Productivity, nutrient uptake and economics of groundnut (Arachis hypogaea)- toria (Brassica rapa subsp. dichatoma) cropping system as influenced by direct and residual effects of micronutrient and liming

A field experiment was conducted at the ICAR Research complex for NEH Region, Umiam, Meghalaya, during the rainy (kharif) and winter (rabi) seasons of 2013, to assess the direct and residual effect of micronutrients and liming on productivity, nutrient uptake and economics of groundnut (Arachis hypogaea L.)-toria [(Brassica rapa subsp. dichotoma (Roxb.) Hanelt)] cropping system. The experiment was laid out in a factorial randomized block design with 6 micronutrients (soil application) treatments, viz. control (no micronutrient), Zn @ 5 kg/ha, B @ 1 kg/ha, Mo @ 0.5 kg/ha, Zn + Mo, Zn + B + Mo, and 2 levels of lime, viz. lime @ 500 kg/ha (application in furrow) and no lime. Sole application of Mo produced significantly higher yield of groundnut (1.72 t/ha) compared to control (1.32 t/ha) and was at par with Zn + Mo (1.78 t/ha) and Zn + B + Mo (1.8 t/ha). The maximum yield of succeeding toria was recorded with the residual effect of Zn + B + Mo (0.53 t/ha) which remained at par with residual effect of B (0.52 t/ha). Direct and residual effects of liming increased the yield of groundnut and of succeeding toria by 13.3% and 21.9%, respectively, over no liming. Integrated application of Zn + Mo and Zn +B + Mo recorded significantly highest N, P and K uptake of groundnut, whereas, residual effect of combined application of Zn + B + Mo recorded the highest N, P and K uptake of succeeding toria. Direct effect of Mo in groundnut and residual effect of B in toria was more pronounced in enhancing productivity and nutrient uptake than other sole micro nutrient application. Direct and residual effect of Zn +B + Mo resulted in the highest groundnut-equivalent yield (2.18 t/ha) and net returns (52.8/ha) of the system which was at par with Zn + Mo (2.11 t/ha and 49.8/ha, respectively).