Effect of phosphorus and farmyard manure applied to sunnhemp, (Crotalaria juncea) on yield and nutrient uptake of sunnhemp-wheat (Trticum aestivum) cropping system and fertility status in a Typic Ustocrept of Uttar Pradesh

Abstract

A field experiment with sunnhemp (Crotalaria juncea L.) -wheat (Triticum aestivum L. emend. Fiori & Paol.) cropping system was conducted during 2004 and 2005 to study the effect of phosphorus and farmyard manure levels on yield and nutrient uptake of sunnhemp and their residual effect on wheat and changes in soil fertility status. Application of farmyard manure @ 5 tonnes/ha recorded an increase of 13.9% in fibre yield over the no farmyard manure. Fertilizer phosphorus significantly increased the fibre yield of sunnhemp by 14.69% over the no phosphorus at 40 kg P2O5/ha. The highest fibre yield (0.90 tonne/ha) was recorded with combined application of 60 kg P 2O5 and 7.5 tonnes farmyard manure/ ha which was 45.2% higher than the yield of without phosphorus and farmyard manure. The total nitrogen, phosphorus and potassium uptake by sunnhemp increased significantly with applied phosphorus up to the maximum level of 60 kg P2O 5/ha but the favourable effect with farmyard manure was recorded up to 5 tonnes/ha only. The increase in nitrogen, phosphorus and potassium uptake with 60 kg P2O5/ha were 20.5, 44.0 and 54.9% respectively over no phosphorus. Grain and straw yield of wheat increased significantly with farmyard manure at 5 and 7.5 tonnes/ha applied in sunnhemp over no farmyard manure although the yield recorded with 5 and 7.5 tonnes farmyard manure/ ha were at par. The increase in grain and straw yield under 5 tonnes farmyard manure/ha was 6.60 and 14.05% respectively. Combined dose of 60 kg P 2O5 with 7.5 tonnes farmyard manure/ha applied in sunnhemp recorded highest grain yield of wheat (4.55 tonnes/ha) which was 21.3% higher than that of without phosphorus and farmyard manure. The nitrogen, phosphorus and potassium uptake by wheat crop increased significantly due to the residual effect of farmyard manure and phosphorus applied in sunnhemp crop. Application of phosphorus and farmyard manure had significantly improved the organic carbon and available nitrogen, phosphorus and potassium status in post-harvest soil after 2 years of cropping.