Integrated Nutrient Management Strategies for Sorghum and Greengram in Semi-Arid Tropical Alfisol

摘要

A long-term experiment with sorghum (cv CSH-9) and green gram (cv ML-267) as test crops was conducted at Hayathnagar Research Farm of Central Research Institute for Dryland Agriculture, Hyderabad, with the objective to identify effective Integrated Nutrient Management (INM) treatments and to enhance organic matter in dryland soils. The experiment was laid in a strip plot design with two tillage (conventional (CT) and reduced (RT)) and five INM treatments (control, 40 kg N through urea, 4 t compost +20 kg N, 2 t Gliricidia loppings + 20 kg N and 4 t compost + 2 t Gliricidia loppings) Based on the five-year experimental data, it was found that, conventional tillage maintained 14.5 % higher sorghum grain yield compared to reduced tillage. The two INMtreatments, 2 t gliricidia loppings + 20 kg N, and 4 t compost + 20 kg N were found to be most effective in increasing the sorghum grain yield by 84.62 and 77.7 percent over control. In case of green gram, 2 t compost + 11 gliricidia loppings followed by21 compost + 10 kg N were found most promising in increasing the greengram grain yield by 51.6 % and 50.8 % over control respectively. Results clearly indicated that 50 % of N demand of sorghum and green gram could be met through farm-based organic materials like compost or Gliricidia maculata loppings under CT and RT. Among the treatments, highest agronomic efficiency was observed in 2 t gliricidia loppings + 20 kg N (20.32 kg grain kg N~(-1)) followed by 40 kg N through urea (18.61 kg grain kg N~(-1)) in case of sorghum. For green gram, the highest agronomic efficiency was (13.75 kg grain kg~(-1) N) observed in 2 t compost + 1 t Gliricidia loppings treatment followed by 2 t compost +10 kg N (13.56 kg grain kg~(-1) N). Reduced tillage maintained significantly higher organic carbon content (0.74 %) compared to conventional tillage (0.71 %). Highest amount (0.82 %) of organic carbon content was recorded in 4 t compost + 2 t Gliricidia loppings treatment. Other soil parameters such as available N content, DTPA extractable iron and copper contents, and dehydrogenase activity were also significantly influenced by INM treatments studied.