凋落物中次生代谢物对森林土壤可溶性氮的影响

通过外加性质不同的凋落物以及不同浓度的单宁酸,于武夷山不同海拔高度的森林土壤中进行培养,研究森林凋落物中次生代谢物对土壤可溶性氮(N)的影响。结果显示,土壤经加入凋落物处理,其可溶性N含量降低。加入杉木凋落物使红壤可溶性N含量降低12.0%～27.5%,杉木较竹叶凋落物处理降低作用显著(p0.05);对黄红壤添加不同浓度单宁酸处理显示,与对照比较,高浓度单宁酸可显著(p0.001)降低土壤可溶性N含量,降低幅度在40.6%～48.1%,而低浓度单宁酸对土壤可溶性N的影响不显著。表明植物凋落物,尤其是杉木对土壤可溶性N的影响很可能与其本身单宁酸含量差异有关,从而影响了土壤可溶性有机N和无机N的转化。

Effect of secondary metabolites of litter on soluble nitrogen in forest soils

By adding different litters and tannic acid with different rates to forest soils from Wuyi-Mount under cultivate condition, the effects of secondary metabolism on soil soluble nitrogen was studied. The results showed that soluble nitrogen content decreased by adding litters. Soluble nitrogen decreased by 12.0% - 27.5% for red soil with the addition of fir litter. The effect (p<0.05) of fir litter treatment on soluble nitrogen content was higher than that of bamboo. Compared with control, the treatments with high rate of tannic acid significantly (p<0.001) reduced soluble soil nitrogen of yellow-red soil with a decrease by 40.6% - 48.1%, but the effect of low rate of tannic acid on soil soluble nitrogen was not significant. The results indicated that the effects of litters, particularly fir litter, on soil soluble nitrogen possibly depend on tannic acid, which affects the soil organic and inorganic nitrogen turnover in soil.