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1.This document is HS 746, one of a series of the Horticultural Sciences Department, Florida C ooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Date first printed: April 1998. Please visit the EDIS Web site at http://edis.ifas.ufl.edu .The Institute of Food and A g ricultural Sciences is an equal opportunit y /affirmative action emplo y er authorized to provide research, educational information and other services onl y to individuals and institutions that function without re g ard to race, color, sex, a g e, handicap, or national ori g in. For information on obtainin g other extension publications, contact y our count y Cooperative Extension Service office. Florida Cooperative Extension Service / Institute of Food and A g ricultural Sciences / Universit y of Florida / Christine Ta y lor Waddill, Dean2.J. J. Ferguson, professor, Horticultural Sciences Department; and G. D. Israel, professor, Program Development and Evaluation Center, Agricultural Education and Communication Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida Gainesville, 32611.HS 746Citrus Irrigation Methods and Water Sources: a 1996 Survey1 J. J. Fer g uson and G. D. Israel2Although a major freeze has not affected the Florida1, 000 acres. Ownership and management patterns citrus industry since 1989, growers on nonbedded orincluded growers who owned but did not manage their Ridge groves indicated in a 1992 survey that coldgroves (owners only), those who owned and managed their protection was their third most important information needown groves (owners/managers), caretakers who managed after pest management and cost-effective chemicals.the groves of others (manages others), and those who both Growers on bedded groves also ranked cold protectionowned their own groves and managed the groves of others ninth out of 17 items. A moderate freeze in the 1995-96(manages both). In add ition, cold-protection practices season further emphasized the need to document currentwere compared within production systems, production cold-protection and related irrigation practices, includingregions, management patterns, and grove size. In some irrigation methods and water sources.cases, growers could choose more than one response; in A mail survey was conducted in 1996, obtaining aor no answer were combined into one graph, resu lting in sample population of 674 citrus growers from the ma ilingwhat appears to be a greater than 100% response. "N" lists of extension agents in 27 Florida counties wherevalues indicate the number of respondents answering a citrus was commercially grown. Of the mailed surveys,question. 451 useable responses were returned (66% response rate), with an expected sampling error of 4% at the 95% level. Data were analyzed on five different levels: 1) statewide (27 counties), 2) planting system, 3) production region, 4) grove size, and 5) management pattern. Planting system referred to groves that were bedded (primarily poorly drained, shallow soils in the Indian River area and southwest Florida) and nonbedded (primarily the deeply drained, sandy soils of the Ridge). Production regions included the central Florida Ridge, the Indian River area (east coast of Florida), southwest Florida, west Florida, and a multic ounty category that included respondents with groves in more than one county. Data were also analyzed in terms of grove size: 1-25 acres, 26-49 acres, 50-99 acres, 100-499 acres, 500-999 acres, and greater than other cases, data from a series of questions requiring a yesIndustry CharacteristicsWhen the distribution of survey respondents was considered, the largest percentage of respondents were located on the Ridge (41%), followed by the Indian River area (26%), 10% in southwest Florida, and 19% in west Florida. Only 3% of respondents fell into the mu ltic ounty category. When asked about management patterns, the greatest percentage of growers (58%) indicated they were both owners and managers, with 18% and 16% saying they managed the groves of others and managed both their own groves and those of others, respectively. Only 8% said they were owners only. Fifty-eight percent indicated they produced citrus on bedded groves, and 42% on
Citrus Irri g ation Methods and Water Sources: a 1996 Surve y Pa g e 2April 1999 Figure 1. Citrus irri g ation methods statewide. Figure 2. Irri g ation methods and production re g ions statewide. Figure 3. Irri g ation methods and g rove size statewide.nonbedded groves. These data were similar to those reported for groves in bedded (504,291 acres or 58%) and nonbedded ( 350,620 acres or 42%) counties in the 1996 Commercial Citrus Inventory. On a statewide basis, 30% of surveyed growers indicated their groves were less than 49 acres, with 25% each saying their groves were in the 99 to 499 and greater than 1,000 acre range. Thirteen percent had groves from 49 to 99 acres, and 7% had groves from 499 to 999 acres.Irrigation MethodsWhen questioned about irrigation systems statewide, 88% of growers said they used microsprinkler systems (compared with 73% in 1989), 16% used drip (20% in 1989), 13% used fl ood/seepage (16% in 1989), 12% used permanent overhead (23% in 1989), and 4% used portable or self-propelled guns (10% in 1989) (Fig. 1). Surprisingly, 19% said they used no irrigation (12% in 1989), and 1% used other met hods.Irrigation Methods within Production SystemWhen irrigation methods within production systems were considered, microsprinkler irrigation was the most commonly used method by growers on both production systems (88%). Bedded growers also used drip (25%), flood/seepage (22%), and overhead systems (10%), with 18% using no irrigation. Nonbedded growers used drip (4%), flood/seepage (1%), and overhead (16%) systems, with 20% using no irrigation. Irrigation Method within Production RegionWithin production regions microsprinkler irrigation was the most commonly used system (74 to 100% of respondents) (Fig. 2). Within the Ridge, approximately 25% of growers said they used permanent overhead systems or no irrigation system at all. In the Indian River area, flood/seepage was the second most common (36%), whereas in southwest Florida, drip was the second most common system (26%). In west Florida, drip and no irrigation were mentioned by approximately 15% of growers. Multic ounty growers also used drip as their second choice (54%). Irrigation within Grove SizeInformation was also obtained according to grove size. Microsprinkler irrigation was the most common method (76 to 97%) on groves of all sizes statewide (Fig. 3). Drip irrigation was most common on large groves, with 23% of respondents with groves from 500 to 999 acres and 31% with groves greater than 1,000 acres indicating they used drip irrigation. Flood/seepage was used by 29% of growers with groves greater than 1,000 acres.Irrigation Methods within Manag ement Pattern When survey data were analyzed according to management pattern, microsprinkler irrigation was by far the most common method used (86 to 99%) (Fig. 4). Of those who did not irrigate, the highest percentage were those that managed both their own groves and those of
Citrus Irri g ation Methods and Water Sources: a 1996 Surve y Pa g e 3April 1999 Figure 4. Irri g ation methods and mana g ement pattern statwide. Figure 5. Source of irri g ation water statewide.others (45%). Drip irrigation (approximately 27%) and flood/seepage (approximately 22%) were used most frequently by those who managed the groves of others and both their own groves and those of others. Water SourceOn a statewide basis, 77% of growers obtained their water from deep wells (compared to 78% in 1989), 37% from surface water (compared to 25% in 1989), and 13% from shallow wells (compared with 10% in 1989) (Fig. 5). Other sources cited were reclaimed water and spider-web wellsa manifold of linked, shallow wells. When data were analyzed primarily in terms of water source and secondarily in terms of grove size, 31% of those with groves less than 50 acres and groves greater than 1,000 acres obtained their irrigation water from surface water. Thirty-three percent of growers with groves less than 50 acres, 27% of growers with groves from 100 to 499 acres, and 19% of those with groves greater than 1,000 acres obtained water from wells deeper than 100 feet deep. Shallow wells were used primarily by those with groves less than 50 acres (53%).Water Source wit hin Production SystemsWhen irrigation water sources for bedded and nonbedded groves were considered, 77% of growers on both production systems used deep wells. Forty-five percent of growers on bedded groves also cited surface water sources (compared to 39% in 1989) and shallow wells as water sources, whereas 26% of growers on nonbedded groves used surface water (compared to 15% in 1989), and 10% used shallow wells. When grove size was considered, the highest percentage of growers on bedded groves who used surface water were those with groves greater than 1,000 acres (43%), and the highest percentage of growers on nonbedded groves who used surface water were those with groves less than 50 acres (73%). Deep wells were used most commonly by bedded growers with small, medium, and large groves: <50 acres, 22%; 100-499 acres, 27%; >1,000 acres, 29%. However, a much higher percentage of nonbedded growers with groves less than 50 acres (48%) used deep wells. For both bedded (45%) and nonbedded growers (73%), shallow wells were used most commonly by growers with groves less than 50 acres.Water Source wit hin Production Regions Considering water source within production region, deep wells were the major source of irrigation water in all production regions (65 to 86%) except the Indian River area, where surface water was the major source (65%). When irrigation water sources were examined within production region in terms of grove size, surface water was used most frequently by Ridge growers with groves less than 50 acres (60%) and by Indian River (36%), southwest Florida (57%), and multic ounty (67%) growers with groves greater than 1,000 acres. Deep wells were used most commonly by Ridge and Indian River growers with groves less than 50 acres and 100 to 499 acres and by southwest Florida (47%) and multic ounty (46%) growers with groves greater than 1,000 acres. Shallow wells were used most frequently by Ridge and Indian River growers with groves less than 50 acres and from 100 to 499 acres and by southwest Florida growers with groves greater than 1,000 acres (47%).
Citrus Irri g ation Methods and Water Sources: a 1996 Surve y Pa g e 4April 1999Water Source wit hin Grove Size When data were analyzed primarily in terms of grove size and secondarily in terms of water source, deep wells were the major water source for groves of all sizes (62 to 87% of respondents). When grove size increased, so did the percentage of growers using surface water, with 16% of growers with groves from 1 to 25 acres, 35% of those with groves from 100 to 499, acres and 66% of those with groves greater than 1,000 acres using surface water, primarily in southern Florida. Shallow wells were the least commonly used water source, with 10 to 15% of growers mentioning this source. Water Source wit hin Manag ement PatternDeep wells were also the major water source for growers with different management patterns (70 to 90%). However, 53% of those who managed others groves and both managed their own groves and those of others said they also used surface water. When water source by management pattern was examined in terms of grove size, 83% of owners only and 45% of owners/managers used surface water on groves less than 50 acres. In contrast, surface water was used by 56% of those who managed others groves and 45% of those that manage both their own groves and those of others on groves greater than 1,000 acres. Similar patterns were detected for those who used deep wells. Shallow wells were used most frequently by owners only and owners/managers on groves less than 50 acres, by 31% of those that managed others groves on groves from 100 to 499 and greater than 1,000 acres. Those who managed both their own groves and those of others used shallow wells most commonly on groves from 100 to 499 acres. ConclusionEighty-eight percent of growers said they used microsprinkler irrigation systems (up from 73% in 1989), with the use of drip and flood/seepage remaining approximately the same and the use of permanent overhead and portable guns decreasing. Microirrigation was used by bedded growers more on midand large-sized groves and by nonbedded growers more on smalland mid-sized groves, reflecting the distribution of groves of different sizes within these production systems. After microirrigation, flood/seepage irrigation was most commonly used in the Indian River area, especially on large groves, and drip was most commonly used in southwest Florida, especially on midand large-sized groves. Growers with less than 50 acres in all production regions under all types of management were the most likely not to irrigate at all. Deep wells were the major source of irrigation water, followed by surface water and shallow wells. Bedded growers with large groves and nonbedded growers with small groves were the most likely to use surface water, as were owners and owners/managers on small groves.