Effect of combined use of organic and inorganic sources of nutrients on sunflower yield, soil fertility, and overall soil quality in rainfed alfisol

To study the response of inorganic and organic nitrogen (N) sources both alone and in conjunction and their influence on soil quality, a field experiment was conducted during kharif and rabi seasons using sunflower (MSFH-8) as test crop. The experimental site soil was Typic Haplustalf situated at Hayatuagar Research Farm of Central Research Institute of Dryland Agriculture, Hyderabad, India, at 17 degrees 18' N latitude, 78 degrees 36' E longitude. The experiment design was a simple randomized block design with 11 treatments replicated four times. Among all the treatments, vermicompost (VC) + Fert at 25 + 25 kg N ha(-1) recorded the highest grain yields of 1878 and 2160 kg ha(-1) during both kharif and rabi seasons, respectively, which were 43.9 and 85.1% higher than their respective control plots. Apparent N recovery varied from as little as 38.30% (FYM at 50 kg N ha(-1)) to 62.16 (25 kg N ha(-1)) during kharif and 49.65 (75 kg ha(-1)) to 83.28% (VC + Fert at 25 + 25 kg N ha(-1)) during rabi season. Conjunctive nutrient treatments proved quite superior to other set of treatments in improving the uptake of N, phosphorus (P), potassium (K), sulfur (S), and inicronutrients in sunflower and their buildup in the soil. Highest relative soil quality indexes (RSQI) were observed under VC + Fert at 25 + 25 kg N ha(-1) (1.00) followed by VC + Gly at 25 + 25 kg N ha(-1) (0.87). Considering the yield and relative soil quality indices (RSQI), conjunctive applications of VC with either inorganic fertilizer, FYM, or Gly at 25 + 25 kg N ha(-1) could be a successful and sustainable soil nutrient management practice in semi-arid tropical Altisols. Besides this, the fertilizer N demand could be reduced up to 50%.