EFFECT OF NUTRIENT MANAGEMENT ON PHOSPHORUS TRANSFORMATION AND ITS INFLUENCE ON YIELD OF BELL PEPPER (Capsicum annum) UNDER PROTECTED CULTIVATION
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Date
2019-07
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AAU, Jorhat
Abstract
The present investigation entitled "Effect of Nutrient Management on
Phosphorus transformation and its influence on yield of Bell pepper (Capsicum annum)
under protected cultivation was carried out in the Horticulture Farm of AAU, Jorhat-
13. The experiment was conducted maintaining Split-split design having three(3)
factors(Nitrogen, Phosphorus and Potassium) and each having three (3) levels(N-
80,100,120 P-40,60,80 K-40,60,80) accounting for a total treatment combination of
twenty seven (27) having replicated thrice(3). Small portion of soils was collected from
different treatments under protected cultivation at a depth of 0-15 cm. The soil samples
were collected at two different stages of the crop viz., flowering and fruiting stages i.e
45 and 115 DAP respectively and was analyzed for different physico-chemical properties.
The initial study revealed that the texture was silty loam with a bulk density of 1.176g
cm-3 and the particle density 1.18 Mg m-3. Organic C (%) was found in the high range
(0.94%) with a CEC of 13.7 cmol(p+) kg-1 of soil. The soil was acidic with a pH value of
5.32. Soil was having initial NPK content i.e 535.66 kg ha-1, 36.25 kg ha-1 and 68.56 kg
ha-1 respectively.
The present study revealed that the single factor effect of treatment has a
significant effect on soil chemical properties, plant nutrient partitioning and various
forms of P, except for Residual P which was found to be non-significant. The
interaction effect of NP found to be significant with the physico-chemical parameters
.The NP interaction with plant nutrient partitioning found that the highest values
(3.383%,1.365%N and 0.385,0.366%P) of leaf and shoot nitrogen and phosphorus
content are obtained in the higher dose of nutrients(N120P80) and highest value in leaf
and shoot K(4.996% and 4.126%) are found in low to medium dose of fertilizer in the
flowering stage but in the fruiting stage, higher values are obtained in the medium dose
of NP levels . NP interaction with different forms of P is also found to be significant
and the highest values are obtained in medium to high dose of fertilizer (N-100,120 and
P-60,80). Available P and exchangeable Ca and Mg were found to be high in the low
level of NK interaction. The leaf and shoot N and K content tends to increase with the
increase level of NK fertilizers. Various forms of P were found to be high in the low to
medium level of NK interaction (N-80,100 and K-40,60). For PK interaction, Available
N was found to be highest (766.5 kg ha-1) in the low to medium dose of PK and
available P2O5 & K2O were found to be high in higher level of treatments (P80K80). CEC
was found to be non-significant in the flowering stage but found to be significant in the
Fruiting stage. Similar results were found as in NK interaction with the plant nutrient
partitioning i.e high NPK leaf and shoot content were found in the medium to high level
of PK. Different forms of P were also found to be significant with the PK interaction
and the highest values were observed with the higher dose of P. In the Interaction effect
of NPK, all the physico-chemical properties are found to be significant. The plant
nutrient partitioning and the various forms of P, except for Residual P were also found
to be significant with the interaction effect of NPK. The present study suggested that the
nutrient management was found to influence the physico-chemical properties of the soil
as well as various forms of P, except for Residual-P. The different forms of P were
found to poorly explain the yield variability and did not influence yield directly. This
implies that time may be a limiting factor for conversion of applied phosphorus to
different P fractions. Different soil P fractions may influence the yield indirectly
through other soil factors as founded by use of appropriate statistical tools. Furthermore,
only N was found to be playing a dominant role in predicting the yield of capsicum
under protected cultivation. The time of application of N also plays a vital role for the
increased production of capsicum. The application of N just before fruiting stage gave
better result compared to other critical growth stages during the study period. The best
treatment combinations for higher yield of capsicum were when medium to high dose of
N (N-100, 120) and P (P-60, 80) and low to medium dose of K (K-40, 60) was applied.
Further studies may be conducted at different physio-geographical locations to get a
robust nutrient recommendation for capsicum under protected cultivation.