Effect of Micronutrients Rate, Method and Time of Application on Yield and Quality of Fingermillet-Groundnut Cropping System Under Alfisols of Karnataka.

Under dryland conditions in Alfisols of Karnataka, India due to uneven distribution of rainfall coupled with poor management of nutrients and intensive cropping system results in lower yields. Improvement in yield is likely to occur in smaller increments through efficient crop and nutrient management. We hypothesized that under fingermillet (Eleusine coracana Gaetrn.)–Fallow–groundnut (Arachis hypogaea L.) cropping system yield and nutrient use efficiency could be increased by application of micronutrients (boron and zinc) and bioinoculants (phosphorus solubalizing bacteria, vasicular arbiscular mycoriza, and rhizobium). On-station and on-farm studies were conducted during 2004, 2005, and 2006 at Dryland Research Center, Bangalore and across the dryland farm sites of Karnataka. Soil analysis at experimental sites before sowing showed low nitrogen, medium phosphorous and potassium content and soils were deficient in zinc (69%) and boron (26%). Results revealed that under finger millet-fallow-groundnut cropping system, soil application of boron (2 kg ha^-1) and zinc (2.5 kg ha^-1) enhanced dry matter, yield and yield components, nutrient uptake, and micronutrient use efficiency. Foliar spray of boron (0.25 % weight/volume) and zinc (0.53 % weight/volume) during flowering period was equally effective. The yield response to applied micronutrients (in addition to normal levels of NPK) was up to 13.4 to 20 % in fingermillet, 25-30 % in groundnut compared to the soils with only NPK. Further, micronutrients use efficiency was enhanced when applied in combination with bioinoculants. Soil toxicity can be reduced by application of zinc and boron during alternate-crop-years. Cost benefit ratio was also higher with soil and foliar application of boron and zinc. Our results suggest that combined application of major and micronutrient along with bio-inoculants will increase grain yield, yield parameters, soil fertility, and nutrient uptake (8-10%) apart from improving seed viability and seed vigour.