摘要
Long-term growth of artificial pure forest will lead to continuous planting obstacle. The best solution is to form mixed forest through introducing other regenerated tree species. In order to direct the option of mixed tree species and ratios on upper reach of Minjiang river, sltu incubations of soil mixture of depth O-lOcm （humus soil of coniferous with deciduous tbrest, in this way to model mixed-forest） of typical forests of Cercidiphyllum japonicum（L）, Betula utilis（H）, Pinus yunnansinsis（M） and Picea asperata（Y） were carried out and the interspecific relationships were studied through analyzing the influences of soil mixing on the biochemical characteristics of soil and Jitter decomposition. The results can be concluded as following： （1） In forestlands of C.japonicum, P.yunnansinsis amt P.asperata, enzyme activities of urease, invertase and catalase of soil were intensified after soil mixing. Whereas, in forestland of B.utilis, all the three enzyme activities of soil were decreased after mixing with soil of P.yunnansinsis, but after mixing with soil of P.asperata, enzyme activities of urease and catalase were intensified and enzyme activity of invertase was decreased （2） Litter decomposition were popularly advanced after soil mixing. In forestlands of C.japonieum, P.yunnansinsis, the contents of organic-C and total N in soil were increased after soil mixing. Whereas, in forestland of B.utilis and P.asperata, the contents of N in soil were increased while organic-C decreased after soil mixing. （3） The acidities or alkalinity of soil were neutralized and further intensified after soil mixing, which means that soil of deciduous forest develops toward acidity while soil of coniferous forest develops toward to alkalinity. （4） Mixed ratios of LM0.15-0.50 and LY0.15-0.35 in forestland of C.japonicum, HM0.15 and HY0.15-0.50 in forestland of B.utilis, MI.,0.15-0.50 and MH0.35-0.50 in forest/and of P.yunnansinsis, YL0.35-0.50 and YH0.35 in forestland of P.asperata are betterchoice for soil mixing relatively, which can be taken as reference in decision of introducing regenerated tree species and ratio of mixed forest in practice.
