三峡库区不同植被覆盖对土壤氮的影响

Effects of Different Vegetation Cover on Soil Nitrogen in Three Gorges Reservoir

不同植被类型影响着土壤养分的积累、分布与循环,而土壤氮素是植被生长的重要限制性元素。通过分析宜昌点军区3种植被类型(柏树地、橘树地、菜地)覆盖下土壤氮素的变化情况,研究了不同植被对土壤氮素各形态的影响。结果表明,土壤全氮、硝态氮和微生物氮都是柏树地显著大于菜地和橘树地,而菜地和橘树地之间无显著性的差异;土壤矿化氮和微生物氮/全氮的变化顺序是柏树地>橘树地>菜地。说明不同植被覆盖对土壤氮有显著的影响,柏树地更有利于土壤氮的积累,氮的有效性也最高,由此认为柏树长期生长有益于土壤氮的改善。

The types of vegetation cover make an important impact on the accumulation, distribution and circulation of soil nutrient. While the content of soil nitrogen had great influence on the growth of the vegetation. Take the analysis of the changes of soil nitrogen covered by 3 vegetation types（cypress site, citrus tree site, vegetable site） in Yichang to study the influence of different vegetation on soil nitrogen in various forms. The results showed that soil total N, microbial biomass N、nitrate N were higher under cypress site than those under vegetable site to citrus tree site which had no significant difference.Soil mineralization N and microbial biomass N / total N followed as cypress site vegetable site citrus tree site. All above showed that the long-term growth cypress could improved soil nitrogen.