Production potential, nutrient-use efficiency and economics of groundnut (Arachis hypogaea)–onion (Allium cepa) cropping system under organic nutrient management

A field experiment was conducted during 2010–11 and 2011–12 at Bengaluru, Karnataka to study the effect of organic nutrient management practices on the production potential, nitrogen-use efficiency and economics of groundnut (Arachis hypogaea L.)–onion (Allium cepa L.) cropping system. Application of enriched biodigested liquid organic manure (EBDLM) at 25 kg N equivalent/ha + 3 sprays of panchagavya (PG) at 3% resulted in significantly higher pod and kernel yields and total system productivity (2.34, 1.78, 10.1 and 12.4 t/ha, respectively) and yield attributes like number of pods/plant and shelling outturn (47.2 and 76.0% respectively) of groundnut. The bulb yield of onion (37.78 t/ha) and yield parameters, viz. bulb diameter (6.10 cm), bulb length (5.52 cm), bulb size index (33.7), scale leaves/bulb (11.60), fresh weight (110.1 g) and specific gravity of bulb (1.41 g/cc), were significantly higher with EBDLM at 125 kg N equivalent/ha + 3 sprays of PG at 3%. Significantly higher total uptake of N, P and K (183.7, 66.0 and 117.2 kg/ha respectively) by groundnut and onion was recorded with EBDLM at 25 (groundnut)/125 (onion) kg N equivalent/ha + 3 sprays of PG at 3% and nitrogen-use efficiency in groundnut (29.6 kg/ha) and in onion (131.6 kg/ha) was also higher with EBDLM at 25 (groundnut)/125 (onion) kg N equivalent/ha + 3 sprays of PG at 3%. At the end of 2 cropping cycles, application EBDLM at 25 (groundnut)/125 (onion) kg N equivalent/ha + 3 sprays of PG at 3% resulted in higher balance of N, P and K than recommended practice. Net returns (426.6 × 10³/ha) and benefit: cost ratio (4.13) were more with EBDLM at 25 (groundnut)/125 (onion) kg N equivalent/ha + 3 sprays of PG at 3%.