Biochar and Biofertilizers Residual Effect on Fertility Status of Soil Two Crop Seasons after their Application

Biochar application is one of the highly discussed mechanisms to enhance soil fertility worldwide. Manipulation of this amendment to enhance its role in soil fertility management is a new area of research. In this study, it was applied to soil in three particle sizes ( 2, 2-5 and 5-10 mm) in combination with two commercial biofertilizers; Bizote-N and Rhizogold to lentils during Winter 2015 in an RCB design and the residual effect was evaluated on soil micro-nutrient status and chemical properties after maize harvest in Summer 2016. Particle sizes in the above order showed 3, 2 and 2% increase in soil pH over the control (7.63) and 15, 10 and 6% increase in soil EC over the control (125 mS cm^-1), respectively. Their OM contents (1.73, 1.68 and 1.67%) registered 98, 93 and 91% increase over the OM in the control (0.87%), respectively. Amonium bicarbonate diethylene triamine penta acetic acid (AB-DTPA) extractable soil Fe after 2, 2-5, 5-10 mm particles size treatments and the control was 2.48, 2.06, 1.99 and 1.81 mg kg-1, Zn was 0.41, 0.36, 0.33 and 0.31 mg kg^-1, Mn was 1.23, 1.05, 1.02 and 0.89 mg kg^-1, and Cu was 0.51, 0.38, 0.37 and 0.26 mg kg-1, respectively. Bizote-N and Rhizogold treatments OM (1.5 and 1.48%) showed 3 and 0.7% increase over the control (1.47%), respectively,. Bizote-N induced increase in Fe, Zn, Mn and Cu (2.16, 0.61, 1.23 and 0.45 mg kg^-1) were significantly higher by 7, 238, 45 and 55% while their content in Rhizogold treatment (2.07, 0.24, 1.05 and 0.40 mg kg-1) showed a significant increase (by 33, 24 and 38%) only in Zn, Mn and Cu over the control (2.02, 0.18, 0.85 and 0.29 mg kg^-1, respectively ) In interaction, Bizote-N was significantly higher in OM content at the 2 mm biochar particles size, increased soil micronutrients fertility and soil properties over the Rhizogold and the biofertilizer control. It was concluded that Bizote-N in combination with reduced particle size of biochar had significantly higher residual effect on soil fertility improvement that can be used for higher crop production in legume-cereal cropping pattern.