Characteristics Of Soil Humus In Organic And Conventional Cultivation Mode

Currently, global warming of weather is one of the hot issues of the environment, low-carbon economic in social of development trend, organic cultivation is a model to achieve the continuous development of agriculture. The characteristics and potential of soil carbon sequestration under different cultivations was visible, they are the soil organic carbon and humus characteristics. This based organic farm located study, camparative dynamic changes in soil properties and soil humus composition in different cultivations, and further from aggregate of observe the distribution of organic carbon and humus in the soil between the various components. Study organic cultivations under different of investment product on soil humus characteristics provide the basis for the development of organic agriculture in our country.Through9years of experiment to study the soil physical and chemical characteristics of humus, the results showed that the organic cultivation of soil organic carbon, total nitrogen, available phosphorus, available potassium, soil microbial biomass carbon and enzyme activity was significantly increased; these indicators in the conventional cultivation show downtrend or of little. Results show that the9years of vegetable cultivation increased soil organic carbon (SOC) from11.41g·kg-1to15.35g·kg-1, from9.29g·kg-1to20.90g·kg-1and from9.00g·kg-1to10.00g·kg-1, humic acid carbon(CHA) from1.79g·kg-1to2.11g·kg-1, from1.23g·kg-1to3.11g·kg-1and from1.14g·kg-1to,1.31g·kg-1, and fulvic acid carbon(CFA) from2.19g·kg-1to2.44g·kg-1, from1.88g·kg-1to2.68g·kg-1and from1.73g·kg-1to1.91g·kg-1, in the organic field, organic greenhouse and conventional field, respectively. The increases in the soils under organic cultivation either in open field or in greenhouse were significant, but not so in the soil under conventional cultivation. CHA/CFA ratio and PQ value are two important indicators characterizing quality of soil humus, and were both higher in the soils under organic cultivation than in the soil under conventional cultivation. E4/E6ratio and△logK value of soil fulvic acid increased, too, in all the soils, but the increase grew more significant with age of the vegetable cultivation in the former than in the latter. Aromaticity of the soil humic acid displayed a trend of declining first and then rising, which was not so significant in the soil under conventional cultivation. All the findings indicate that long-term organic cultivation may not only be conducive to SOC accumulation, but also promote the process of soil humification.Different cultivations for soil aggregate of organic carbon and humus characteristics also different, the content of organic cultivations of soil aggregates (>2mm and2-0.25mm) higher than that of conventional cultivation, for the size of the aggregates in the organic carbon, total nitrogen content in the organic cultivation is relatively higher,>2mm and2-0.25mm size aggregates of carbon and nitrogen reserves is relatively higher. The humus components of humic acid (HA), fulvic acid (FA) in cultivation aggregates decreased with the decrease of the grain size,2-0.25mm size aggregates H/F radio, PQ values are greater than<0.25mm fraction aggregates, compared to conventional cultivation, the index higher in the soil of organic cultivation. In addition, the analysis of the optical properties of different size aggregates under different cultivations of HA, which optical density△logK value and E4/E6values are higher in the2-0.25mm tablets aggregates and the HA△logK value and the E4/E6value under organic cultivation is relatively higher, its HA molecular structure is relatively simple.Through indoor simulated test, study the influence about different organic fertilizer inputs on changes in the composition of soil organic carbon, humic acid, fulvic acid and humus in the organic cultivation. The results showed that each treatment of SOC all increased, CHE, CHA and CFA can be improved. When incubation time was prolonged, SOC decreased, fertilizer compounding is benefical to the accumulation of SOC, organic fertilizer was applied to improve the H/F and PQ value in soil, a greater increase of PQ value under fertilizer compounding treatment. Organic fertilizer treatments improve the soil HA tones coefficient and E4/E6value, its HA molecular structure show simplication.