Vol. 7, Issue 6 (2019)

Among the various tillage practices, the low tillage (LT) practice significantly improved labile carbon fractions viz. WSC, POSC, and POMC over the period of nine years at all three soil depths as compared to medium tillage (MT) and conventional tillage (CT) with the exception of POSC at a depth of 30-45 cm, where tillage effects were non-significant. Whereas, the tillage effects were non-significant for SMBC at all three soil depths Similarly, among nutrient management practices, the exclusive organic treatment (N1) wherein the total nitrogen requirement of (50 kg N ha^-1) rainfed rabi sorghum was met through crop residues (byre waste) plus green leucaena loppings, significantly improved WSC, POSC, POMC, at all three soil depths as compared to INM treatment (N2) and exclusive chemical fertilizer treatment N3. The SMBC was significantly increased due to N2 as compared to N1 and N3 treatments.

The interaction between low tillage and nutrient management through organics (LT N1) was the best interaction for WSC, POSC, and POMC at all three depths of soil.

In general, the concentration of all carbon fractions was higher at the surface soil layer and gradually decreased with increase in soil depth. The lowest values of WSC, POSC, POMC, SMBC, were observed in control treatment at all the three soil depths.