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.' .f j
Agronomy Research Report: AY-89-05
On-Farm Crop Nutrition Investigation of Perennial
Peanut Under Low Management
R. W. Rice (1), R. N. Gallaher (2), E. C. French (2),
and J. Kisakye (1); (1) Graduate Students and (2)
Professor and Associate Professor, respectively,
of Agronomy, Institute of Food and Agricultural
Sciences, Department of Agronomy, University
of Florida, Gainesville, FL 32611 '- ..
The 'Florigraze' cultivar of perennial peanut (Aracqhis
qlabrata Benth.) holds promise as a drought and pest resistant,
high-quality forage crop suitable to well-drained sandy soils of
Florida. Florigraze was established on a Grossarenic Paleudult
in February 1986. In September 1988, the stand displayed
sporadically distributed patches of deficiency symptoms. Leaves
on unhealthy plants were chlorotic, especially at the tip and
along the outer edges, with necrosis in the more severely -
affected plants. Leaf, stem and rhizome dry matter accumulation
was sharply reduced in deficient plants. Relative to published
recommended leaf nutrient concentrations for Arachis hypogaea, N
and P were mildly deficient in both healthy and deficient plant
leaves while K was present in very low concentrations. Soil
extractable K was 13 and 9.5 mg kg' in areas with healthy and
deficient looking plants, respectively. The most limiting
nutrient appeared to be K, based on phenotypic symptoms and
tissue and soil analysis.
DESCRIPTION OF THE PROBLEM
A stand of perennial peanut (Arachis glabrata Benth.)
cultivar 'Florigraze' displayed irregular, sporadic patches of
unhealthy plants. Unhealthy phenotypic characteristics included
interveinal chlorosis at leaf tips and along outer leaf margins.
Some plants suffered a general yellowing over the entire foliage.
Younger, terminal leaves projected green veins against bleached -
interveinal tissue. In general, unhealthy plants were marked by
shorter internodes and smaller leaves.
Florigraze is a warm season rhizoma peanut well suited for
moderately-well to extremely well-drained soils. Its perennial
growth characteristics, resistance to disease and drought, and
production of high quality forage for both hay and grazing make
this legume a particularly promising crop for Florida.
A pre-plant (generally January early March) 336 kg ha-
application of 0-10-20 (N-P2Os-K O) or 0 kg N ha 14.7 kg P ha1
, and 56 kg K ha'1 followed by the same application in early
August has been recommended for the initial establishment (Prine
et al., 1981). Soil pH ranging from 5.8 to 6.5 and soil test Ca
and Mg levels of 0.27 g kg'1 and 0.03 g kg-1 respectively, are
also recommended by the same authors. A recent study suggests
that a lower soil pH near 5..5 favors establishment and growth
and concludes that liming should not be administered as a pre-
plant treatment (Niles, 1987).
Early field studies on the perennial peanut selection 'GS-1'
(Gainesville Selection No. 1) conducted on an Arredondo fine sand
determined that N fertilization should be avoided during the
establishment of GS-1. Sixteen months after planting rhizome mat
fragments of size 0.093 m2, a fertilizer control treatment of 0
kg N ha-1 produced a final coverage of 12.5 m With N
application rates of 168 kg N ha and 336 kg N ha' coverage
decreased to 8.8 m2 and 5.2 m respectively. Dry matter hay
yields were highest for the control plot at 4460 kg ha ,
decreasing to 2680 kg ha"1 and 1710 kg ha"' for the respective N
rates (Adjei et al., 1976).
Different post-plant treatments including herbicide
application, herbicide and digitgrass (Digitaria decumbens)
introduction and weed fallow did not produce any significant
differences in spread when 0 kg N ha was applied. The same
treatments concurrent with N applications produced significant
decreases in coverage over a 13 month period. In a greenhouse
study, Adjei and Prine (1976) found that increasing levels of N
greatly reduced nodule formation and development. The N
concentration of forage top growth was not influenced by higher N
fertilizer applications. The GS-1 selection was later released-
as the Florigraze cultivar.
In a comparative study between various perennial peanut
cultivars, Prine (1973) measured ranges of N, P, K, Ca and Mg
concentrations in Florigraze forage over a 5 yr period. Highest,
average and lowest nutrient concentrations expressed in g kgI
for individual nutrients were N: 28.6, 22.4, 18.8; P: 3.2, 2.8,
2.4; K: 24.5, 17.4, 12.5; Ca: 19.8, 15.2, 13.0; and Mg: 6.8, 4.7,
2.5. Essential element sufficiency ranges for upper mature leaf
tissue (taken before or at bloom stage) for A hypoqaea were
reported as N (35 45 g kg''), P (2.5 5.0 g kg ), K (20 30 g
kg-1), Ca (12.5 20 g kg 1), Mg (3 8 g kg'1), Fe (50 300 mg
kg'1), Mn (50 350 mg kg ), and Zn (20 50 mg kg ), where
concentrations are relative to one kg of dry leaf tissue (Jones,
Data on average and highest seasonal uptake of N, P, K, Ca
and Mg indicated that perennial peanuts have high nutrient
requirements. The highest uptakes for Florigraze over a 4 yr
study were 280 kg N ha'1, 35 kg P ha'1, 230 kg K ha"', 180 kg Ca
ha"1 and 60 kg Mg ha'. These figures demonstrate uptake values
for high forage production. In this study, Florigraze stands
were fertilized twice at the individual rate of 560 kg ha1' of 0-
4.2-16.6 (NPK), providing 0 kg N ha'1, 47 kg P ha"1, and 188 kg K
ha"' during the season. Since this application rate accounted
for only 82% of the highest K uptake values, Florigraze was
exploiting the soil system for additional K (Prine, 1973).
In a recent on-farm trial study (Niles, 1987), multiple
regression analysis indicated that low soil pH favorably
influenced establishment and growth of Florigraze. A trend was
observed associating previously uncultivated (and unlimed) fields
with higher Florigraze populations; the greatest plant population
occurred in a soil with pH 5.5. Extractable soil Al and K were
also associated with good growth, the former a reflection of
lower soil pH (Niles, 1987).
Lack of response in established stands to both P and K
fertilization may be due to a combination of deep rooting and
sod-forming rhizoma which can efficiently exploit the nutrient
pool in relatively nutrient-poor soils. Results from a number of
different studies collectively suggest that Florigraze often
shows little response to fertilizer. Three yr average dry matter
forage yields of Florigraze with no applied fertilizer were 10.3
t ha.. Application of 0 kg N ha ', 24.5 kg P ha'I and 150 kg K
ha'1 produced 10.5 t ha'1 while an application of 0 kg N ha 1, 49
kg P ha'1, and 290 kg K ha'1 produced a corresponding dry matter
yield of only 11..2 t ha'1 (Prine et al., 1986). Soil test
nutrient levels were not reported.
The objectives of this study were 1) to examine macro- and
micro-nutrient concentrations in leaf tissue from three different
positions along the main stem of the peanut plant (terminal,
middle and lower positions corresponding to younger, mid-age and
older leaves) in order to assess if an essential element
deficiency existed and 2) to examine soil pH and extractable
soil nutrient concentrations to see if these soil parameters were
associated with the observed unhealthy foliage that was
symptomatic of a nutrient deficiency.
MATERIALS AND METHODS
A stand of Florigraze perennial peanut in Gilchrist County,
Florida was selected for study. Rhizomes were planted with a
Bermuda King Sprig planter in February, 1986 at a rate of 0.15 m
ha'1 with 0.5 m row spacings. Tillage included bottom plowing
and two passes with a disc harrow over the long-term fallow
population of wiregrass (Aristida stricta) and bahiagrass
(Paspalum notatum L. Fluggi) that had covered the field for many
years prior to the Florigraze introduction. No fertilizer, lime,
herbicide, insecticide, nematicide or irrigation were applied at
or subsequent to planting. The soil was a sandy, silicious,
hyperthermic, Grossarenic Paleudult, also known as an Arredondo
fine sand. Plant and soil sampling was undertaken when the crop
was 0.30 m high before the 1988 season's first cutting for hay.
A randomized complete block design was used with five
replications of two treatments identified as 1) Healthy plants
displaying phenotypic nutrient sufficiency symptoms and 2)
Unhealthy plants displaying phenotypic nutrient deficiency
symptoms. Entire plants and their rhizome mats were removed from
a 0.25 m2 area containing either healthy or unhealthy looking
foliage. Leaves within each plant treatment replication were
sampled from three different locations along the main stem;
bottom (oldest) leaves, middle (mid-age) leaves and terminal
(youngest) leaves. Thus a total of 30 leaf samples were
obtained. Soil samples were taken from the 0-0.15 m depth
increment for each plant treatment replication for a total of 10
soil samples. Samples were also separated into leaf, stem and
rhizome for individual tissue analysis. For N and mineral
analysis, soil samples were air dried, sifted through a 2-mm
stainless steel mesh (to avoid Fe contamination), well mixed and
stored in air-tight bags. Leaves, stems and rhizomes were
vigorously rinsed in water, dried at 70 oC, ground through a
Wiley Mill fitted with a 1-mm stainless steel screen, redried to
remove accumulated moisture during grinding and stored in air-
Soil N Analysis
A 2.0 g sample was vortexed in a 100 ml Pyrex test-tube
under a hood with 3.2 g of prepared catalyst (9:1 K2SO, :CuSO4)
and 10 ml of H2SO4, loaded onto an aluminum digester block
(Gallaher, 1975) and digested at 370 oC for 210 minutes. To
reduce frothing, 2 ml 30% H202 was added in small increments
during the initial digestion period. Tubes were capped with
small funnels, allowing evolving gases to escape while preserving
reflexing action. Cool digested solutions were vortexed with
approximately 50 ml of deionized water, allowed to cool for two .
hours, brought to a 75 ml volume, transferred to square Nalgene
storage bottles (sand residue was filtered out), sealed, mixed
and stored. Nitrogen was analyzed on a Technicon Autoanalyzer
II system (manifold, colorimeter) linked to an automatic
Technicon Sample IV (solution sampler) and an Alpken Corporation
Proportioning Pump III; N was trapped as NH4SO4. A 0.100 g of
prepared laboratory plant sample with a long history of recorded
N concentration values was subjected to the same procedure and
used as a check.
Soil Mineral Analysis
Soil samples were extracted by a double acid procedure
(Mehlich, 1954) and analyzed by the IFAS Extension Soil Testing
Laboratory on their Inductively Coupled Argon Plasma Soil
Analyzer (ICAP). Phosphorus was determined by colorimetry, K by
flame emission and Ca, Mg, Cu, Mn, Fe, Zn and Al by atomic
Plant N Analysis
The procedure was identical to soil N analysis except 0.100
g of plant sample was used and two glass beads were introduced to
the digestion tubes to attenuate violent frothing. The
laboratory control sample was also used as a check.
Plant Mineral Analysis
Exactly 1.00 g of plant sample was weighed into 50 ml
beakers. Samples were ashed in a muffle furnace at 4800C for
approximately six hours. Cool ash contents were carefully
saturated with 10 ml deionized H20, mixed with 2 ml of
concentrated HC1 and gently boiled to dryness on a hot plate.
This water/acid procedure-was repeated, dried residue was
suspended in deionized H20, and brought to a 100 ml volume for a
solution strength of 0.1 N HC1. Solutions were sent to the IFAS
Extension Soil Testing Laboratory for P (colorimetry), K (flame
emission), and Ca, Mg, Cu, Mn, Fe and Zn (atomic absorption)
concentration analysis on a Perkin-Elmer Atomic Absorption
RESULTS AND DISCUSSION
Dry Matter and Leaf Nutrient Analysis
Large differences in tissue dry matter production between
healthy and unhealthy plant populations existed. Plants
displaying nutrient sufficiency characteristics (healthy)
produced almost 200% more leaf and 83% more rhizome dry matter
than did unhealthy plants. Stem dry matter production was
statistically similar for both treatments. In terms of palatable
forage (stems and leaves), healthy plants provided a
substantially higher forage mass per unit area (Table 1).
Examination of macro-nutrient concentrations in leaf tissue
provides some plausible explanations for the observed deficiency
symptoms. Nitrogen, P, Ca and Mg concentrations were similar for
both healthy and unhealthy plants. The steady trend of
increasing N concentrations with progressively younger leaf
tissue (from lower to middle to terminal leaves) reflects this
element's status as a mobile nutrient, readily translocated from
older tissues to younger, more distal growth (Table 2). While
terminal leaf tissue N concentrations for both healthy (23.7 g N
kg'1) and unhealthy (22.3 g kg"') were well below the sufficiency
range for A. hypogaea (35-45 g kg') reported by Jones (1974),
these values were very similar to average N concentrations of
overall A. qlabrata Benth. forage reported by Prine (1973) (Fig.
1). Terminal leaf P concentrations were slightly deficient for
both treatments with respect to A. hypoqaea sufficiency ranges
and were below both the average (2.8 g kg ) and lowest (2.4 g
kg'1) concentrations for Florigraze forage (lowest concentrations
are not graphed). Observed deficiency symptoms did not suggest a
Terminal leaf Ca concentrations decreased steadily in both
healthy and unhealthy plants with decreasing age of the leaf, an
expected trend for an element considered immobile (Table 2).
Calcium concentrations were within the A. hypoqaea sufficiency
range. Leaf Mg concentrations along the three different
positions on the main stem did not follow any clear pattern that
might reflect this nutrient's status as a mobile element (Table
2). Magnesium accumulated in large quantities in both treatments
across all three leaf positions, slightly exceeding the
sufficiency range given by Jones (1974) and substantially
exceeding the average forage Mg concentrations measured by Prine
Increasing K concentrations with progressively younger leaf
growth in healthy plants reflects the normal uptake of a mobile
element. Although unhealthy plants followed the same trend, the
concentrations were significantly smaller than that observed in
healthy plants for all three leaf positions. Terminal leaf K
concentrations in healthy leaves were 54% greater than the
corresponding data for unhealthy plants. Relative to the A.
hypoqaea sufficiency range for terminal leaf tissue (20-30 g K
kg ), both treatments were very deficient. Potassium
concentration in healthy leaves was only 26% of the lower
critical value while unhealthy leaf K concentration was only 17%
of the 20 g K kg"1 critical value. Potassium concentrations in
healthy and unhealthy leaves were 30% and 20%, respectively, of
the average (17.4 g K kg ') forage K concentration reported by
Prine (1973). Given that leaf K levels were very low in both
treatments, it is not immediately apparent why some parts of the
stand displayed phenotypic signs characteristic of nutrient
sufficiency. Unhealthy plants did display foliage chlorosis
patterns typical of a K deficiency. Unusually high Mg contents
in both treatments across all three leaf positions displayed no
differential accumulation trends relative to leaf age. This
pattern may imply an accelerated uptake of the Mg2 cation as a
response to severely depressed uptake of the Ke monovalent
Micro-nutrient concentrations did not differ between healthy
and unhealthy plants (Table 3). Terminal leaf concentrations of'
Fe, Mn and Zn were within sufficiency ranges reported for A.
hypogaea (Fig. 3). Sufficiency range for Cu was not reported
A comparison of nutrient concentrations in healthy and
unhealthy leaf, stem and rhizome tissue showed no significant
differences for N, P, Ca, Mg, Cu, Mn and Zn. Only K and Fe
differed significantly between healthy and unhealthy plants.
Potassium was lower and Fe was higher in the unhealthy plant
tissue (Tables 4, 5).
No significant differences were found for extractable soil
plant nutrient values between soils supporting healthy and
unhealthy plants (Table 6). With respect to the current average
recommendations by the IFAS Extension Soil Testing Laboratory for
agronomic crops, a "medium level" for extractable P and Mg is
assigned to the range of 0.015-0.030 g P kg"' soil and 0.015-
0.030 g Mg kg'I soil. A "very low" category for soil K is
assigned to extractable K levels less than 0.02 g K kg' soil.
In this study, soil extractable K levels for both healthy and
unhealthy treatments would be considered "very low" (Table 6).
The Laboratory's recommendations are not tailored for individual
crops but are averages for all agronomic crops. "Very low"
extractable K is thus somewhat ambiguous and subsequent decisions
on fertilization or management strategies should be supported by
other measured parameters such as dry matter production and plant
nutrient levels. Since terminal leaf tissue K levels were
considered very deficient relative to sufficiency ranges
developed for A. hypoqaea and were substantially lower than
reported levels in healthy Florigraze forage, the conclusion of
this study is that a K deficiency was in affect.
Extractable soil Al, percent organic matter and soil pH were
similar across both treatments. The soil pH of about 5.7 was
typical for these weathered, mineral soils and was not considered
a detrimental factor, based on previous studies (Prine et al.,
1981; Niles, 1987).
1) Based on nutrient analysis of terminal leaf tissue,
extractable soil K concentrations and comparisons of nutrient
levels in leaf, stem and rhizome, the Florigraze stand was
suffering from a K deficiency.
2) Since healthy looking plants were also associated with low K
values for the above parameters, the implication may be that
Florigraze can tolerate much lower soil and tissue K
concentrations relative to Arachis hypogaea.
3) Nitrogen, P, Ca, and Mg concentrations for leaf tissue were
similar for both healthy and unhealthy plants. With the
exception of Fe, micro-nutrient concentrations in leaf tissue did
4) The field should receive a fertilizer amendment. Current
recommended fertilizer rates for the initial establishment of
perennial peanut would supply 112 kg K ha"1 in a split
1. Adjei, M.B., and G.M. Prine. 1976. Establishment of
perennial peanuts (Arachis glabrata Benth.). Soil and Crop Sci.
Soc. Fla. Proc. 35:50-53.
2. Gallaher, R.N., C.O. Weldon, and J.G. Futral. 1975. An
Aluminum block digester for plant and soil analysis. Soil Sci.
Amer. Proc. 39(4):803-806.
3. Jones, J.B. Jr. 1974. Plant analysis handbook for Georgia.
Coop. Ext. Work in Ag. Home Econ. University of Georgia, College
of Ag. Bull. 735.
4. Mehlich, A. 1953. Determination of P, Ca, Mg, K, Na and NH4.
North Carolina Soil Test Division (Mimeo, 1973). North Carolina
State University, Raleigh, NC.
5. Niles, W. 1987. Effect of fertilizer, lime, phosphorus,
potassium, magnesium and sulfur on the establishment of
Florigraze, (Arachis glabrata Benth.). M.S. Thesis. University of
Florida, Gainesville, FL.
6. Prine, G.M. 1973. Perennial peanuts for forage. Soil and Crop
Sci. Soc. Fla. Proc. 32:33-35.
7. L.S. Dunavin, J.E. Moore and R.D. Roush. 1981.
'Florigraze' rhizoma peanut, a perennial forage legume.
University of Florida Ag. Exp. Sta. Circ. S-275.
8. -- __ R.J. Glennon and R.D. Roush. 1986. Arbrook
rhizoma peanut, a perennial forage legume. University of Florida
Ag. Exp. Sta. Circ. S-332.
Table 1. Dry matter yield of three Perennial peanut plant
tissues as affected by relative health of plants.
Plant Phenotypic status of above-ground foliage
type Healthy Unhealthy Mean
"------ --- ~------ --- Cg/m -----*-----"*---------
Leaf 135.31 b + 45.42 b 90.36
Stem 87.75 c 42.23 b NSi 64.99
Rhizome 378.28 a 206.48 a 292.38
Mean 200.45 98.04
*, NSi Means within subtreatment (plant tissue) rows
followed by or NSi are significantly different
(Duncan's NMRT) at p=0.05 or not significant,
respectively, for plant status in a 2-way inter-
action between subtreatments and main treatments
+ Means within main treatment columns not followed
by same letter are significantly different for
plant tissue in a 2-way interaction between sub-
treatments and main treatments.
Table 2. Macro-nutrient concentrations in Perennial peanut leaf
tissue as affected ,y relative health of plant: and by
position of leaf along main stm of plant.
Leaf position Phen.typic status f above-cro'un f oliag
along main -.------------------------
plant stem Healthy Unhealthy Mean a
------------- ------------------------------ ------- ---------
L L i3. 4i % -.
Terminal 23.74 22.32 23.03 a
Middle 22.04 21.28 21.66 b
Lower 18.78 18.12 18.45 c
Mean 21.52 20.57 NS
Terminal .2.34 2.26 2.30 a
Middle 2.34 2.18 .2.26- a
Lower 2.38 2.24 2.31 a
Mean 2.35 2.23 NS
Terminal 5.28 a @ 3.42 a & 4.35
Middle 3.66 b 2.50 b 3.08
Lower 3.04 c 2.22 b 2.63
Mean 3.99 2.71
Terminal 15.44 17.32 16.38 c
Middle 19.16 20.82 19.99 b
Lower 23.18 24.90. 24.04 a
Mean 19.26 '21.01 NS
Terminal 8.46 b 8.40 b NSi 8.43
Middle 9.00 a 8.56 b NSi 8.78
Lower 8.72 b 8.94 a NSi 8.83
Mean 8.73 8.63
NS Main treatment (plant status) means not significant (F-test)
+ Subtreatment (leaf position) means not followed by same letter
are significantly different (Duncan's NMRT at p=0.05.
S..Means within main-treatment columns .not followed by same. letter
are significantly different (Duncan's NMRT) at p=0.05 for leaf
position in a 2-way interaction between subtreatments and
& Means within subtreatment rows followed by or NSi are signi-
ficantly different (Duncan's NMRT) at p=0.05 or not significant
respectively, for plant status in a 2-way interaction between
subtreatments and main treatments.
Table 3. Micro-nutrient concentrations in Perennial eanu- leaf
tissue as affected by relative health of plants and by
position of leaf along main stem of plant.
Leaf position Phenczyc status of above-ground- fiage
along marin ------------------- --------
plant stem Healthy --I- .. ..-a
- -- -- -- -- - - - - -.r --^- -- - I -
Terminal 11.8 17.4 14.5 a
Middle 15.5 12.6 14.1 a
Lower 10.0 12.6 11.3 a
Mean 12.5 14.2 NS
Terminal 76.0 74.0 75.0 a
Middle 70.0 68.0 69.0 a b
Lower 62.0 58.0 65.0- b
Mean 69.3 70.0 NS
Terminal 61.6 73.2 67.4 b
Middle 79.0 86.8 82.9 a
Lower 85.0 88.4 86.7 a
Mean 75.2 82.8 NS
Terminal 26.8 27.2 27.0 a
Middle 24.4 22.6 23.5 a
Lower 19.4 24.8 22.1 a
Mean 23.5 '24.9 NS
NS Main treatment (plant status) means not significant (F-test)
+ Subtreatment (leaf position) means hot followed by same letter
are significantly different (Duncan's MRT) at p=0.05.
Table 4. Macro-nutrient concentrations of 3 major tissue -tyes of
Perennial peanut in plants withdifferent health status
based on phenotypic condition of above-ground foliage.
- - - - - - - - - -
Plant Phenotypic status of above-ground folia
type Healthy Unhealthy Mean +
--- --------------, -- / -
Leaf 22.52 21.82 22.17 a
Stem 11.36 13.54 12.45 b
Rhizome 20.34 21.38 20.86 a
Mean 18.07 18.91 NS
Leaf 2.47 2.38 2.2 a
Stem 2.28 2.24 2.25 a
Rhizome 1.78 1.58 1.68 b
Mean 2.18 2.07 NS
Leaf 2.62 1.76 2,.19 a b
Stem 2.26 1.46 1.86 b
Rhizome 2.52 2.12 2.22 a
Mean 2.47 1.78 *
Leaf 21.38 .20.88 21.1 a
Stem 9.82 10.06 9.94 b
Rhizome 6.58 5.92 5.25 c
Mean 12.59 12.29 NS
Leaf 9.32 8.80' 9.06 a
Stem 7.14 7.58 7.36 b
Rhizome 2.54 2.42 2.48 c
Mean 6.33 6.27 NS
-'*; NS- Main treatment (plant status) means are significantly dif-
ferent (F-test) at p=0.05 or not significant, respectively.
+ Subtreatment (tissue type) means not followed by same
letter are significantly different (Duncan's NMRT. at p=0.05.
Table 5. Micro-nutrien concentrations of 3 major tissue types of
Perennial peanut in plants with different health status
based on phenotypic condition of above-ground foliage.
.lant Phenotypic status of above-ground foliage
type Healthy Unhealthy Mean +
--------------------- g/kg -------------------------
- - - - ng/'k - - - -
Q G. O
Leaf 8 20.20 21.50 b
tem 32.20 28.50 30.40 a
a'. -J.. ^ e 11 .10 c
Mea- 1220- 19 93 NS
s Main treatment (plant status) means are significantly dif-
ferent ( -tet) at p=0.05 r not significant, respectively.
3 ubtratmet tissue typ;e means not followed by same
letter are c-. catly different (Duncan'Is NMRT) at p=0.05.
-TM -; ^.rt
- Lr o- -
Table 6. Nutrient concentrations in soils supporting Perlr-
peanut plants displaying foliage character tis:; -
both healthy and unhealthy nutritional u.T.. ..
Mean soil nutrient c:ncentr .t--
Plant ---- --------------------- -----.---- -- ---
status N ? K Ca Mg i.: n
0.359 0C.04 0.013 0. 172 0.025
Unhealthy 0.292 0.025 5 0.009 0. 115 0.018 1.74 .71 0.32
All values are the average of five replications. No significant
differences (F-test) were found between healthy and .ne-althy
plants at p=0.05.
Table 7. Al concentration, organic matter and pH in soil
supporting Perennial peanut plants displaying
foliage characteristics of both healthy and un-
healthy nutritional symptoms.
-- -- -- -- -- -- -- -- -- -- -- ------ -- -- -- -- -- -- -- -- -- -- ---------
Plant Aluminum Organic pH
------------------- ,, ,,,,- I ------- ----- ----------- --. --, -----
--- mg/kg ---
Unhealthy 254.6 1.19 5.56
All values -are the average of five replications. No
significant differences (F-test) were found between
healthy and unhealthy plants at p=0.05.
1" ~" 51. 7
'" HEAL HY
Fig. 1 Tissue N and P.concentrations in terminal leaves
of healthy and unhealthy peanut plants.
F F.OTASSIUM.I CAL.CIUTM AGNESIbUM
Fig. 2 Tissue K, Ca, and ,g concentrations in terminal
leaves of healthy and unhealthy peanut plants.
zc0h PLAN TS
Cu Fe MIn Zn
PLAN T NUIIENT
Fig. 3 Tissue Cu, Fe, Mn, and -n concentrations in terminal
leaves of healthy and unhealthy peanut plants.