我国南亚热带几种人工林的生物物质循环特点及其对土壤的影响

通过对杉木、马尾松、红荷木、格木四种人工林的三年定位研究,初步获得了四种林木对主要营养元素的生物吸收和归还特点、对土壤养分状况、水分状况、微生物状况和土壤酶活性的影响等一系列资料。初步阐明了四种林木凋落物的数量及主要营养元素含量,研究了四种林木凋落物的分解特点。从而为进一步研究林木混交提供了科学依据。研究表明,阔叶树种与针叶树种相比,在改善土壤理化性状、提高土壤生产力等方面都表现出明显的优点。

CHARACTERISTICS OF THE BIOLOGICAL MATERIAL CYCLING OF SEVERAL TYPES OF ARTIFICIAL FORESTS AND THEIR INFLUENCE ON SOILS IN SOUTH SUBTROPICAL CHINA

The artificial forests existing in southern subtropical China consist chiefly of China fir and pines.Continuous reforestation of coniferous trees has resulted in the deterioration of soil conditions and decreased the production of forestry.For improvement of the forest soil and production of forestry,a three-year location experiment on material cycling of the establishing artificial forests of Cunninghamia lanceolata,Pinus massoniana,Schima wallichii and Eryahro-phloeum tordii on lateritic red earth in Nanning was conducted.Results of the experiment showed that the four types of forest trees differed from each other both in characteristics of biological material cycling and in amounts of litter.The mean annual amount of litter of coniferous trees was less than 4t/ha,whereas that of broadleaf trees such as Schima wallichii and EryzhropTzloes,m,fordii was more than 6.3 t/ha.In litter coniferous trees,Ca,Mg and Si as its essential nutrient elements,made up 60-80% of total ash,these elements being usually no Hacking in soil itself,while the litter of broadleaf trees conrained considerable amounts of N,P and K in addition to Ca,Mg and Si.Each year,China fir returned to the soil 118.5 kg of ash and,nitrogen per hectare in the form of litter,Pinup massoniana 79.5 kg/ha,Schima wallichii 168.1 kg/ha,and Erythrophloeum fordii 304.8 kg/ha.