Study On Aggregates And Comenting Substance In Black Soil Under Different Tillage Methods

This paper takes the nine-year fixed field experiment black soil as research object in DeHui, To research the rotation of maize and soybeans and the composition of aggregates in Black soil, the organic carbon content of aggregates, the different bonding form of organic carbon content in soil aggregates, the composition of cementing substance in different oxidation forms of Fe and Al and the clay minerals under MP, RT and NT of continuous cultivation of corn, exploring appropriate farming methods to increase soil organic carbon content provides a scientific basis on promoting black soil carbon sequestration, improving soil quality,improving ecological environment and realizing sustainable development of agriculture.The results showed that:under three farming methods, the content of mechanical stability aggregates with diameter bigger than0.25mm is more than70%, up to93.29%, water stable aggregates content is more than20%, up to35.5%. Compared with the dry sieving method, the content of aggregates with diameter bigger than0.25mm decreased significantly. The most greatly reduced by58.76%. In two soil, rotation of maize and soybeans and the mechanical stability aggregates and water stable aggregates under continuous cultivation of corn show a certain similarity of response to tillage, ie RT> NT> MP. Organic carbon content of water stable aggregates increases with the particle size decreases, the organic carbon content under the three farming methods is NT> RT> MP, and rotation of maize and soybeans is hight than continuous cultivation of corn. RT has the most stable aggregates. Comparing the three farming methods, the ridge is more conducive to the formation of aggregates and fixed, and rotation of maize and soybeans is better than continuous cultivation of corn.In all tested samples, Ca-bound organic carbon and Fe/Al-bound organic carbon have the smallest content of organic carbon and Fe/Al-bound organic carbon has higher content of organic carbon than Ca-bound organic carbon. Various forms of iron-aluminium oxides reflect that the content is higher in top soil than bottom, Fed>Fed-Feo>Feo.All processed clay minerals have same composition, mainly consisting:Mont-morillonite, Illite, Chlorite, Vermiculite, Illite/Smectite mixed layer mineral. The main clay minerals composition under three tillage method of rotation of maize and soybeans and continuous cultivation of corn are:Illite, Illite/Smectite mixed layer mineral and Vermiculite and Illite/Smectite mixed layer mineral>Vermiculite> Illite, followed by Kaolinite and Mont-morillonite, Chlorite takes up the smallest content.Correlation coefficient analysis of various cementing substance on soil organic carbon, to the northeastern black soil we can see that there is a significant positive correlation among organic matter and free iron oxide and soil organic carbon, affecting the content of organic carbon.Correlation coefficients analysis of various types of clay minerasl content and soil organic carbon, we can see that Illite content exists a significant positive correlation to soil organic carbon content, a significant impact on soil organic carbon.