农林复合杨树土壤养分的根际效应

用对比试验的方法,研究农林复合中杨树+留兰香、杨树+小麦、杨树+红薯和杨树纯林4种林地的杨树生长量、林地土壤物理性状和土壤养分以及杨树和间作物养分的根际效应。结果表明:1)杨树+留兰香林地的杨树生长量明显小于对照,显著小于杨树+小麦和红薯林地;2)间作林地的土壤物理性状、土壤pH值、非根际土壤养分不是影响杨树生长的关键因素,而根际土壤养分及根际效应的变化对杨树生长有直接影响;3)在杨树根际土壤中,杨树+小麦和红薯林地杨树根际土壤养分质量分数均高于对照;杨树+留兰香林地的杨树根际土壤有机质和速效磷质量分数高于对照,速效钾和速效氮质量分数则低于对照,而留兰香的根际养分质量分数除速效氮外均高于小麦和红薯;4)从养分的根际效应来看,杨树+留兰香林地杨树的养分根际效应值除有机质外小于对照并小于留兰香,杨树+小麦林地杨树的养分根际效应值除速效磷外均大于对照并大于小麦,杨树+红薯林地杨树的养分根际效应值除速效磷外均小于对照,除速效氮外均大于红薯。

The rhizosphere effects of soil nutrient on Populus agroforestry ecosystems

By comparative investigation,the populus growth,soil physical properties,soil nutrient,and the rhizosphere effects of soil nutrient between populus and intercrops were studied in 3 agroforestry ecosystems,which intercropped mentha spicata,Triticum aestivum,Ipomoea batatas,respectively.Pure populous plantation was chosen as the control.The result showed that the populus growth in agroforestry ecosystems intercropping mentha spicata was obviously lower than other three stands.The key factor that influenced Populus growth were soil nutrients of the rhizosphere and rhizosphere effect variation,rather than soil physical properties,soil pH value and soil nutrients of the non-rhizosphere.In the rhizosphere soil,the soil nutrient content of intercropping triticum aestivum and ipomoea batatas was higher;but soil organic matter and available P content in rhizosphere of intercropping mentha spicata were higher than that of pure stand,while soil available K and N presented inverse tendency.For the intercrops,the soil nutrient content except available N of mentha spicata were all higher than that of triticum aestivum and ipomoea batatas.With respect to the rhizosphere effect of soil nutrients,soil nutrients except the soil organic matter in intercropping mentha spicata were all less than that of the pure plantation and mentha spicata,soil nutrients except the available P in intercropping triticum aestivum were all higher than that of pure plantation and triticum aestivum,soil nutrients except the available P in intercropping ipomoea batatas were all lower than that of pure plantation,and higher than that of ipomoea batatas except the available N.