干旱河谷-山地森林交错带植被调控模式对土壤氮、磷强度及库的影响

Effects of Vegetation Modified Mode on the Soil Nitrogen and Phosphorus Content Characteristics at Ecotone between Dry Valley and Motone Forest

以调控30个月的4种典型调控模式以及未调控退耕纯林为研究对象,比较分析了不同调控模式下氮、磷供强度及库容特征。结果表明,相对于纯林模式,4种调控模式均可有效缓解缺氮少磷的土壤现状,提高或增加了固氮效率以及氮、磷储量,且表现出氮、磷元素聚表分布(0-10cm)的特征;表层土(0-10cm)中,刺槐+扁桃+紫花苜蓿模式的氨态氮含量(10.52±0.34g/kg)、硝态氮含量(11.69±1.06g/kg)显著高于其它模式,对植物生长极为有利,但对氮、磷的储存贡献较小;刺槐+新疆杨+早熟禾模式可显著提高固氮效率;刺槐+高山柳+早熟禾模式的土壤全氮含量显著高于其它模式(7.33±0.38g/kg),而刺槐+岷江柏+早熟禾对土壤氮、磷环境的改善相对于其他模式较差。综上认为,以新疆杨作为乔木、刺槐为高灌木、高山柳为伴生种、紫花苜蓿作为林下草种是适合于EDM土壤与气候环境的最佳模式之一。

We chose four modified mode in EDM that Robinia pseudoacacia is constructive species,and chose Mangifera persiciforma,Medicago sativa,Cupressus chengiana,Poa pratensis,Populus bolleana,Salix cupularis as the modifed species in 2009.Meanwhile,we analysed and compared the nitrogen and phosphorus characteristics of four modified mode just used pure locust forest as the comparison group.The results observed that,four modified modes,compared to locust pure forest,can accelerated the efficiency of nitrogen fixing and added the pool of nitrogen and phosphorus.The different forming of nitrogen and phosphorus were all accumulated in surface soil layer,specially in 0-10 cm layer.In 0-10 cm layer,the ammonium nitrogen（10.52±0.34 g/kg） and nitrate nitrogen（11.69±1.06 g/kg） of soil in the combination（Robinia pseudoacaci＋ Mangifera persiciforma ＋ Medicago sativa） was significant higher than other three midified modes.In contrast,this mode had lower contribution to the deposition of nitrogen and phosphorus.The mode（Robinia pseudoacacia＋ Populus bolleana＋ Poa pratensis） can significant increased the accumulation of nitrogen than other modes.The content of total nitrogen（7.33±0.38 g/kg） in the mode（Robinia pseudoacacia＋ Salix cupularis＋ Poa pratensis） showed higher than other modes.But,the mode（Robinia pseudoacacia＋ Cupressus chengiana＋ Poa pratensis） did not observed positive efficiency to soil nitrogen and phosphorus.Therefore,Populus bolleana can be the best modified arbor,Robinia pseudoacacia is still the high shrub and Salix cupularis is the following shrub species.Medicago sativa is the best undergrown plant.The modified mode that conbine these modified species（i.e.,Populus bolleana,Salix cupularis,Robinia pseudoacacia,Medicago sativa） might be obtain good ecological benefit in the soil environment of EDM.