Long-term effect of nutrient management and rainfall on pod yield of groundnut (Arachis hypogaea) in groundnutbased cropping systems

A field experiment was conducted from 1999 to 2008 on fixed site at the research farm of Directorate of Groundnut Research, Junagadh (Gujarat) to develop a sustainable nutrient management schedule for groundnut ( Arachis hypogaea L.)based cropping systems, and to find out the influence of seasonal rainfall on pod yield of groundnut. Combination of 14 treatments of inorganic nutrients (100% RDF and 50% RDF) and farmyard manure (5 t/ha) were applied to groundnut and the component crops of groundnut-wheat and groundnut-wheat [ Triticum aestivum (L.) emend. Fiori & Paol]-greengram [ Vigna radiata (L.) Wilczek] cropping systems. Integrated use of or- ganic and inorganic nutrients (FYM 5 t/ha+50% RDF) to kharif groundnut recorded significantly higher pod yield (1,037 kg/ha) and the total system productivity in terms of groundnut equivalent yield (2,187 kg/ha) over the use of inorganic nutrients. This combination also recorded higher sustainable yield index and predictability over the use of inorganic nutrients across the experimental period. Among cropping systems, the total system productivity was significantly higher in groundnut-wheat-green gram cropping systems 2.34 + GPEY/ha with the integrated use of organic and inorganic nutrients. The rainfall in June had a significant effect on pod yield of groundnut when sup- plied with both organic and inorganic nutrients (FYM 5 t/ha+50% RDF). Depending upon the amount and period, rainfall received in the months of June and July had a positive effect on pod yield of groundnut, however, August and September rainfall showed negative effect.