Short term effects of conservation agriculture practices on soil quality under rice wheat cropping system

Abstract

newline Intensive tillage, removal or burning of crop residues, limited organic manure use, declining irrigation water resources are the major causes of soil degradation and unsustainability of rice (Oryza sativa L.)-wheat (Triticum aestivum L.) system (RWS) in South Asia. Present investigation on Short-term effects of conservation agriculture practices on soil quality under rice-wheat cropping system was carried out at research farm, Chatha, SKAUST-Jammu. The objectives of the study were to evaluate the effect of CA on yield and soil quality with special reference to the carbon dynamics in soil. The experiment was established in 2015 in a factorial RBD plot design with three replications. The two factors under this experiment were conservation agriculture (CA) and weed management practices (WM). Under the CA, five levels were conventional agriculture (CTR-CTW), partial CA1 (CTR-ZTW-ZTG), partial CA2 (CTDSR-CTW-ZTG), full CA1 (ZTDSR-ZTW+R-ZTG) and full CA2 (ZTDSR+R-ZTW+R+ZTG). The three levels for weed management were chemical herbicide, integrated weed management and weedy check. The results showed that full CA2 treatment resulted in reduced subsurface compaction, increased hydraulic properties (saturated hydraulic conductivity and infiltration ) and improved soil aggregation ( MWD and GMD) as compared to conventional agriculture. Available nitrogen, phosphorus, potassium and DTPA-Zn in surface soil layer under full CA 2 were significantly higher by 13.5, 51.2, 55.6 and 14.4 per cent, respectively over that under conventional agriculture treatment at the end of four year of continuous crop cycles whereas, lower values DTPA-Zn and Mn were reported under CA treatments as compared to those in conventional agriculture. The biological indicators i.e. dehydrogenase, alkaline phosphatase, MBN and bacterial and fungal count under full CA2 were significantly higher by 104.3, 40.6, 32.1, 31.3 and 31.9 per cent, respectively over that under conventional agriculture treatment. As compared to conventional agricult