Studies On The Changes Characteristic Of Black Soil Organic Carbon Fractions With Different Forms In Heilongjiang Province

Generally believing, increasing the content of soil organic matter can effectively improve the soil chemicophysical properties. However, correlations between black soil organic carbon fractions themselves and theirs with variable links to soil chemicophysical properties have not be well understood. In this paper, the measurement index of TOC and three labile carbon soil microbial biomass carbon(SMBC),water soluble organic carbon(WSOC),Potentially Mineralisable carbon which can better reflect change of soil characteristics were selected, in order that people can better understanding the variation characteristics and its ecological significance soil of black soil organic carbon fractions in cold. Explore soil total carbon sensitive indicator factor is of significance to evaluation soil organic carbon and soil fertility. Aim of this study is to investigate relationships of soil organic carbon fractions and their soil physical, chemical properties in four black soil regions of Heilongjiang Province: Nenjiang, Hailun, Suihua, shuangcheng.The result shows that Nenjiang's water content and field capacity is the highest, Shuangcheng is the lowest, Nenjiang> Hailun> Suihua> Shuangcheng by comparing, on the whole, the supply and preserve water capacity has an increasing trend from south to north. Shuangchang's bulk density is the highest, Nenjiang is the lowest,Nenjiang< Hailun< Suihua< Shuangcheng by comparing. Soil of black soil region is more compact , the soil structure deterioration is more serious from north to south in Heilongjiang Province. Analysising of soil cation exchange capacity shows that capacity of applying and conservating fertilize has an increasing trend from Shuangcheng to Suihua to Hailun.The average content of the soil microbial biomass carbon is Nenjiang> Hailun> Suihua>Shuangcheng, Nenjiang, Hailun, Suihua higher than Shuangcheng 15.89%, 49.16% and 55.13% respectively. According to differences in soil microbial biomass carbon content, The black soil of Nen River is significant difference from the three region, but few differences between Hailun, Suihua and Shuangcheng. From segmental analysis, we can know that the largest proportion of maximum content >400.00 mg/kg is Nenjiang, the smallest proportion is Shuangcheng,in the minimum content 100.00-200.00 mg/kg, highest proportion is Shuangcheng, it has an rising trend on the whole from south to north. From analysis of water soluble organic carbon, we can know that it has an increasing trend from Shuangcheng to Hailun. Soil mineralisable's dynamic changes carbon is significantly different in the cultivation process by region; The variation trend of Hailun and Suihua is similar,the average daily amount of mineralized carbon is lower at prior period, peak value arises in middle period. The average daily amount of mineralized carbon in Chuangcheng changes smoothly at prior period, the variation trend is similar with Hailun and Suihua at middle period and later period. The average daily amount of mineralized carbon in Neijiang is higher, peak value arises between 3-9 days, after that, decline rapidly, As the cultivation time extending, the average daily amount of mineralized carbon arises peak value again between 33-36 days,after that, decreasing. Through analysis with the accumulative amount of mineralized carbon, we can know that Hailun> Nenjiang> Suihua> Shuangcheng for comparing the average content, it has an rising trend on the whole from south to north.Black soil organic carbon content, organic carbon fractions content and total nitrogen content with latitude all present positive correlation, it shows that hydrothermal conditions not only determine the organic carbon and spatial distribution of nitrogen, but also determine spatial distribution of organic carbon fractions. Correlation of soil organic carbon fractions and soil total carbon is obvious. Soil microbial biomass carbon, water soluble organic carbon, accumulative mineralized carbon present positive correlation obviously each other. Soil total carbon and fractions themselves with bulk density all present negative correlation ,but with water content, field capacity all present positive correlation obviously, soil total carbon and fractions themselves with CEC all present positive correlation, it shows that soil total carbon and fractions is bound up with the soil chemicophysical properties.