Soil properties and soybean yield as influenced by long term fertilizer and organic manure application in a vertisol under soybean-wheat cropping sequence

Long term fertilizer experiment was initiated during 1972 under All India Coordinated Research Project with soybean -wheat cropping system at the Research Farm of Department of Soil Science, JNKVV, Jabalpur, Madhya Pradesh, India. The present study was taken during 2017 and 2018 in soybean crop.

The present investigation was conducted with eight treatments i.e. 50% NPK, 100% NPK, 150% NPK, 100% N alone, 100% NP, 100% NPK + farmyard manure (FYM) @ 5 t ha^-1 yr^-1, 100% NPK (-S) and unfertilized plot (control), replicated four times in a randomized block design.

A significant increase in soil organic carbon was recorded with 100% NPK + FYM @ 5 t ha^-1 over control plot. The availability of N, P, K, S, soil microbial biomass carbon (SMBC) and soil (SMBN) increased significantly with the integrated application of fertilizers and FYM over imbalance application fertilizer or control. Further, the conjoint use of fertilizers and FYM was also significantly superior to other treatments in terms of activities of soil enzymes like dehydrogenase, acid phosphatase, alkaline phosphatase and β-glucosidase.