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100			_aPrasannakumari P
245		0	_aEstimates of nitrogen fixation by legume cover crops grown in young rubber plantations using 15N isotope dilution technique
260			_bJournal of Plantation Crops _c2014
300			_a205-209
520			_a15N Isotope dilution technique has been used to estimate the amounts of N2 fixed by leguminous cover crops, Pueraria phaseoloides and Mucuna bracteata grown in the inter-rows of immature rubber plantations, using Ipomoea batatas as the reference plant. The field experiment was conducted in the RRII farm during 2009, in an area planted with Hevea brasiliensis, clone RRII 105. The cover crops and the reference plant were established in separate blocks. For labeled urea application, micro-plots (Im x Im) were established and 15N labeled urea, 5 atom;15N excess, was applied @ 5kg ha-1. After 45 days, the above ground biomass from the micro-plots was harvested, weighed and sub-samples were collected for determination of dry matter accumulation, N content and 15N enrichment. Micro-plot experiments were conducted thrice during the active growth period of the legumes and the reference plant, i.e., during June-July, August-September and October-November. Estimates of N2-fixation for P. phaseoloides ranged from 79.82 kg N ha-1 during June-July to 39.32 kg N ha-1 during October-November and averaged 58.1 kg ha-1. Corresponding estimates for M. bracteata ranged from 83.95 kg N ha-1 during June-July to 57.03 kg N ha-1 during October-Nov and averaged 69.7 kg N ha-1. The study showed that both the cover crops fixed considerable quantities of atmospheric nitrogen and that N2 fixation by M. bracteata was higher than that of P. phaseoloides.
650			_a15N isotope dilution technique
650			_aM. bracteata
650			_aN2 fixation
650			_aP. phaseoloides
700			_aJessy M D
700			_aJoseph M
700			_aPhilip A
942			_cJS
999			_c58802 _d58802