有机碳输入的改变对红壤恢复林地土壤养分和酶活性的影响

Effects of changes in organic carbon input on soil nutrients and enzyme activities in restoration forests of red soil

以亚热带红壤退化地恢复形成的木荷纯林、马尾松纯林和木荷与马尾松混交林为研究对象,设置保留凋落物+保留根系+保留菌根(L+R+M,对照)、凋落物加倍+保留根系+保留菌根(2L+R+M)、去除凋落物+去除根系+保留菌根(NL+NR+M)、去除凋落物+去除根系+去除菌根(NL+NR+NM)和去除凋落物+保留根系+保留菌根(NL+R+M)5种处理,探讨改变有机碳输入对土壤养分和酶活性的影响。结果表明:土壤pH和全氮含量受林分类型影响(P<0.05),其中混交林最高;土壤pH和养分在不同处理间无显著差异(P>0.05)。土壤蔗糖酶活性亦受林分类型影响(P<0.05),其中木荷林最大;木荷林NL+NR+M和NL+NR+NM处理使多酚氧化酶活性分别提高了95.31%和95.16%(P<0.05),而脲酶、酸性磷酸酶和酸性转化酶活性对林分类型和有机碳输入改变的响应均不敏感。土壤蔗糖酶、酸性转化酶活性与土壤pH负相关,蔗糖酶、脲酶活性与有机质、速效磷含量正相关。

Our research focuses on the typical stands of Schima superba pure forest,Pinus massoniana pure forest and mixed forest of Schima superba and Pinus massoniana recovered from eroded and degraded red soil in a subtropical region.Five treatments were set as follows:retaining litter+retaining root+retaining mycorrhiza(L+R+M,control treatment),doubling litter+retaining root+retaining mycorrhiza(2L+R+M),removing litter+removing root+retaining mycorrhiza(NL+NR+M),removing litter+removing root+removing mycorrhiza(NL+NR+NM),and removing litter+retaining root+retaining mycorrhiza(NL+R+M).We discussed the effects of changes in organic carbon input on soil nutrients and enzyme activities.The results show that soil pH and total nitrogen content were affected by stand types(P<0.05),and the highest in the mixed forest.There was no significant difference in soil pH and nutrients among different treatments(P<0.05).The soil sucrase activity was also affected by stand type(P<0.05),and the highest in Schima superba forest.NL+NR+M and NL+NR+NM treatments of Schima superba forest increased the soil polyphenol oxidase activities by 95.31%and 95.16%,respectively(P<0.05).However,the activities of soil urease,acid phosphatase and acid invertase were not sensitive to the changes of stand types and organic carbon inputs.The soil invertase and acid invertase activities were negatively correlated with soil pH,and the invertase and urease activities were positively correlated with soil organic matter and available phosphorus.