Biological nitrogen fixation in Crotalaria species estimated using the 15N isotope dilution method

Abstract

A greenhouse experiment was conducted to measure nitrogen fixation in three Crotalaria species : C. ochroleuca, C. perrottetii and C. retusa growing in Senegal by using 15 N direct isotope dilution technique. Two non-fixing plants, Senna obtusifolia and Senna occidentalis served as reference plants. The amount of nitrogen fixed two months after planting was obtained using the average of the two reference plants. The atom % 15 N excess in the Crotalaria species was significantly lower than that of the reference plants, indicating that significant nitrogen fixation occurred in the three plants. Significant differences were observed between the Crotalaria species; C. ochroleuca yielded more dry matter weight and total nitrogen than did C. perrottetti and C. retusa. The % nitrogen derived from atmosphere (%Ndfa) in leaves and stems was also higher in C. ochroleuca. There was no significant difference in %Ndfa in the whole plant between the three Crotalaria species (47% to 53%). In contrast, interspecific variability was observed based on the %Ndfa. C. ochroleuca significantly exhibited the higher amount of total nitrogen fixed, equivalent to 83 kg of nitrogen fixed per hectare. Based on these data, it was concluded that C. ochroleuca could be used in multiple cropping systems in Senegal for making more nitrogen available to other plants.

Chromosomal Characterization and First Report of Aneuploidy in <i>Crotalaria</i> spp. from Bangladesh

“…Apart from the use as a green manure crop, it is also used as fodder, weed suppressor, ground cover crops, a suitable indigenous raw material for manufacturing of various products, potential biofuel crop, medicinal purposes, etc. (Chaudhury 1950, Mukherjee 1953, Rupper 1987, Pradhan et al 1999, Samba et al 2002, Ghani 2003, Ahmed et al 2009, Bhatt et al 2009, Kumar and Saumil 2014, Sarkar et al 2015.…”