Comparative Study On Soil Fertility Improvement Effect Of Mechanized Straw Enrichment And Deep Returning And Other Returning Methods

Mechanized straw enrichment or innovative returning method can not only increase the content of soil organic matter and humus components,improve soil humic acid structure,but also have excellent improvement effect on soil subsurface.In this study,advanced technologies such as elemental analyzer,infrared spectrometer,thermogravimetric analyzer and fluorescence spectrum were used to comprehensively analyze the changes of crop yield,soil nutrient content,humus composition and humic acid structure in the process of returning to the field,so as to explore the influence of mechanized straw enrichment depth on soil fertilizer cultivation effect.Three groups of experiments were set up in this study: 1.The effects of non-applied straw(S-CK),straw enrichment and deep return(S-FJ),straw shallow stubble cover(S-QF),straw deep turn(S-SF)and straw mulch(S-FG)on nutrient content,humus composition and humic acid structure characteristics of chernozum soil by different returning methods were investigated.2.The effects of non-applied straw(L-CK),straw mulching(L-FG),straw overturning(L-FY)and straw enrichment and deep return(L-FJ)on nutrient content,humus composition and humic acid structure characteristics of black soil under the same straw dosage were studied.3.The effects of non-applied straw(N-CK),half straw enrichment depth(N-1/2CS),full straw enrichment depth(N-CS)and double straw enrichment depth(N-2CS)on soil nutrient content,humus composition and humic acid structure characteristics under different straw dosage were studied.The results of this study show that:(1)mechanized straw enrichment also had a better effect on increasing corn yield,and promoted the accumulation of nutrients in subsurface soil.(2)The enrichment depth of mechanized straw also significantly increased the soil organic matter content,and the enrichment depth of 10000 kg/hm2 was the best when different straw dosages were applied.After straw returning to the field,the content of dominant grain size(2-0.25 mm)aggregates was the highest,while the content of small grain size(< 0.25 mm)aggregates decreased.The organic carbon content in aggregates increased,the organic carbon content in large grain size(>0.25 mm)increased more,and the mechanized enrichment depth in soil subsurface changed significantly.(3)The carbon content of subsurface soil humus increased significantly and the degree of humus increased.The carbon content of each component of soil humus increased significantly when different times of straw were applied.(4)Deep enrichment of mechanized straw also enhanced the aliphatic property,thermal stability,oxidation degree and structure of HA molecular structure in soil.In conclusion,mechanized straw enrichment has a relatively good effect on improving soil fertility and soil humus composition.When applying different times of straw,the mechanical enrichment depth with 10000 kg/hm2 straw dosage can effectively improve soil fertilizer efficiency,which has certain significance for the implementation of green agriculture.