Abstract: Nitrogen (N),phosphorus (P) and potassium (K) are the three most important nutrient elements for plant growth. This study studied the effects of nitrogen,phosphorus and potassium on the growth of two Chamaecrista spp,aiming to provide scientific basis for the application of two Chamaecrista spp. In this study,five fertilization treatments of nitrogen,phosphorus and potassium were set,respectively,to investigate the changes of biomass and agronomic traits (plant height,root length,root weight,pod number,nodule number,etc.) of Chamaecrista rotundifolia and Chamaecrasta nictitans,and the relationships between biomass,pod number,nodule number and fertilization were studied. The results showed the significant differences of biomass and nodule numbers were observed in two Chamaecrista spp between fertilizer applications. Different regression models could be used for two Chamaecrista spp.to meet the relationship between the fertilization (N,P and K) and biomass,nodule numbers and pod numbers. The best performance about comprehensive traits of the two Chamaecrista spp was observed under low N,P and K fertilizer application than others. With the increase of fertilizer application,the biomass decreased,and agronomic traits were worse than those of low fertilizer application. The better comprehensive performance was observed in C. nictitans than in C. rotundifolia. The regression equations of biomass and agronomic traits of C. rotundifolia and C. nictitans were Y=61.16+0.121X1+0.209X2-1.669X4+6.351X5 and Y=110.38+0.151X1-2.02X4,respectively. The order of decision coefficients of C. rotundifolia from large to small was nodal number > root dry weight > pod number > root length.,and the order of decision coefficients of C.nictitans from large to small was pod number > root length,among which root length was negatively correlated with biomass of two Chamaecrista spp. The comprehensive traits of C.rotundifolia treated with N1 (36 kg·hm^-2),P1(96 kg·hm^-2) and K1(60 kg·hm^-2) were better than others,and C. nictitans treated with N0 (0 kg·hm^-2),P1(96 kg·hm^-2) and K1(60 kg·hm^-2) had the nice comprehensive traits.

Key words: Fertilizer application, Legume green manure, Growth performance, Regression equation, Path analysis, Decision coefficient

摘要： 为了探讨氮、磷和钾对决明（Chamaecrista）生长的影响，本研究分别设置氮、磷和钾肥的5个施肥水平，研究不同施肥量下2种决明生物量、农艺性状的变化，以及生物量、结荚数和结瘤数与施肥量的关系。结果表明，施肥量与2种决明生物量、结荚数和结瘤数可用不同的回归模型拟合，低量N，P，K处理2种决明的综合性状表现佳，随着施肥量增加，生物量和农艺性状指标降低，羽叶决明（Chamaecrasta nictitans）综合性状优于圆叶决明（Chamaecrista rotundifolia）。生物量与圆叶决明、羽叶决明农艺性状的回归方程分别为Y=61.16+0.121X1+0.209X2-1.669X4+6.351X5和Y=110.38+0.151X1-2.02X4，决策系数从大到小的顺序分别为“结瘤数>根干重>结荚数>根长”和“结荚数>根长”。圆叶决明施肥以N1（36 kg·hm^-2），P1（96 kg·hm^-2）和K1（60 kg·hm^-2）较为理想；羽叶决明施肥以N0（0 kg·hm^-2），P1（96 kg·hm^-2）和K1（60 kg·hm^-2）较为理想。

关键词: 施肥量, 豆科绿肥, 生长性能, 回归方程, 通径分析, 决策系数