The organic manures and biochar amendment plays a pivotal role in organic production system. A study was conducted to evaluate the effect of organic sources of nutrients and low-cost biochar technology on maize and black gram yield along with mineral nutrients acquisition pattern under fully organic production system. The results of this study revealed that the maize grain yield (t ha(-1)) was maximum in poultry manure 5 t ha(-1) + biochar 5 t ha(-1) – T-7 (4.63) and minimum in FYM @ 10 t ha(-1) + biochar 0 t ha(-1) – T-2 (4.04) compared to control (2.67). Similarly, the net return (x 10(3) Rs. ha(-1)) and B:C ratio in maize was maximum in T-7 (50.12 and 1.77) and minimum in T-2 (37.45 and 1.53) compared to control (12.11 and 0.76). The black gram grain yield (kg ha(-1)) was maximum in T-7 (1094) and minimum in T-2 (952) compared to control (406). The net return (x 10(3) Rs. ha(-1)) and B:C ratio of black gram was maximum in T-7 (42.86 and 3.12) and minimum in T-2 (32.19 and 2.71) compared to control (13.30 and 1.48). The maize grain N content and uptake was maximum in T-7 (2.52 and 91.38) and minimum in FYM @ 10 t ha(-1) + biochar 2.5 t ha(-1) – T-3 (2.36 and 69.26) than control. The black gram grain N content and uptake was maximum in T-7 (3.19 and 98.63) and minimum in T-3 (3.03 and 78.51) than control. Similarly, maize stover grain N content and uptake was maximum in T-7 (0.51 and 61.16) and minimum in T-3 (0.40 and 45.74) than control. The black gram grain N content and uptake was maximum in T-7 (0.63 and 67.76) and minimum in T-3 (0.52 and 52.34) than control. Finally, it can be recommended that maize grain yield (t ha(-1)) was maximum in poultry manure 5.0 t ha(-1) + biochar 5.0 t ha(-1) (4.63) and in black gram the grain yield (kg ha(-1)) was also maximum in poultry manure 5.0 t ha(-1) + biochar 5.0 t ha(-1) (1094). Thus, this treatment can be recommended under Sikkim mid hill ecosystem of India for increasing the production and productivity in maize-black gram cropping system to restore soil productivity.
