封育对草地植被功能群多样性及土壤养分特征的影响

Effects of Enclosure years on Vegetation Functional Groups Diversity and Soil total Nutrients Characters of Sandy Desert Grassland

为探究不同封育年限下植被功能群、土壤养分及其化学计量学特征的变化规律,对封育0a(En0,对照)、3a(En3)、5a(En5)、8a(En8)的沙质荒漠草地植被功能群多样性、土壤有机碳(Soil organic carbon,SOC)、全碳(Total carbon,TC)、全氮(Total nitrogen,TN)、全磷(Total phosphorus,TP)、全钾(Total kalium,TK)及其化学计量学特征进行测定。结果表明:封育提高了沙质荒漠草地植物功能群Patrick指数(Pa)、Simpson指数(D)和Shannon-Wiener指数(H),对Pielou均匀度指数(Jsw)影响不显著。封育后0~50cm土层TC含量增加,且0~5cm显著增加,而5~30cm土层SOC在En5处显著降低。封育后5~50cm土层的TN显著降低,而TP、TK含量则呈"升-降"趋势,En3达到最高,显著高于En0。与En0比,0~5cm土层En3土壤C∶N值增加显著,而En3处理0~50cm土层N∶P值最低。沙质荒漠草地封育过程中,土壤TP、TN含量对土壤养分的恢复及植被多样性的维持具有重要指示作用。适时封育有利于沙质荒漠植被功能多样性及土壤养分的恢复。

The vegetation functional groups,soil total nutrients and stoichiometric characteristics in different enclosure years of sandy desert grassland,the diversity of function community,soil organic carbon,total carbon,total nitrogen,total phosphorus,total kalium and ecological stoichiometric characteristics under zero enclosure years（control）,three enclosure years,five enclosure years and eight enclosure years were studied.The result showed that the function community Patrick evenness index,Simpson index and Shannon-Wiener index with increase enclosure years were improved,and Pielou evenness index was not significantly changed.The soil total carbon in 0~50 cm was increased and the soil total carbon in 0~5 cm increased significantly with increased enclosure years.Soil organic carbon content in the 5~30 cm layer was significantly decreased after five enclosure years.Total nitrogen in 5~50 cm layer was significantly decreased.Total phosphorus and total kalium were increased first and then decreased under the condition of fencing,reached the highest after three enclosure years.Compared with control group the ratio of soil organic carbon and total nitrogen in 0~5 cm layer were significantly increased.But the ratio of total nitrogen and total phosphorus in 0~50 cm layer reached the lowest after three enclosure years.The results showed that the soil total phosphorus and total nitrogen had a directive for the soil nutrients recover and vegetation diversity maintenance.Therefore,the suitable enclosure years is beneficial for the soil nutrients and vegetation recover of sandy desert grassland.