ABSTRACT
A study was carried out to identify the relationships between added fertilizer nitrogen and nodulation characteristics, plant growth and nitrogen content of three common tropical rangeland legumes. The selected legumes were Desmodium, Pueraria and Siratro.
The response of all characters to added fertilizer nitrogen varied with species. Nodulation was initiated earlier at low levels of fertilizer nitrogen in Pueraria. In contrast, Desmodium, the species with the highest plant nitrogen content required the greatest quantity of fertilizer nitrogen for early nodule initiation. Nodule number was highest in Desmodium at a higher rate of fertilizer nitrogen than in the other two species. Plant growth and nitrogen contents were maximized at rates of fertilizer that exceeded those required for optimal nodulation. The relationships between fertilizer nitrogen and the measured parameters are presented in terms of their practical significance, as the nitrogen requirements of different legumes for nodulation and growth varied.
