Abstract:Effects of boron on the growth, nutrition quality and nitrogen-fixing ability were studied in Chamaecrista rotundifolia. Compared with control,the branching numbers, root and shoot biomass of C. rotundifolia treated with boron (1.5 kg hm-2, 3.0 kg hm-2, 4.5 kg hm-2) were increased by 15.7%-36.7%, 251%-493% and 7.2%-34.2%, respectively. The boron treatment of 1.5 kg hm-2 was the best. The contents of total nitrogen, phosphorus, potassium, raw proteins, raw fatty acids, raw fibers and amino acids were increased by 8.80%-31.38%, 10.37%-31.26%, 18.4%-37.9% 15.6%-65.4%, 10.5%-33.7% and 1.43%-42.60%, respectively, in boron (1.5, 3.0 and 4.5 kg hm-2 ) treatments than controls. The effect of 1.5 kg hm-2 boron treatment was also the best. It was suggested that the appropriate boron was benefit to nutrient absorption and accumulation in C. rotundifolia. The experiment also showed that boron content of the species was highest after 4.5 kg hm-2 boron treatment. Root nodule weight, number and nitrogenase activity reached highest levels after 3.0 kg hm-2 boron treatment. The comprehensive analysis showed that 1.5 kg hm-2 boron treatment was more suitable under the experiment condition.