甘肃环县沙化区不同植被类型对土壤养分的影响

Effects of different vegetation types on soil nutrientin desertification area of Huan county,Gansu province

摘要:

为探讨不同植被恢复类型对土壤养分的影响,选择甘肃省环县沙化区为研究区域,以立地条件一致、栽植5 a的河北杨(Populus hopeiensis)(PHF)、柠条(Caragana korshinskii)(CKF)、爬地柏(Sabina procumbens)(SVF)林地为研究对象,设置样地,分别采集0~20、20~40、40~60 cm土层土样,测定植被土层的养分指标,并分析变化规律和差异性。结果表明:(1)3种植被类型的土壤铵态氮、硝态氮、速效磷含量“表聚效应”显著,CKF、SVF林地有机碳、全氮含量在不同土层差异显著。(2)在0~20 cm土层,CKF和SVF的有机碳、全氮、硝态氮、铵态氮、速效钾含量均显著高于PHF;在20~40 cm土层,CKF林地有机碳、全氮含量显著高于PHF,3种植被类型间硝态氮和铵态氮含量均存在显著差异,表现为CKF林地＞SVF林地＞PHF林地,SVF林地速效钾含量显著高于其他2种类型。(3)3种植被类型的C/N、N/P均低于我国土壤的平均水平,土壤碳、氮水平较低,在0~40 cm土层,CKF的C/P和N/P显著高于PHF。(4)主成分分析得出3种植被恢复类型的土壤养分状况表现为SVF＞CKF＞PHF。爬地柏可作为该区植被恢复的优选树种。

Abstract:

To explore the effect of vegetation types on soil nutrients,the desertification area of Huan county,Gansu province was chosen as the research area,Populus hopeiensis forest (PHF),Caragana korshinskii forest (CKF) and Sabina procumbens forest (SVF) planted at the same time under similar site conditions were taken as the research objects.,Ssoil samples in 0~20 cm,20~40 cm and 40~60 cm layers were collected to measure and analyze the change and difference in nutrient index among vegetation types and soil layers.Results showed that:(1) Nitrate nitrogen,ammonium nitrogen and available potassium in the three vegetation types showed obvious surface accumulation effects.(2) The effect of vegetation types on soil nutrient differed with the change of soil depth.,Iin 0~20 cm layer,the content of organic carbon,total nitrogen,nitrate nitrogen,ammonium nitrogen and available potassium in CKF and SVF were significantly higher than those in PHF.In 20~40 cm layer,nitrate nitrogen and,ammonium nitrogen were markedly different among three vegetation types,taking in the order of CKF ＞SVF ＞PHF.,Tthe content of organic carbon content in CKF was significantly higher than that in PHF,and the available potassium in SVF was obviously higher than the other two types.(3) C/N and N/P in three vegetation types were lower than the national average.,indicating Tthe level of C and N was low,and C/N and N/P in CKF were significantly higher than those in PHF in the layer of 0~40 cm.(4) Principal component analysis showed that the soil nutrient of the three vegetation types was as follows:SVF＞CKF＞PHF.ThereforeThe results suggest,S.abina procumbens can be used as the preferred tree species for vegetation restoration in this area.