Nitrate distribution in soil profile and yield of cotton in relation to different levels of nitrogen
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Date
2007
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Publisher
CCSHAU
Abstract
The present investigation was undertaken to study the
nitrate distribution in soil profile and yield of cotton in relation to
different levels of nitrogen. To achieve the objectives, a field experiment
was conducted in micro plots (2M×2M) at the research farm of CCSHAU,
Hisar. Cotton crop was taken with seven treatments of nitrogen viz., 0,
34.50, 45.54, 34.50, 40.02, 34.50 and 11.04 g N per plot applied through
urea and/or nitrate containing irrigation water. The experimental results
showed that mean EC, Ca2+, Mg2+, Na+, K+, HCO3-, Cl-, SO42-
concentration of the soil profile decreased after the harvest of the crop as
compared to at the start of the experiment irrespective of treatments. The
maximum NO3–N, 47.88 (Kg/ha) was observed in T3 treatment
after first irrigation in 0-15 cm soil depth while the minimum NO3–N,
5.39 (Kg/ha) in T1 treatment in 30-45 cm depth after first irrigation. The
depth distribution of NO3–N concentration of the soil profile was
predicted using models i) LEACHM considering water flow equation of
Addiscot, uptake, transformation of different forms of nitrogen, rate
constants, other exchange processes and weather parameters and ii) Pal
et al. 1990, considering initial NO3–N concentration of the soil profile and
of the irrigation water, evaporation/ evapo-transpiration, rainfall and
field capacity of the soil profile. The magnitude and the trend of the
experimental and the simulated NO3 concentration of the soil profile
after different irrigations and harvest of the crop showed a good
agreement between the two by LEACHM model (r2= 0.92, a= -3.18 and
b= 1.51) where as by the Pal et al. 1990 model, the agreement was not up
to the mark. (r2= 0.45, a= 3.67 and b= 0.448). Crop removal of nitrogen was highest in T7 treatment (93.5 Kg
N/ha) and lowest in T1 treatment (91.7 Kg N/ha), respectively. At
sowing, the total nitrogen in the soil profile was 186.8 Kg N/ha (157 Kg
NO3 /ha and 29.8 Kg NH4/ha) while at the time of harvest, the total nitrogen was highest in T3 (132.1 Kg N/ha) and lowest in T1 (64.6 Kg
N/ha).
The mean plant height value was found to be lowest (138.50
cm) under T1 and highest (167 cm) in T3 treatment. The highest mean
number of bolls was observed in treatment T3 (33.50) and lowest
treatment T1 (16). The highest and the lowest mean cotton yield of
389.50 and 225.75 gm/plot were obtained under treatments T3 and T1,
respectively.
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Keywords
Irrigation, Inorganic acid salts, Nitrogen, Crops, Cotton, Yields, Organic compounds, Leaching, Marketing, Fertilizers