SOIL QUALITY INDEXING OF AN ACID ALFISOL UNDER RICE-WHEAT CROPPING SYSTEM BASED ON CONTINUOUS INTEGRATED PLANT NUTRIENT SUPPLY IN MID-HILLS OF HIMACHAL PRADESH
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Date
2019-01-07
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CSKHPKV. Palampur
Abstract
Present investigation was carried out in a long-term integrated nutrient management
experiment with rice–wheat cropping sequence initiated in kharif 1991 at Padhiyarkhar research
farm of College of Agriculture, Palampur, District Kangra. Twelve treatments comprising of T1-
Control (no fertilizer, no manure), T2-50% NPK to both rice and wheat, T3-50% NPK to rice and
100% NPK to wheat, T4-75% NPK to both rice and wheat,T5-100% NPK to both rice and wheat,
T6-50% NPK + 50% N through FYM to rice and 100% NPK to wheat, T7-75% NPK + 25% N
(FYM) to rice and 75% NPK to wheat, T8-50% NPK + 50% N through wheat straw to rice and
100% NPK to wheat, T9-75% NPK + 25% N (wheat straw) to rice and 75% NPK to wheat, T10-
50% NPK + 50% N through Dhaincha green manure to rice and 100% NPK to wheat, T11-75%
NPK + 25% N (Dhaincha green manure) to rice and 75% NPK to wheat and T12-Farmers‟
Practice (40% NPK + FYM @ 5 t ha-1
to both the crops) were evaluated in a randomized block
design with four replications. Surface (0–0.15 m) and sub-surface (0.15–0.30 m) soil samples
were collected after the harvest of wheat crop during 2016-17 and analyzed for various soil
physical, chemical and biological properties. Integrated use of organics and inorganics has
sustained the crop productivity and significantly improved the soil properties. Sustainable yield
index (SYI) was found lowest (0.33) in the treatment where no fertilizer or manure was applied
(T1) and highest (0.66) where 50 per cent NPK through fertilizers and 50 per cent N through FYM
to rice was followed by 100 per cent NPK to wheat (T6). Available nitrogen and potassium
declined over the years in all the treatments whereas significant build-up in available phosphorus
was observed through integrated use of organics and fertilizers over the respective initial values.
Saturated hydraulic conductivity, pH, organic carbon, labile carbon, microbial biomass nitrogen
and dehydrogenase activity were found to be the key minimum data set (MDS) indicators in this
study. Multiple regression evaluated the efficacy of MDS taking SYI as goal (r2
=0.91 for surface
and 0.88 for sub-surface soil). The soil quality index (SQI) was calculated by using weighting
factors derived from principal component analysis for each scored MDS variable. The highest SQI
values (2.81 for surface and 2.78 for sub-surface soil) were found in T6 followed by T10 (2.41 for
surface and 2.56 for sub-surface soil) and the lowest (1.16 for surface and 1.23 for sub-surface
soil) in T1. Application of 50% NPK through chemical fertilizers + 50% N through FYM in rice
followed by 100% NPK in wheat (T6) was found to be better than other treatments in sustaining
crop productivity as well as maintaining soil quality under rice-wheat cropping sequence.