Productivity, profitability and sustainability of integrated nutrient management practices in yam (Dioscorea esculenta) + maize (Zea mays) intercropping system

Field experiments were conducted at Phulbani, Orissa for 5 years during 2002–03 to 2006–07 to find out appropriate integrated nutrient management practice for yam + maize (1:2) intercropping system under rainfed condition to achieve higher system productivity, profitability and sustainability. Yam (100% population) and maize (45% population) received nutrient dose of 80 kg N + 26.2 kg P + 66.7 kg K and 36 kg N + 7.9 kg P + 15 kg K ha⁻¹, respectively. Nutrient sources included various proportions of chemical fertilizer (CF), FYM or green leaf (GL). Integrated nutrient management practices influenced yield of both yam and maize significantly during all the years. Over seasons, integration of 50% chemical fertilizer with 50% N as FYM proved significantly better than all other nutrient management practices and registered maize green cob yield of 3.81 t ha⁻¹, yam tuber yield of 8.81 tha⁻¹ and yam tuber equivalent yield of 10.97 tha⁻¹ and benefit: cost ratio of 1.30. This was followed by 50% chemical fertilizer+50% N as greenleaf with maize green cob yield of 3.45 t ha⁻¹, yam tuber yield of 8.35 t ha⁻¹, yam tuber equivalent yield of 10.27 t ha⁻¹ and benefit: cost ratio of 1.21. Both the INM practices were equally and highly sustainable with SI value of 0.57. After five years of experimentation, INM practices and Farmers Practice of FYM only recorded higher organic carbon content and available P in soil as compared to application of chemical fertilizer only. Application 50% chemical fertilizer (40 kg N+13.1kg P + 33.3 kg K and 18kg N+3.9kg P + 7.5kg K ha⁻¹ for yam and maize, respectively) coupled with 50% N as FYM (11.6 t ha⁻¹) or greenleaf (Glyricidia leaves @ 14.5 t ha⁻¹) may be recommended for sustained higher productivity and profitability of yam + maize (1:2) intercropping system under rainfed conditions.