Influence of litter fall of jatropha (Jatropha curcas) and castor (Ricinus communis) on nitrification inhibition and microbial parameters under sandy loam soil in sunflower (Helianthus annuus)

Abstract

A pot experiment was conducted at IARI, ew Delhi during the spring season of 2007 and 2008 on sandy loam soil to evaluate the influence of litter fall of castor and jatropha for its nitrification inhibition and microbial properties in sunflower (Helianthus annuus L. ). The results revealed that application of 100% RDF (80, 26. 2 and 33. 3 kg NPK/ha) has the highest plant height, leaf area index (LAI), seed yield (8. 92 and 9. 25 g/plant in 2007 and 2008), biological yield (27 and 25 g/plant in 2007 and 2008) and harvest index, statistically on par with 75% RDF + 25% RD through castor litter fall was significant to improve marginally the nitrification inhibition per cent which was similar to 50% RDF + 50% RON through jatropha litter fall compared to RDF. The microbial biomass, dehyogenase activity and FDA hyolysis activity (60 DAS) has improved with the application of 80 kg through castor and jatropha litter fall, respectively.