不同磷水组合对紫云英苗期养分吸收及根瘤固氮的影响

Effects of Different Phosphorus and Water Combinations on Nutrient Absorption and Nodule Nitrogen Fixation of Chinese Milk Vetch(Astragalus sinicus L.)Seedlings

采用盆栽试验,设置4个土壤水分梯度(田间持水量的25%、50%、75%和100%,分别用W 1、W 2、W 3和W 4表示)及4个施磷量水平(0、30、60和90kg/hm^(2),分别用P 0、P 1、P 2和P 3表示),研究不同土壤水分条件下施磷对紫云英(Astragalus sinicus L.)苗期生长、养分积累、根瘤固氮酶活性的影响。结果表明,W 3处理下的紫云英苗期各项指标显著优于其他水分处理。适度增施磷肥显著增加了紫云英苗期生物量,促进了全氮、全磷积累量及根瘤固氮酶活性的增加,但在高磷条件下会产生负效应,导致紫云英生物量显著下降。土壤水分和施磷量之间存在极显著的互作效应,磷肥效应随着土壤含水量的增加呈先上升后下降的趋势。W 3P 2处理下的紫云英生长较好,表现出最优的生物量、全氮、全磷积累量及根瘤固氮酶活性。综上所述,土壤相对含水量为75%、施磷量为60kg/hm^(2),是适宜紫云英苗期生长的最优“磷-水”组合。

Four soil water gradients(25%,50%,75%,and 100%of the field water holding capacity,represented by W 1,W 2,W 3,and W 4,respectively)and four phosphorus application levels(0,30,60,90 kg/hm^(2),represented by P 0,P 1,P 2 and P 3,respectively)were set up in a pot experiment to explore the effects of phosphorus application on the growth,nutrient accumulation,and nodule nitrogenase activity of Astragalus sinicus L.seedlings under different soil moisture conditions.The results showed that the various indexes of A.sinicus L.seedlings under the W 3 treatment were significantly better than those of other water addition treatments(P<0.05).Moderate phosphorus application significantly increased the biomass,nitrogen and phosphorus accumulations,and nodule nitrogenase activity of A.sinicus L.seedlings(P<0.05).However,excessive phosphorus resulted in a significant decrease in biomass of seedlings(P<0.05).There was a significant interaction between soil moisture and phosphorus(P<0.01)that the effect of phosphorus increased first and then decreased with the increased of soil water content.The A.sinicus L.seedlings exhibited optimal growth under W 3P 2 treatment,characterized by improved biomass,nitrogen and phosphorus accumulations,and nodule nitrogenase activity.In summary,75%of soil relative water content and 60 kg/hm^(2) phosphorus application were the optimal combination of phosphorus and water for the growth of A.sinicus L.seedlings.