Abstract            Volume:5  Issue-5  Year-2017         Original Research Articles

Online ISSN : 2347 - 3215 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcret@gmail.com

An understanding of the dynamics of soil organic carbon (SOC) as affected by farming practices is imperative for maintaining soil productivity. The objective of this study was to assess the effect of tillage systems and inorganic inputs with K sap on the changes in SOC under rice - wheat rotation in western IGP. Results showed that ZT increased soil bulk density in the 0–20 cm soil layer. Adoption of ZT and PRB increased the concentrations of SOC and TC at 0–15 cm depth but decreased the concentrations in deeper soil. The greatest SOC and TC concentrations were observed under ZT at 0–15 cm depth and under PRB at 15–30 cm depth. Adoption of ZT farming enhanced the SOC and TC stocks in the 0–15 cm layer, whereas PRB increased SOC and TC stocks in the 15–30 cm profile. The stratification ratio (SR) of the SOC and TC concentrations was larger under ZT compared with PRB and CT. Thus, the adoption of short-term (5-6 years) ZT practices is beneficial for the enhancement of SOC and TC stocks in the 0–15 cm soil profile, and rotational tillage may be an appropriate farming practice for rice- wheat system. Application of NPK either through inorganic fertilizers or through combination of inorganic fertilizer and organics such as farm yard manure (FYM) with k sap improved the SOC, particulate organic carbon (POC), microbial biomass carbon (MBC) concentration and their sequestration rate. Application of 75% RDF +25% N through FYM with k sap in rice –wheat rotation sequestered 0.39, 0.50, 0.51 and 0.62 Mg C ha−1yr−1 over control, respectively. SOC with response to application of fertilizer partially substituted (25% on N basis) with organics was higher in 15% k sap. The rice water foot print recorded a significant declining trend in RDF plots where as the water foot print trend was stable at RDF+FYM plots and lower value under unfertilized control. The water productivity in RDF fertilized plots and RDF+FYM with k sap showed either an increasing trend or remained stable at all treatments during six years of the experiment.

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