Organic manures and nutrient solubilizers for organic cultivation of summer groundnut (Arachis hypogaea) in black calcareous soil

A field experiment was conducted during summer 2015 at Junagadh, Gujarat, to evaluate different nutrient sources and nutrient solubilizers for production of organic groundnut (Arachis hypogaea L.) in black calcareous soil. Results revealed that, though recommended dose of fertilizers (RDF) resulted in significantly higher growth and yield attributes, and yield of summer groundnut, but higher net returns were achieved with application of FYM @ 5 t/ha owing to premium price. Similarly, higher available P and K after harvesting was recorded with RDF but the maximum available soil N, S, DTPA-extracted Fe, Mn, Zn, and B, soil enzymatic activities (dehydrogenase, acid and alkaline phosphatase) at 90 days after sowing (DAS) were found with FYM @ 5 t/ha. Significantly maximum growth and yield attributes, pod yield, available nutrient in soil (N, P, K and S), and soil enzymatic activities at 90 DAS were observed with all-nutrient solubilizers @ 2.5 L/ha. However, significantly maximum DTPA-extracted Fe, Mn, Zn, and B were recorded with micronutrient solubilizers @ 2.5 L/ha.