The influence of rate and form of mineral nitrogen on seedling growth symbiotic nitrogen fixation and mineral nitrogen assimilation in desmodium intortum cultivar greenleaf
Kitamura, Y.; Nishimura, S.
Grassland Science 26(3): 290-296
ISSN/ISBN: 1744-6961 Accession: 006699943
The effects of NH4-N, NO3-N and NH4NO3-N on seedling growth, nodule formation, symbiotic [Rhizobium] N2 fixation and mineral-N assimilation of D. intortum cv. Greenleaf were investigated under controlled conditions. The rate of mineral-N application influenced the DM [dry matter] yield but the form of mineral-N did not. As N rates increased, total nodule number and weight were positively affected with NH4-N, but not with NO3-N. Weight per nodule increased with higher rates of NO3-N, but not with NH4-N application. Plant N from symbiotic N2-fixation increased linearly with NH4-N, and decreased with NO3-N application. N originating from mineral-N increased linearly with increasing rates of N application in the following order: NO3-N > NH4NO3-N > NH4-N. NH4-N is a better source of N for starter N.