施肥对苗期紫茎泽兰和黑麦草相对竞争力的影响

为种植黑麦草替代控制紫茎泽兰提供依据,运用取代实验法,研究了施肥(氮、磷)对苗期紫茎泽兰和黑麦草的相对竞争力以及生长表现的影响。结果表明:增施氮肥和磷肥均能够提高紫茎泽兰的相对竞争力,而仅磷肥对黑麦草的竞争力略有促进作用;但在各种施肥水平下,黑麦草的竞争力仍然明显强于紫茎泽兰。增施氮肥可以显著提高紫茎泽兰的株高、分枝数和干质量,而磷肥仅在较高时才显著提高其干质量;增施氮肥虽然可以提高黑麦草的分蘖数量,但对其干质量没有影响,而增施磷肥(2次)可以显著提高其干质量;在竞争中紫茎泽兰植株生长的能量分配(用根茎比表示)对磷肥不敏感。建议适当增施磷肥、不施或少施氮肥,以提高黑麦草的替代控制效果。

Effects of fertilization on the relative competitive ability of Eupatorium adenophorum and Lolium perenne at their seedling stage

To test the suppressive ability of replacement species Lolium perenne on invasive alien species Eupatorium adenophorum,a field experiment was conducted to study the effects of applying fertilizers N and P on the relative competitive ability and growth performances of these two species at their seedling stage.The results showed that the competitive ability of E.adenophorum was enhanced after applying N and P as measured by the relative competition intensity(RCI),while that of L.perenne was only slightly enhanced with the application of P.However,L.perenne was more competitive than E.adenophorum under any treatments of fertilization.Fertilizer N increased the plant height,branch number,and dry biomass of E.adenophorum significantly,and only high application rate of fertilizer P increased the dry biomass.The tiller number of L.perenne was increased but its dry biomass was unchanged under the higher application rates of N,while the dry biomass was increased significantly by the higher application rates of P.E.adenophorum was not sensitive to the application rates of P in its energy allocation as measured by the root/shoot ratio.It was suggested that more application of P and no or less application of N could enhance the replacement of E.adenophorum by L.perenne.