Micro-nutrient management for soil fertility, nutrients uptake and productivity of greengram (Vigna radiata) and finger millet (Eleusine coracana) under semi-arid Alfisols

摘要

Three field experiments of greengram [Vigna radiata (L.) Wilczek] followed by finger millet [Eleusine coracana (L.) Gaertn.] in sequence with 12 treatments of micro-nutrients in combination with recommended NPK fertilizers applied to finger millet were conducted during 2005-2007 in a semi-arid Alfisols at Bengaluru, Karnataka. The effects of treatments on available soil and plant uptake of nutrients and yield of crops were assessed. Using the relationships of yield with soil and plant nutrient variables, regression models of yield through soil and plant variables were calibrated and effects of variables on crop yields were assessed. The models gave high and significant yield predictability in the range of 0.92-0.98 through different variables. The model of plant uptake through soil nutrients indicated that soil sulphur, iron and zinc had a significant positive effect; while soil N, K, boron and molybdenum had a negative effect on plant nutrient status in greengram. Similarly, soil P, manganese andzinc had a significant positive effect, while soil N, K and iron had a negative effect on plant uptake of nutrients in finger millet. Based on a relative efficiency index (REI) criterion, recommended NPK + ZnSO_4 @ 12.5 kg/ha + borax @ 10 kg/ha + Mo @ 2g/kg seed (9.68) was superior for maximum plant uptake, while recommended NPK + FYM @ 10 t/ha (9.21) was superior for maximum soil fertility of nutrients in greengram. In finger millet, recommended NPK + FYM @ 10 t/ha (8.70) showed the maximum REI for soil nutrients, while recommended NPK + ZnSO_4 @ 12.5 kg/ha + borax @ 10 kg/ha (9.71) the maximum REI for plant uptake of nutrients. The combined REI over soil and plant nutrients for both crops indicated that application of NPK + ZnSO_4 @ 12.5 kg/ha + borax @ 10 kg/ha + Mo @ 2 g/kg seed could be prescribed for attaining maximum plant uptake of nutrients and productivity of greengram and finger millet in sequence, apart from maintaining maximum soil fertility of nutrients under semi-arid Alfisols.