硒肥对豆科牧草圆叶决明生长和植株养分含量及其固氮能力的影响

Effects of selenium on Chamaecrista rotundifolia growth,nutrient absorption and nitrogen-fixing ability.

通过田间小区试验,研究了施用不同量硒肥对种植于南方红壤的圆叶决明植株生长、牧草品质和根瘤固氮能力的影响.结果表明,1hm2施用硒肥75g(S1)、150g(S2)、225g(S3)、300g(S4)处理的圆叶决明植株株高、分枝数、根干重和茎叶干重分别比不施硒肥的对照(S0)处理提高0.3%～6.2%、65.1%～79.5%、155%～252%和23.5%～70.6%,其中以S2处理最佳.施用4种水平硒肥处理(S1～S4)的植株全氮、全磷和全钾吸收量分别比对照(S0)处理提高21.79%～41.46%、20.74%～34.67%和34.3%～62.4%;而圆叶决明植株粗蛋白、粗脂肪、粗纤维和氨基酸含量则分别比对照(S0)处理提高了21.79%～41.46%、1.4%～89.6%、34.1%～56.6%和6.33%～63.24%,其中以S2处理对提高圆叶决明植株营养成分含量的效果最为明显.S4处理的圆叶决明植株体硒含量最高,达0.695mg·kg-1,比不施硒肥的S0处理提高了0.658mg·kg-1.在S2处理中,圆叶决明的根瘤重、根瘤数和根瘤固氮酶活性均呈现为最大值,分别比对照(S0)提高了131.7%、114.3%和1417.9%.

In this paper,a field experiment was conducted on a red soil of South China to study the effects of applying selenium fertilizer on the growth,forage quality and nitrogen-fixing ability of Chamaecrista rotundifolia. The results showed that applying 75,150,225 and 300 g Se·hm^(-2) could increase the plant height,branch number,dry root weight and dry forage yield by 0.3%～6.2%,65.1%～79.5%,155%～252% and 30.6%～54.1%,respectively. The total nitrogen,total phosphorus and total potassium contents of plant were increased by 21.79%～41.46%,20.74%～34.67% and 34.3%～62.4%,respectively,and the raw protein,raw fat,raw fiber and amino acid contents were increased by 21.79%～41.46%,1.4%～89.6%,34.1%～56.6% and 6.33%～63.24%,respectively. Among the 4 doses,150 g Se·hm^(-2) was the most effective and suitable application amount. The selenium content in plant after applying 300 g Se·hm^(-2)(S_4) was 0.695 mg·kg^(-1),with an increase of 0.658 mg·kg^(-1) compared to no selenium fertilization. There was a significantly positive correlation between plant selenium content and applied selenium (R^2=0.9666^(**)). The root nodule weight,number and nitrogenase activity in treatment 150 g Se·hm^(-2)(S_2) were respectively 131.7%,114.3% and 1 417.9% higher than those of no selenium fertilization. The correlation between applied selenium and nitrogenase activity was also significant (R^2=0.9606~*).