Impact of 12-year-long rice based organic farming on soil quality in terms of soil physical properties, available micronutrients and rice yield in a typic Ustochrept soil of India

Long-term use of chemical fertilizers has been known to degrade the various soil physico-chemical properties. Incorporation of crop residues (CR) along with biofertilizers (BF) is an important practice from improving the physico-chemical properties of soil. Laboratory analyses were conducted during 2015 on soil samples collected from an on-going long-term experiment "Nutrient management in rice based organic farming systems," in progress since 2003. Over the 12 years of study a significant improvement in bulk density, water-holding capacity, aggregate stability, hydraulic conductivity, and soil pH was observed under conjoint application of organics, CR, and BF in farmyard manure (FYM)+CR+BF and VC+CR+BF treatments. The data further delineated maximum soil organic carbon build-up was recorded in the combined application of organic nutrient sources as compared to manures alone treatment. The data further indicated that DTPA extractable copper, zinc, manganese, and iron in soil recorded a significant increase in all the manures applied treatments under rice-wheat-mungbean and rice-wheat cropping systems over the initial level. The integrated use of organics and crop residues in combination with biofertilizers recorded significant higher rice grain and straw yields over the rest of the treatments. Organic manures in combination with crop residues and biofertilizers supported high rice grain yield and straw biomass and sustainable yield index (SYI), with lower values of coefficient of variance. In conclusion, the conjoint application of organics, crop residues, and biofertilizers can enhance not only rice crop yield but also yield stability and sustainability.