzluebbers 2003 ). S tudies of A DE soils have documented a higher cation exchange capacity in soils with a higher charcoal content (Liang et al. 2006 ). CEC was determined in the lab using a saturation of ammonium acetate. In contrast to other studies, this study found that the cation e xchange capacity varied widely and on average was nearly equal between the ADE and non ADE samples. The
55 average CEC of ADE samples was 7.97 cmol/Kg (s=2.82) an d 8.06 cmol/Kg (s=2.40) for non ADE samples (Table 4 4 ) This may be due to the very small differ ence between the organic matter contents in the ADE and non ADE samples. Table 4 4 Cation exchange capacity for ADE and Non ADE soil samples ADE (sample #) CEC (cmol/Kg) Non ADE (sample #) CEC (cmol/Kg) SF 01 12.32 DM 20 7.68 SJ 05 8.32 NE 2 1 4.80 SJ 06 3.68 DM 22 6.40 SR 09 12.32 NE 23 5.76 SR 10 10.08 DM 24 10.24 SR 12 8.80 LJ 28 9.28 NE 13 5.12 LJ 28 9.28 NE 14 7.36 SF 29 8.80 SF 15 9.92 SF 30 9.60 SF 17 10.40 SF 31 4.32 SF 19 7.52 SF 32 9.12 LJ 26 4.80 SF 33 6.72 LJ 26 4.80 SF 34 12.80 LJ 27 6.08 DM 20 7.68 A Comparison of pH in ADE and N on ADE Soil Samples pH is defined as the concentration of hydrogen ions in a soil and is considered a master variable because it af fects chemical properties such as cation exchange capacity the solubility of aluminum physical properties such as soil aggregation and the composition of the microbiological community in a soil (Brady and Wiel 2008). Typical Amazonian soils generally ha ve a very low pH, which can negatively affect agricultural productivity. The average pH of Brazilian Amazonian soils is approximately 4.17 4.94 (Nigreiros and Nepstad 1994) which is quite low. Because aluminum is more soluble at a lower pH, crops often su ffer from aluminum toxicity (Nigreiros and Nepstad 1994).
56 In this study pH was measured using a potentiometer and the average pH of ADE soils was found to be 5.40 (s= 0.67) which is higher than the non ADE soils sampled as well as higher than the aver ages found by Nigreiros and Nepstad (1994). The average pH for non ADE soils in this study was found to be 4.68 (s= 0.33) which does fall within the average range found by Nigreiros and Nepstad (1994). This difference between the pH of ADE and non ADE soil s was found to be statistically significant at the 95% confidence interval (P value= 0.00205 ). The higher pH of the ADE samples is closer to the pH of the i nceptisols of the floodplain and may partially explain why more floodplain species were found in ADE home gardens than in non ADE home gardens. Nitrogen, Phosphor us and Potassium Levels in ADE and N on ADE Soil Samples ADE soil is thought to have a higher charcoal content than similar unmodified upland soils in the Amazon Basin. Though charcoal addition t o soil has been seen to increase agric ultural productivity in some studies (Chan and Xu 2009; Blackwell et al. 2009), it contains only small quantities of essential nutrients Though some nutrients remain i n the charcoal there is generally a net loss of nutrients from the organ ic matter converted into charcoal through pyrolysis (Chan and Xu 2009 ). Because of this loss, charcoal has a higher C:N ratio than uncharred SOM, which would be expected to cause nitrogen immobilization by microbes. However, the m ajority of the carbon is largely recalcitrant and unavailable to microbes, and nitrogen immobilization observed is negligible (Chan and Xu 2009). The analysis in this study measured percent nitrogen using the micro Kjeldahl method. This measurement includ es all forms of nitrogen in the soil. Not all forms of nitrogen will be available to plants, and as such these measurements cannot be
57 assumed to provide information on plant available nitrogen. However, the values for percent nitrogen can provide a compari son of overall nitrogen content between the two soil types investigated in this study. The average percent nitrogen found in the ADE samples was 0.10% (s=0.03), in comparison to the non ADE samples which had an average of 0.08% (s=0.02). Despite the higher average value for the ADE samples, a T test showed that this difference is not statistically significant due to the variation in the sample values and small sample size. Upland forests growing on oxisols and u ltisols in the Amazon are typically limited b y phosphorus (Cuevas 2001), and as such agricultural systems including home gardens are often limited by this nutrient as well (Oberson et al. no date ) The loss of nutrients such as phosphorus is accelerated in agricultural soils and is often exhausted after two years (Cuevas 2001). Tiessen et al. (1994) found that much of the phosphorus availability in tropical soils is controlled by organic matter dynamics. The high content of iron and aluminum oxides in tropical soils can act to occlude mineral sourc es of phosphorus making the phosphorus in organic matter more important for plant growth. Phosphorus values were obtained using the modified Olsen method. In this study average phosphorus values were found to be much higher for the ADE samples than non AD E samples. The average value for ADE samples (20.7ppm, s=14) was nearly five times that of the non ADE samples (4.5ppm, s=1.6). Despite the relatively small sample size, a T test showed that this difference is highly significant (P value 0.0008609). Greate r total phosphorus may not indicate high er available phosphorus despite the fact that the textures and composition of the two soil types were similar. In
58 addition to the mineral composition, phosphorus availability is also affected by the microbial communi ty that controls the turnover of organic matter ( Oberson et al no date ). Howe ver, no data were gathered on the microbial communities of these two soil types. Because phosphorus is often a limiting nutrient, this difference could impact the productivity o f home gardens on ADE soil if the microbial communities present were similar Unlike phosphorus, potassium occurs in the soil solution in cation form (Brady and Wiel 2008), making its availability highly dependent upon cation exchange capacity. In plants potassium helps improve resistance to stress such as drought, pests and diseases (Brady and Wiel 2008). Like both nitrogen and phosphorus, a relatively small portion of potassium is available for plant uptake (Brady and Wiel 2008). This elemen t is ofte n held strongly within the primary mineral s of a soil or fixed in forms that are only moderately available to plants. In soils dominated by kaolinite clays potassium levels are often quite low and often more abundant in deeper subsoil layers. However, home garden systems contain a variety of deep rooted perennials which can act as a sort of potassium pump by bringing the element up from deeper subsurface layers and recycling it into the system through litter fall (Brady and Wiel 2008). Because much of the biomass in home gardens is returned to the system, a large portion of the potassium cycles through the organic matter portion of the soil. Potassium was determined using an extraction of ammonium acetate at pH 7. The overall potassium content was quite hig h for some of the ADE samples analyzed in this study with an average value of 150ppm (s=97) for ADE samples, and an average value of 84.8ppm (s=27.4) for non ADE samples. This difference is statistically
59 significant at the 95% confidence interval (P value= 0.0298). However, this does not necessarily reflect the available cation potassium as only 1 2% of total soil potassium is readily available for plant uptake (Brady and Wiel 2008) The exchangeable cation potassium in the system was not significantly di fferent between ADE and non ADE samples. Average exchangeable potassium (K + ) was measured at 0.26 meq/100g (s=0.16) for ADE samples and 0.17meq/100g (s=0.05) for non ADE samples. This may reflect the small difference in the cation excha nge capacity of thes e two soils. Exchangeable Cations in ADE and N on ADE Soil Samples Exchangeable cations can be held on the negatively charged site of organic matter and colloidal mineral particles (Brady and Weil 2008). In addition to measuring the capacity of a soil to r etain these cations (CEC), it can also be helpful to look at the relative quantities and the balance of these cations (Landon 1991). Exchangeable potassium was addressed in the previous section. This section will present the results for exchangeable calci um, magnesium and sodium. Exchangeable cation levels were determined using a replacement with ammonium acetate followed by atomic absorption. Plants generally take up calcium in amounts only second to nitrogen and potassium as it is an integral component of cell walls (Brady and Weil 2008). Calcium occurs in the soil solution as a divalent cation and can be deficient in acid tropical soils (Landon 1991). In neutral to moderately acid soils, calcium can occupy 60 90% of cation exchange sites (Brady and We il 2008). This number is likely lower for strongly acid soils, yet it is still important to note the overall prevalence of this cation in the system. In both ADE and non ADE soils in this study, calcium was found to be the most prevalent cation in the sys tem. The average value for calcium cations in ADE soil samples was 4.98 meq/100g (s=2.14) and 2.89 meq/100g (s=1.54) for non ADE soil
60 samples. Landon (1991) states that a high value for calcium in tropical soils is close to 10 meq/100g. Though the ADE valu e is less than half of the high calcium level, the difference between the two soil types in this study was statistically significant. Like calcium, m agnesium is also present in divalent cationic form, though in much lower quantities. In the past, soil sc ientist s believed that the ratio of calcium to magnesium was critical in agricultural soils (Brady and Weil 2008). However, in recent years studies have shown that plants grow well in a range of calcium magnesium ratios (Brady and Weil 2008). In tropical acid soils, magnesium deficiency typically occurs at values below 0.5 meq/100g (Landon 1991). Neither soil type in this study exhibited low enough levels for magnesium deficiency to be a significant issue. The ADE samples had an average value of 0.85 meq /100g (s=0.49) and the non ADE samples were slightly lower at 0.79 meq/100g (s=0.44). The difference in these values was not statistically significant. Sodium occurs as a monovalent cation on the exchange complex but is not essential for plant growth (Lan don 1991). Measurements of sodium in soils are more important in arid regions than heavily leached tropical soils, as toxicity rarely occurs with adequate rainfall and drainage (Brady and Weil 2008). As expected, the measurements for sodium in both soil types were quite low. ADE soil samples showed an average value of 0.15 meq/100g (s=0.9). Non ADE soil samples were similar with an average value of 0.15 meq/100g (s=0.8). Because the re is no significant difference in sodium contents it is unlikely that thi s cation has any impact on plant growth on either type of soil.
61 Micronutrients in ADE and N on ADE Soil Samples Trace elements or micronutrients are those required in smaller quantities by plants. Though they are not required in large amounts, nutrient ba lance is essential for optimal plant growth, as some enzymes require more than one element for activity and some elements are required for the optimal usage of other elements (Brady and Weil 2008). In strongly acid soils (pH less than 5), such as those in the Amazon, micronutrient deficiencies may be a problem particularly under intensive cropping systems (Juo and Franzluebbers 2003). Given the minimal management of home gardens in this study, micronutrient deficiency is likely less of a problem in these systems than in the more intensive chacra systems. In addition to the cations discussed in the previous section, the trace elements measured in this study were boron, copper, iron, manganese and zinc. B oron exists in anionic form and is a commonly deficie nt micronutrient. However, acid conditions generally increase the solubility and availability of boron. Yet, in sandy soils with high rainfall boron can be easily leached. In acid soils the total boron measured is often a good indicator of plant available boron (Landon 1991). Soils in humid and temperate regions generally have boron contents between 0.2 and 1.5ppm while arid soils contain much higher levels (Landon 1991). The ADE samples analyzed in this study had an average of 0.3ppm (s=0.2) and the non ADE samples averaged 0.2ppm (s=0.17). Statistically this is not a significant difference. Both types of soil are considered to be boron deficient having a value below 0.7ppm (Landon 1991). Copper exists in the soil solution primarily as a divalent catio n and is strongly attracted to organic matter (Landon 1991). The availability of copper is affected by pH, where it becomes less available in high pH soils (Landon 1991). Total copper in soil
62 generally falls within the range of 2 100ppm, with toxicity oc curring above 100ppm (Landon 1991). The average copper content in ADE samples was 2.1ppm (s=0.9) and 1.4ppm (s=0.57) for non ADE samples. Like boron, this result was not statistically significant. Iron is most soluble at pH levels between 4.0 and 5.5, s imilar to those found in this study (J uo and Franzluebbers 2003). It is also the fourth most abundant element in 1991). The primary form is ferric oxides which are generally insoluble and unavailable to plants (Landon 1991) The average value for ADE samples was 538.8ppm (s=256.3) and 1001.2ppm (s=532.6) for non ADE samples. A T test showed this increase in non ADE samples to be statistically significant. Manganese is avail able to plant s in the soil solution as a divalent cation and the availability depends upon pH and the redox state (Landon 1991). At low pH values (less than 5.5) toxicity can occur when manganese contents reach 2,000ppm or above (Landon 1991). Despite th e low pH values of both types of soil, neither was anywhere close to exhibiting toxicity. The total average manganese content for ADE samples was 6.9ppm (s=2.1) and 10.2ppm (s=3.15) for non ADE samples. This di f ference was statistically significant and con sistent with expectations, as the pH was significantly lower in the non ADE samples. Like manganese z inc is present in the divalent cation form in the soil solution, and as such availability can be dependent upon the cation exchange capacity (Landon 199 1). Acid soils rarely exhibit zinc deficiency or toxicity (Landon 1991) although in this study the values for the non ADE soil were found to be below optimum levels. The
63 average value for zinc in ADE soils was 11.8ppm (s=7.1) and 9ppm (s=5.0) for non AD E soils However, this difference was not statistically significant.
64 CHAPTER 5 CONCLUSIONS In the study region selected for this research, the Central Ucayali in Peru contemporary ADE use had not yet been investigated. In addition, the communities invol ved in this study were primarily native Shipibo communities, whereas the work conducted in the Brazilian Amazon primarily involved caboclo or ribeirinho communities. Significant differences were noted in the primary uses of ADE. The main question s this stu dy seeks to address are: How are farming practices and crop choices different on ADE and non ADE soils? How does plant diversity and fertility vary between ADE and non ADE soils? In regards to management practices in ADE and non ADE home gardens, there we re generally no differences between how ADE and non ADE home gardens were managed. However, plant diversity and fertility did vary between ADE and non ADE home gardens The specific research questions investigated will be examined in greater depth in this chapter How are farmers managing the fertility of ADE soil? Are these practices sustainable even when nutrient demanding market crops are being grown? Are farmers using pesticides and synthetic fertilizers or crop rotations and organic soil amendments on ADE? How do these management strategies differ from those on adjacent non ADE soils? In general, the fertility management practices for ADE and non ADE home gardens did not differ greatly. T he mangement of home gardens is more similar to mature agroforestr y systems than to the chacra system and the use of fertilizers and pesticides was almost entirely absent. Generally, management involves minimal tillage, diverse planting and leaving much of the biomass from weeds and litterfall in place. Additionally, ho me gardens serve as refuse disposal sites, further increasing the organic matter of the soil. When asked why they did not use fertilizers, most participants in this
65 st udy responded that it was simply their custom and they did not see the need for external inputs. This custom likely stems from the fact that home gardens are not economically oriented. Because most of the products were for in home use, there was no need to increase the productivity with purchased fertilizers. Is ADE soil preferred for annual cropping or perennial agroforestry systems? If agroforestry is preferred, are nitrogen fixing trees being used for fertility or are the primary tree species those with economic value? In contrast to previous ADE studies in the Brazilian Amazon, this study documented very little use of ADE for annual agriculture. Of the 17 ADE sites encountered 14 of them were used for home gardens a form of agroforestry Nitrogen fixing trees were not intentionally incorporated for fertility purposes Rather, species were selected for their usefulness within the household. The species planted in home gardens on both types of soil likely reflect personal preferences and family needs rather than direct exploitation of higher fertility in the ADE soil. The fact that most of t he ADE sites were inhabited and therefore only used for home gardens may have been intentional or circumstantial, but the determination of the reason for this is beyond the scope of this study. Anecdotal evidence in this study showed that most of the par ticipants interviewed were not acutely aware of the fertility differences between ADE and typical upland soils. This may indicate that these sites were not in fact selected for their fertility. Lathrap (1968) documented 12 different waves of migration into the San Francisco de Yarinacocha area indicating long term utilization of this particular site for habitation. It is possible there are other factors that have made this site desireable for habitation. Further research is needed to determine what factors lead to contemporary habitation on these ADE sites.
66 How drastically does the fertility of ADE home gardens differ from the fertility of non ADE home gardens? Despite the fact that CEC did not differ appreciable between the ADE and non ADE home gardens in t his study, there were significant differences in some of the other fertility factors. Most notable was the diferen ce in phosphorus content of the two soil types. Phosphorus is often a limiting nutrient in tropical ecosystems, so the four fold increase in t he phosphorus content in ADE soil may play a significant role in the fertility of ADE home gardens. Additionally, the organic matter content, pH, calcium and potassium levels were significantly higher for the ADE samples. Though elevated levels of boron, c opper and zinc were also found for ADE samples, these differences were not statistically significant. There may have been greater significance with a larger sample size. The understanding of ADE soils in the Peruvian Amazon would benefit from future studie s with a greater number of samples of both the ADE and non ADE soils. Is the plant diversity higher in ADE home gardens ? Overall plant diversity did not differ significantly between ADE and non ADE home gardens. However, there were some species that occurr ed more frequently in ADE home gardens. The lack of difference in overall home garden diversity is likely due to the fact that the species selected are incorporated for their usefulness to the household. Factors such as personal preferences, needs or prior knowledge of medicinal plants play a role in which species each household selects. How does the species composition compare between ADE and non ADE home gardens ? Though overall agrobiodiversity did not differ greatly between the two types of soil, it is important to note that ADE home gardens had a greater proportion of species commonly cultivated on the floodplain s The higher proportion of floodplain species
67 does not necessarily reflect intentional planting of these species due to awareness of greater s oil fertility. Rather, it is likely due to greater success in experimentation with floodplain species on ADE soil. One of the non ADE home gardens just outside of San Francisco de Yarinacocha had relatively high diversity of species both from the upland an d the floodplains. However, most of these plants were relatively young and it is possible that with time that the soil will not support some of the species with higher fertility requirements. This study presents data on ADE use from a region that has no t been extensively studied in this regard. Some of the deviations from the expected results such as CEC and types of land use systems, may be due to both native soil differences and cultural differences between the Peruvian and Brazilian Amazon. The most common soil type in the Braz ilian Amazon is o xisols. However, the majority of samp le sites in this study were on u ltisols. Though both soil types are highly weathered, there may be subtle differences that account for the negligible difference in CEC. Cult ural factors may be influencing the land use systems in the study region Because the communities surveyed in this study were primarily native Shipibo communities, there may have been differences in initial settlement patterns compared to the ribeirinho co mmunities involved in prior ADE use studies in the Brazilian Amazon Further research could help clarify differences in land use in relation to cultural factors. This study does not address the reasons for Shipibo habitation on ADE sites, rather it simply documents the methods of use and provides a comparison of agrobiodiversity The greater success of floodplain species in ADE home gardens indicates that these soils may be able to support a wider range of crops. Agroforestry systems tend to
68 have much high er agrobiodiversity than typical annual agriculture. As such, I propose that future biochar research and terra preta nova projects focus on incorporating these technologies into agroforestry systems to maximize the biodiversity of these systems. Though the re may also be some benefits in annual agriculture, the greatest benefits may be seen in agroforestry systems.
69 APPENDIX A SPECIES LISTS FOR AL L HOME GARDENS SURVEYED Soil Sample Number: SF 01 ADE Common Name Scientific Name Ayahuasca Banisteriopsis caapi Caimito Pouteria caimito Coco Cocos nucifera Guayaba Psidium guajava Hierbaluisa Cymbopogon citratus Huingo Crescentia cujete Limn Citrus aurantifolia Mandarina Citrus reticulata Mango Mangifera indica Naranja Citrus sinensis Pashaca Mic rolobium acaciifolium Pia Ananas comosus Pion negro Jatropha gossypifolia P latano Musa sp. Taperiba Spondias dulcis Soil Sample Number: SJ 05 ADE Common Name Scientific Name Camu camu Myrciaria dubia Chirimoya Annona cherimola Guayaba Psidium g uajava Huayruro Oromosia amazonica Limn Citrus aurantifolia Mango Mangifera indica M uesce Naranja Citrus sinensis Palillo Campomanesia lineatifolia P arallijo Platano Musa sp. Shebn Attalea butyracea
70 Soil Sample Number: SJ 06 ADE Common Name Scientific Name A husciro Aji Capsicum spp. Caa Saccharum officinarum C hirisanango Brunfelsia grandiflora Coco Cocos nucifera Guaba Inga edulis Guayaba Psidium guajava Hierbaluisa Cymbopogon citratus Limn Citrus aurantifolia M ango Mang ifera indica M ucuara Petiveria alliacea N aranja Citrus sinensis P latano Musa sp. Shebn Attalea butyracea Soil Sample Number: SR 09 ADE Common Name Scientific Name Algodon Gossypium barbadense Chanca piedra Phyllanthus niruri Coco Cocos nucifera Culantro Eryngium foetidum Guaba Inga edulis Guayaba Psidium guajava Huito Genipa americana Mango Mangifera indica Paico Chenopodium ambrosioides Pataquina blanco Xanthasoma violaceum Pion blanco Jatropha curcas Pi on negro Jatropha gossypifolia Platano Musa sp. Santiago Croton lechleri Shebn Attalea butyracea Tanonin
71 Soil Sample Number: SR 10 ADE Common Name Scientific Name Aceituna Olea europaea Algodon Gossypium barbadense Caa Saccharum officinarum Coco Cocos nucifera Cocona S olanum sessiliflorum Guaba Inga edulis Guayaba Psidium guajava Limn Citrus aurantifolia Mango Mangifera indica M ucuna Mucuna pruriens P ampa oregano Pepino Cucumis sativus Pion negro Jatropha gossypifolia Platano Musa sp. Shebn Attalea but yracea Y awancha
72 Soil Sample Number: SR 12 ADE Common Name Scientific Name Caimito Pouteria caimito Coco Cocos nucifera Granadilla Passiflora ligularis Huayruro Oromosia amazonica Huingo Crescentia cujete Huito Genipa americana Pion negro Jatropha gossypifolia Platano Musa sp. Sandia Citrullus lanatus S haromashu Shebn Attalea butyracea Tanonin T apicho Soil Sample Number: NE 14 ADE Common Name Scientific Name Aguaje Mauritia flexuosa Ayahuma Couroupita guianensis Capi rona Calycophyllum spruceanum Cedro Cedrela odorata Chirimoya Annona cherimola Guanbana Annona muricata Ishpingo Amburana cearensis Mandarina Citrus reticulata N aranja Citrus sinensis Palma aceitera Elaeis guineensis Papaya Carica papaya Parina ri Couepia spp. Sangre de grado Croton lechleri Shimbillo Inga sp. Tangarana Triplaris surinamensis
73 Soil Sample Number: NE 13 ADE Common Name Scientific Name B olaina Guazuma ulmifolia Cacao Theobroma cacao Caf Coffea arabica Caimito Pouteria caimito Caa Saccharum officinarum Coco Cocos nucifera Guaba Inga edulis Guanbana Annona muricata Guayaba Psidium guajava Limn Citrus aurantifolia Mandarina Citrus reticulata Mango Mangifera indica Mucura Petiveria alliacea Naranja Citrus sin ensis Pijuayo Bactris gasipaes Pion blanco Jatropha curcas P latano Musa sp. Sapote Quararibea cordata Tauari Couratari guianensis Toronja Citrus paradisi
74 Soil Sample Number: SF 15 ADE Common Name Scientific Name Aji dulce Capsicum spp. Camu c amu Myrciaria dubia Carambola Averrhoa carambola Cashu Anacardium occidentale Chacruna Psychotria viridis Coco Cocos nucifera Guaba Inga edulis Guayaba Psidium guajava Huito Genipa americana Limn Citrus aurantifolia Malva Malva sp. Mango Mangif era indica P andisho Pla tanos Musa sp. Pomorosa/Mamey Syzygium jambos Yarina Phytelephas macrocarpa Manioc Manihot esculenta
75 Soil Sample Number: SF 17 ADE Common Name Scientific Name Aguaje Mauritia flexuosa Aji dulce Capsicum spp. Coco Coco s nucifera Guaba Inga edulis Huito Genipa americana Limn Citrus aurantifolia Ll ama plata Lindernia crustacea Mamey Syzygium jambos Mandarina Citrus reticulata Mango Mangifera indica Nen Morinda citrifolia Nona Annona reticulata Palillo Campoman esia lineatifolia Pion negro Jatropha gossypifolia Platano Musa sp. Setico C ecropia sp. Shebn Attalea butyracea Tanonin Tobaco Nicotiana tabacum Toronja Citrus paradisi
76 Soil Sample Number: SF 19 ADE Common Name Scientific Name Algodon Gos sypium barbadense Almendra Terminalia catappa Beco Caimito Pouteria caimito C angarana Triplaris surinamensis Caoba Swietenia macrophylla Cedro Cedrela odorata Chacruna Psychotria viridis Coco Cocos nucifera Huingo Crescentia cujete Limn Citr us aurantifolia Mamey Syzygium jambos Mango Mangifera indica Platano Musa sp. Saban Shebn Attalea butyracea
77 Soil Sample Number: LJ 26 ADE Common Name Scientific Name Ayahuasca Banisteriopsis caapi Cacao Theobroma cacao Caf Coffea arabica Caimito Pouteria caimito Ciruela Bunchosia armeniaca Coca Erythroxylum coca Coco Cocos nucifera Guaba Inga edulis Huacapurana Campsiandra angustifolia Ishpingo Amburana cearensis Marosa Pfaffia iresinoides N ene Pion negro Jatropha gossypifo lia Platano Musa sp. S angre de grado Croton lechleri Shebn Attalea butyracea To Brugmansia versicolor Manioc Manihot esculenta
78 Soil Sample Number: LJ 26 ADE Common Name Scientific Name Aguaje Mauritia flexuosa Cacao Theobroma cacao Caimito P outeria caimito Coco Cocos nucifera Guaba Inga edulis Guayaba Psidium guajava Hierbaluisa Cymbopogon citratus Huayruro Oromosia amazonica Huito Genipa americana Ishpingo Amburana cearensis Limn Citrus aurantifolia Lupuna Ceiba pentandra Papaya Carica papaya Pihuayo Bactris gasipaes Pia Ananas comosus Pion negro Jatropha gossypifolia Platano Musa sp. Shebn Attalea butyracea Manioc Manihot esculenta
79 Soil Sample Number: LJ 2 7 ADE Common Name Scientific Name Ayahuasca Banisteriopsis c aapi Cacao Theobroma cacao Caimito Pouteria caimito Caa Saccharum officinarum Cashu Anacardium occidentale Chacruna Psychotria viridis Coco Cocos nucifera Guaba Inga edulis Limn Citrus aurantifolia Mango Mangifera indica Pion negro Jatropha go ssypifolia Platanos Musa sp. S andia Citrullus lanatus Manioc Manihot esculenta Zapallo Cucurbita maxima
80 Soil Sample Number: DM 20 Non ADE Common Name Scientific Name Aji picante Capsicum spp. Algodon Gossypium barbadense Caimito Pouteria caimit o Carambola Averrhoa carambola Coco Cocos nucifera Guaba Inga edulis Guayaba Psidium guajava Limn Citrus aurantifolia Macambo Theobroma bicolor Malva Malva sp. Pacae Inga velutina Paico Chenopodium ambrosioides Pion negro Jatropha gossypifolia Sapote Quararibea cordata Shebn Attalea butyracea Soil Sample Number: DM 24 Non ADE Common Name Scientific Name Caimito Pouteria caimito Caa Saccharum officinarum Guaba Inga edulis Limn Citrus aurantifolia Mandarina Citrus reticulata Mango Ma ngifera indica Pijuayo Bactris gasipaes Pia Ananas comosus Shebn Attalea butyracea Zapallo Cucurbita maxima
81 Soil Sample Number: DM 22 Non ADE Common Name Scientific Name Aguaje Mauritia flexuosa Aji picante Capsicum spp. Algodon Gossypium bar badense Bolaina Guazuma ulmifolia Cacao Theobroma cacao Caimito Pouteria caimito Caoba Swietenia macrophylla Carambola Averrhoa carambola Cashu Anacardium occidentale Coco Cocos nucifera Cocona Solanum sessiliflorum Guisador Curcuma longa Hierbal uisa Cymbopogon citratus Kione Limn Citrus aurantifolia Malva Malva sp. Mango Mangifera indica Melon Cucumus sp. Mucuna Petiveria alliacea Naranja Citrus sinensis Pion negro Jatropha gossypifolia Sanango Tabernaemontana sp. Sandia Citrullus lanatus Shebn Attalea butyracea Taperiba Spondias dulcis Toronja Citrus paradisi
82 Soil Sample Number: NE 25 Non ADE Common Name Scientific Name Caimito Pouteria caimito Camote Ipomoea batatas Caa Saccharum officinarum Guaba Inga edulis Guaya ba Psidium guajava Huito Genipa americana Mango Mangifera indica Papaya Carica papaya Pia Ananas comosus Platano Musa sp. S andia Citrullus lanatus Shebn Attalea butyracea Manioc Manihot esculenta Soil Sample Number: NE 23 Non ADE Common Name S cientific Name Algodon Gossypium barbadense Almendra Terminalia catappa Cacao Theobroma cacao Caimito Pouteria caimito Coco Cocos nucifera Guaba Inga edulis Guayaba Psidium guajava Limn Citrus aurantifolia Mango Mangifera indica Maracuy Passifl ora edulis Pion negro Jatropha gossypifolia P latano Musa sp. Retama Spartium junceum Shebn Attalea butyracea
83 Soil Sample Number: NE 21 Non ADE Common Name Scientific Name Camote Ipomoea batatas Chiclayo Vigna unguiculata Guayaba Psidium guajava Pion blanco Jatropha curcas Platano Musa sp. Sandia Citrullus lanatus Tauri Couratari guianensis Manioc Manihot esculenta
84 Soil Sample Number: LJ 28 Non ADE Common Name Scientific Name A chiote Bixa orellana Aguaje Mauritia flexuosa Amasisa Er ythrina fusca Ayahuasca Banisteriopsis caapi Caimito Pouteria caimito Caa Saccharum officinarum Caoba Swietenia macrophylla Chacruna Psychotria viridis Choloque Sapindus saponaria Cormin Vitex pseudolea Guaba Inga edulis Guayaba Psidium guajava Huayruro Oromosia amazonica Huingo Crescentia cujete Ishpingo Amburana cearensis Mamey Syzygium jambos Mang o Mangifera indica Naranja Citrus sinensis Papaya Carica papaya Pion blanco Jatropha curcas Pion negro Jatropha gossypifolia S andia Cit rullus lanatus S angre de grado Croton lechleri Toronja Citrus paradisi Manioc Manihot esculenta
85 Soil Sample Number: LJ 28 Non ADE Common Name Scientific Name Algodon Gossypium barbadense Camote Ipomoea batatas Coco Cocos nucifera Granadilla Pas siflora ligularis Guaba Inga edulis Guayaba Psidium guajava Palma aceitera Elaeis guineensis Papaya Carica papaya Piri piri Cyperus articulatus Platano Musa sp. Sandia Citrullus lanatus Manioc Manihot esculenta
86 Soil Sample Number: SF 29 Non ADE Common Name Scientific Name Bolaina Guazuma ulmifolia Caimito Pouteria caimito Caa Saccharum officinarum Coco Cocos nucifera Guaba Inga edulis Guanbana Annona muricata Guayaba Psidium guajava Huayruro Oromosia amazonica Huingo Crescentia cujet e Limn Citrus aurantifolia Mango Mangifera indica Naranja Citrus sinensis Papaya Carica papaya Pij uayo Bactris gasipaes Pion blanco Jatropha curcas Pion negro Jatropha gossypifolia Platano Musa sp. Shebn Attalea butyracea T auari Couratari gui anensis Yarina Phytelephas macrocarpa Manioc Manihot esculenta
87 Soil Sample Number: SF 30 Non ADE Common Name Scientific Name Caimito Pouteria caimito Caoba Swietenia macrophylla Cedro Cedrela odorata Chacruna Psychotria viridis Coco Cocos nucif era Guaba Inga edulis Huayruro Oromosia amazonica Huito Genipa americana Papaya Carica papaya Pion negro Jatropha gossypifolia Platano Musa sp. Shebn Attalea butyracea Soil Sample Number: SF 32 Non ADE Common Name Scientific Name Aguaje Maurit ia flexuosa Anona Rollinia mucosa Caimito Pouteria caimito Camu camu Myrciaria dubia Cashu Anacardium occidentale Coco Cocos nucifera Guaba Inga edulis Guayaba Psidium guajava Limn Citrus aurantifolia Mandarina Citrus reticulata Palta Persea ame ricana Pia Ananas comosus Platano Musa sp. Sapote Quararibea cordata
88 Soil Sample Number: SF 31 Non ADE Common Name Scientific Name Coco Cocos nucifera Limn Citrus aurantifolia Pia Ananas comosus Shebn Attalea butyracea Tauari Couratari gui anensis Soil Sample Number: SF 34 Non ADE Common Name Scientific Name Achiote Bixa orellana Anona Rollinia mucosa Ayahuasca Banisteriopsis caapi Caimito Pouteria caimito Carambola Averrhoa carambola Cashu Anacardium occidentale Choloque Sapindus saponaria Coco Cocos nucifera Huayuro Oromosia amazonica Limn Citrus aurantifolia Mandarina Citrus reticulata Mango Mangifera indica Pia Ananas comosus Platano Musa sp. Sangre de grado Croton lechleri Shacapa Pariana radiciflora Shapaja Attalea phalerata Shebn Attalea butyracea Toronja Citrus paradisi Uvilla Pourouma cecropiaefolia Ua de gato Uncaria tomentosa
89 Soil Sample Number: SF 33 Non ADE Common Name Scientific Name Bolaina Guazuma ulmifolia Caimito Pouteria caimito Cashu An acardium occidentale Coco Cocos nucifera Guaba Inga edulis Guanbana Annona muricata Hierbaluisa Cymbopogon citratus Huingo Crescentia cujete Mango Mangifera indica Palma aceitera Elaeis guineensis Pia Ananas comosus Platano Musa sp. Sapote Quar aribea cordata Shacapa Pariana radiciflora
90 APPENDIX B SOIL SAMPLE ANALYSES
91 ADE soil characterization results Soil Sample Identification Salinity CEC Exchangable Cations Sum Sum % Sample Type pH (1:1) CaCO 3 Organic M atte r P K Ca +2 Mg +2 K + Na + Al +3 + H + of of Base ( 1:1 ) dS/m % % ppm ppm meq/100g Cations Bases Sat. SF 01 ADE 6.11 0.49 0.00 2.32 52.7 340 12.32 5.71 0.80 0.34 0.23 0.00 7.08 7.08 57 SJ 05 ADE 6.03 0.57 0.00 2.05 41.7 103 8.32 7 .19 0.80 0.18 0.15 0.00 8.32 8.32 100 SJ 06 ADE 4.38 0.39 0.00 1.02 3.8 31 3.68 2.14 0.20 0.05 0.09 0.10 2.58 2.48 67 SR 09 ADE 5.00 0.47 0.00 2.32 13.5 316 12.32 4.94 2.10 0.65 0.20 0.20 8.09 7.89 64 SR 10 ADE 5.15 0.71 0.00 2.80 22.1 221 10.08 4. 61 0.98 0.43 0.38 0.20 6.60 6.40 64 SR 12 ADE 5.36 0.51 0.00 2.53 10.5 153 8.80 5.26 1.43 0.29 0.08 0.10 7.16 7.06 80 NE 13 ADE 5.08 0.33 0.00 1.19 9.8 94 5.12 3.32 0.45 0.14 0.08 0.20 4.19 3.99 78 NE 14 ADE 6.10 0.43 0.00 2.12 18.6 188 7.36 6.04 0.88 0.34 0.10 0.00 7.36 7.36 100 SF 15 ADE 6.19 0.34 0.00 1.50 32.3 175 9.92 8.31 1.05 0.35 0.21 0.00 9.92 9.92 100 SF 17 ADE 6.28 0.32 0.00 1.78 29.5 210 10.40 8.31 1.17 0.37 0.13 0.00 9.98 9.98 96 SF 19 ADE 5.73 0.32 0.00 1.43 19.0 78 7.52 6.17 0.63 0.16 0.20 0.10 7.26 7.16 95 LJ 26 ADE 4.91 0.28 0.00 1.50 15.6 53 4.80 2.97 0.42 0.08 0.05 0.10 3.62 3.52 73 LJ 26 ADE 4.91 0.28 0.00 1.50 15.6 53 4.80 2.97 0.42 0.08 0.05 0.10 3.62 3.52 73 LJ 27 ADE 4.36 0.22 0.00 1.37 4.5 84 6.08 1.81 0.52 0.19 0.11 1.20 3.83 2.63 43 Average 5.40 0.40 0.00 1.82 20.7 149.9 7.97 4.98 0.85 0.26 0.15 0.16 6.40 6.24 78 Standard D eviation 0.67 0.13 0.00 0.54 14.0 96.97 2.82 2.14 0.49 0.16 0.09 0.31 2.42 2.56 18
92 Non ADE soil characterization results Soil Sample Identification Salinity CEC Exchangable Cations Sum Sum % Sample Type pH (1:1) CaCO 3 Organic Matter P K Ca +2 Mg +2 K + Na + Al +3 + H + of of Base ( 1:1 ) dS/m % % ppm ppm meq/100g Cation s Bases Sat. DM 20 Non ADE 4.31 0.27 0.00 0 .67 5.1 135 7.68 1.62 0.48 0.25 0.19 1.50 4.04 2.54 33 NE 21 Non ADE 4.63 0.11 0.00 0.41 2.5 45 4.80 1.41 0.42 0.08 0.08 0.70 2.69 1.99 41 DM 22 Non ADE 4.38 0.16 0.00 1.02 4.3 77 6.40 1.50 0.50 0.14 0.09 1.30 3.53 2.23 35 NE 23 Non ADE 4.75 0.19 0.00 0.75 5.7 62 5.76 1.86 0.57 0.13 0.12 0.60 3.28 2.68 47 DM 24 Non ADE 4.39 0.18 0.00 1.23 6.3 100 10.24 1.55 0.65 0.21 0.18 3.10 5.70 2.60 25 LJ 28 Non ADE 4.34 0.26 0.00 1.71 2.7 77 9.28 2.86 0.55 0.16 0.10 1.10 4.77 3.67 40 LJ 28 Non ADE 4.3 4 0.26 0.00 1.71 2.7 77 9.28 2.86 0.55 0.16 0.10 1.10 4.77 3.67 40 SF 29 Non ADE 5.12 0.27 0.00 1.30 6.1 95 8.80 5.00 1.23 0.21 0.08 0.10 6.62 6.52 74 SF 30 Non ADE 5.03 0.22 0.00 1.84 6.8 77 9.60 5.67 1.30 0.13 0.17 0.20 7.47 7.27 76 SF 31 Non AD E 5.26 0.15 0.00 0.75 3.4 106 4.32 1.57 0.48 0.18 0.12 0.20 2.56 2.36 55 SF 32 Non ADE 4.93 0.32 0.00 1.09 6.1 100 9.12 3.92 1.02 0.21 0.25 0.70 6.10 5.40 59 SF 33 Non ADE 4.64 0.20 0.00 1.43 3.8 37 6.72 2.61 0.63 0.08 0.17 0.40 3.89 3.49 52 SF 34 Non ADE 4.78 0.29 0.00 1.84 3.4 114 12.80 5.08 1.88 0.25 0.34 0.80 8.36 7.56 59 Average 4.68 0.22 0.00 1.21 4.5 84.77 8.06 2.89 0.79 0.17 0.15 0.91 4.91 4.00 49 Standard D eviation 0.33 0.06 0.00 0.48 1.6 27.42 2.40 1.54 0.44 0.05 0.08 0.79 1.83 2.00 1 5
93 Micronutreints and % Nitrogen Soil Sample Number Sample Type B ppm Cu ppm Fe ppm Mn ppm Zn ppm N % SF 01 ADE 0.4 3.8 561.5 5.6 22.3 0.13 SJ 05 ADE 0.3 3.1 588.0 6.6 16.8 0.07 SJ 06 ADE 0.1 1.5 199.0 8.4 2.5 0.07 SR 09 ADE 0.4 2.0 637.0 12.2 12.6 0.17 SR 10 ADE 0.6 1.4 757.0 6.0 5.6 0.10 SR 12 ADE 0.1 2.0 370.0 10.2 11.1 0.11 NE 13 ADE 0.4 1.2 113.0 6.7 9.3 0.06 NE 14 ADE 0.1 1.6 414.0 5.8 26.7 0.11 SF 15 ADE 0.4 3.2 468.0 6.2 14.2 0.10 SF 17 ADE 0.3 2.7 635.0 7.2 17.7 0.13 SF 19 ADE 0.3 2.6 500.0 3.9 8.1 0.08 LJ 26 ADE 0.1 1.2 550.0 5.7 7.4 0.06 LJ 26 ADE 0.1 1.2 550.0 5.7 7.4 0.06 LJ 27 ADE 0.4 1.3 1200.0 6.2 3.8 0.10 Average 0.3 2.1 538.8 6.9 11.8 0.10 Standard Deviation 0.2 0.9 256.3 2.1 7.1 0.03 DM 20 Non ADE 0.1 1.2 1300.0 9.1 10.5 0.07 NE 21 Non ADE 0.5 0.8 1520.0 6.4 3.8 0.04 DM 22 Non ADE 0.4 1.0 768.0 14.0 5.3 0.08 NE 23 Non ADE 0.3 0.8 646.0 5.8 5.6 0.10 DM 24 Non ADE 0.2 1.4 1310.0 7.2 8.2 0.08 LJ 28 Non ADE 0.2 1.5 1849.0 10 .8 4.8 0.07 LJ 28 Non ADE 0.2 1.5 1849.0 10.8 4.8 0.07 SF 29 Non ADE 0.3 1.3 518.0 10.5 10.9 0.07 SF 30 Non ADE 0.4 2.2 592.0 14.0 13.8 0.10 SF 31 Non ADE 0.0 1.0 270.0 7.3 5.9 0.05 SF 32 Non ADE 0.0 1.6 550.0 14.5 12.4 0.08 SF 33 Non ADE 0.0 1.1 621.0 8.1 9.6 0.06 SF 34 Non ADE 0.0 2.8 1222.0 13.9 21.8 0.11 Average 0.2 1.4 1001.2 10.2 9.0 0.08 Standard Deviation 0.17 0.57 532.63 3.15 5.02 0.02
94 APPENDIX C STATISTICAL ANALYSES Average Values P Values T test Dregrees of Fredom ADE Non ADE 5% B (ppm) 0.285714 0.185714 0.1276 1.5744 25.828 Cu (ppm) 2.057143 1.492857 0.06332 1.9473 23.955 Fe (ppm) 538.75 1027.286 0.005308* 3.1481 18.946 Mn (ppm) 6.885714 10.27143 0.002308* 3.4227 23.185 Zn (ppm) 11.82143 9.392857 0.3042 1.0504 23.459 N (%) 0.096429 0.078571 0.1042 1.6911 23.129 pH 5.399286 4.684615 0.00205* 3.56 19.137 Salinity (dS/m) 0.404286 0.221538 0.0002055* 4.59 18.662 Organic Matter (%) 1.816429 1.211538 0.004993* 3.079 24.951 P (ppm) 20.65714 4.530769 0.0008609* 4. 271 13.342 K (ppm) 149.9286 84.76923 0.0298* 2.41 15.213 CEC 7.965714 8.061538 0.9248 0.0953 24.81 Ca +2 (meg/100g) 4.981503 2.885385 0.007209* 2.94 23.612 Mg +2 (meg/100g) 0.846429 0.789744 0.7529 0.318 24.96 K + (meg/100g) 0.260806 0.168836 0.06774 1. 958 16.152 Na + (meg/100g) 0.148137 0.154013 0.8545 0.1853 24.79 Al +3 + H + (meg/100g) 0.164286 0.907692 0.006117* 3.1763 15.341 Statistically Significant P Values
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100 BIOGRAPHICAL SKETCH Elizabeth Gregg completed her undergraduate wo rk in biology with emphasis in plant s cience at the University of California, Santa Cruz in 2002. Her research experience at UC Santa Cruz included an independent research project in pollination biology in Monteverde, Co sta Rica. She has experience working in both cultural and natural resources management. Shortly after completing her undergraduate work she took a job working in Hawaiian archaeology where she conducted surveys and wrote reports for three years. After spen ding some time volunteering with small farmers in Costa Rica, she returned to California to work for the US Forest Service as the botany crew leader for four year s. She began pursuing a Master of Science degree at the University of Florida in 2010.