Long-term effect of integrated nutrient management on crop yield and phosphorus and potassium fractions in rice-wheat rotation
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Date
2012
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Publisher
CCSHAU
Abstract
An ongoing long-term experiment under rice-wheat cropping was selected to investigate the effect of
organic and inorganic fertilization on crop productivity, and on amounts and distribution phosphorus and
potassium fractions in soil. Balanced application of nutrients (N150P75K75Zn25) increased the grain yield of rice
significantly as compared to control or imbalanced application of nutrients to rice crop. Application of FYM along
with inorganic fertilizers increased the rice grain yield by 4.9 q ha-1 over that obtained with mineral fertilizer only
treatment (N150P75K75Zn25). The grain yield of rice was significantly higher in FYM amended treatment as
compared to any other organic manure amended treatment. Rice grain yield did not differ significantly among
press mud, green manure, burnt rice husk and mineral fertilizer only treatments (N150P75K75Zn25) treatments.
Application of N75P37.5K37.5Zn25 in green manured plot produced rice grain yield similar to that obtained with
N150P75K75Zn25 treatment indicating a saving of approximately 50% of inorganic fertilizers in rice with Sesbania
green manuring.
The residual effect of organic amendments on grain yield of succeeding wheat was significant and the
highest residual effect in terms of wheat grain yield was observed in case of FYM amended treatment. Application
of inorganic fertilizers along with organic manures significantly increased the uptake of macro- and micronutrients
by rice and wheat crops as compared to inorganic fertilizer alone treatment.
Fifteen years of continuous cropping without any P fertilization decreased the contents of saloid-P, Al-P,
Fe-P, Ca-P and RS-P over their initial status in soil. However, the significant decrease was observed only in case
of Al-P, Fe-P and RS-P. On the contrary, application of phosphorus in combination with N150 or N150K75 or
N150K75 Zn25 increased saloid-P, Al-P, Fe-P, Ca-P and RS-P significantly over control.
The Al-P increased by 9.7, 31.4 and 9.0%; Fe-P by 21.0, 21.7 and 14.8%, and RS-P by 17.8, 21.2 and
15.8% with the application of inorganic fertilizers in combination with FYM, press mud, burnt rice husk,
respectively over mineral fertilizer treatment (N150P75K75Zn25). The increase in Ca-P was 14.0, 22.5 and 12.4% in
the corresponding treatments over mineral fertilizer only treatment. The total P contents were higher by 19.5% and
24.9% in FYM and press mud amended treatments, respectively compared with N150P37.5K37.5Zn25 + green manure
treatment.
The water soluble, exchangeable and non exchangeable K decreased significantly over their initial status
after 15 cycles of rice-wheat cropping in control treatment. The amount of total K decreased significantly over its
initial status after 15 years of continuous rice-wheat cultivation and none of the treatments either inorganic
fertilizer treatment or inorganic plus organic manure amended treatment were able to maintain K levels close to
initial status.
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Keywords
Organic fertilizers, Crops, Rice, Fertilizers, Farmyard manure, Wheats, Diseases, Yields, Green manures, Crop residues