Estimation of nitrogen fixation by blackgram using 15n techniques
1998
Pilbeam, C.J. | Tripathi, B.P. | Acharya, G.P. (Lumle Agricultural Research Centre, Pokhara, Kaski (Nepal))
Legumes are important crops to fix atmospheric nitrogen in their root nodules and after decomposition of nodules, nitrogen is utilized by the crops. The objectives of this study were to estimate the proportion of N in the blackgram crop derived from fertilizer, soil and fixation of atmospheric N using 15N techniques, to identify a suitable non-legumenous reference crop for estimating N-fixation by blackgram and to measure the effect of an application of lime on the growth and N-fixation capacity of blackgram. The result showed that liming did not significantly produce high total dry matter or pod yields of blackgram. Total dry matter yield of niger varied from 1400 to 1600 kg per hectare depending on the sampling time while its yield of pods was constant. Liming did not increase N content of blackgram. Niger contained more N than blackgram. Nitrogen fixed by blackgram increased 0.53 percent at physiological maturity to 0.67 percent at final harvest. Less than 1 percent of the N in a blackgram crop came from fertilizer, 30 to 45 percent came for the soil and more than 95 percent of the N in niger came from the soil and the rest was taken up from fertilizer.
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