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Subtropical regions of the background conditions are chosen for this study Altingia natural forests, fir plantation, Schima superba plantation silviculture closures, tea gardens and orange grove in northern Fujian typical land use patterns as the research object, with a dry sieve method> 2mm ,2-0 .5 mm, 0.5-0 .25 m and <0.25mm 4 different size fractions of aggregates, the use of fumigation - extraction method to study the soil and aggregates microbial biomass nitrogen, phosphorus distribution characteristics to exploration of land use change on soil and its different size aggregates of microbial biomass nitrogen, phosphorus, on the regulation of this area soil nitrogen and phosphorus availability to plants is of great significance, and for the evaluation of the area of ??land quality, optimize land rational use of resources to provide the basic data. The main conclusions are as follows: 1, land use patterns have a certain impact on soil total nitrogen, total phosphorus content. Soil total nitrogen content in 0.84-5.81g/kg, different land use patterns showed: the natural forests in Altingia> Schima superba Plantation> seal silviculture> Chinese Fir Plantation> Orangery> tea plantations; conversion of natural forests to plantations , secondary forest and orchard soil total nitrogen 56.63-81.29%. Soil phosphorus content distribution 0.25-0.46g/kg overall level is low; different land use patterns showed: Orangery> Chinese Fir Plantation> fine altingia natural forest> Schima plantation> seal of silviculture> Tea Garden: conversion of natural forests Altingia fir plantations and orange grove, the increase in total soil phosphorus content, and converted into tea plantations, silviculture closure and Schima superba plantation soil phosphorus content decreased. Microbial biomass nitrogen in 23.88-103mg/kg accounted for 1.25-4.83% of the total soil nitrogen; different land use patterns showed: natural forest> plantation, secondary forest> garden: the conversion of natural forests to plantations, secondary forest and orchard microbial biomass nitrogen was significantly reduced (p <0.05). The phosphorus content of the soil microbial biomass in 10.82-16.54mg/kg 3.33-5.10% of the total soil phosphorus content, different use patterns of soil microbial biomass P, Orangery highest the tea gardens minimum, woodland performance for natural forest> plantation, secondary forest. Aggregates total nitrogen, total phosphorus content decreasing aggregate size increases, large aggregates of microbial biomass nitrogen and phosphorus content increased with aggregate size decreases. Microaggregate total nitrogen, total phosphorus content was significantly higher than the large aggregates (p <0.05), and microbial biomass nitrogen and phosphorus content in large aggregates and microaggregates difference was not significant, the reason to be further studied. 4, woodland soil total nitrogen, total phosphorus, microbial biomass nitrogen, microbial biomass P mainly> 2mm soil aggregates, fir plantation, silviculture closures, Schima superba Plantation, fine altingia natural forest> 2mm soil aggregates body in total nitrogen content accounted for 43.90-62.43% of the total soil nitrogen, total phosphorus, total soil phosphorus 49.99-57.78% 40.18-54.62% of the total soil microbial biomass nitrogen, microbial biomass nitrogen, microbial biomass phosphorus soil phosphorus 39.72 -56.63%. Tea gardens and orange grove soil total nitrogen, total phosphorus, microbial biomass nitrogen, phosphorus concentration of <2mm soil aggregates. 5 different particle aggregates content is not the same as the relationship between soil nitrogen, phosphorus content. > 2mm aggregate content and soil nitrogen, phosphorus content was a significant positive correlation (p <0.01), its content directly determine soil nutrient content. Forest soil> 2mm aggregates, conversion of forest land for the garden, with> 2mm aggregate content reduction, soil nitrogen content of a sharp decline due to the relatively large mineral release; phosphorus, the law is not obvious. 6, soil depth have a certain impact on soil total nitrogen, total phosphorus, microbial biomass nitrogen, phosphorus content, generally shows a decreasing trend with soil depth. 10-20cm soil total nitrogen, microbial biomass nitrogen, total phosphorus, the phosphorus content of the microbial biomass than the 0-10cm soil fertilization led to the Orangery. 7, microbial biomass nitrogen and total nitrogen and soil microbial biomass phosphorus and total phosphorus in the soil were highly significant positive correlation (p <0.01), microbial biomass nitrogen and microbial biomass phosphorus can be used to indicate the study area soil nitrogen, phosphorus nutrient status.
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