Effects Of Tillage Methods On Structural Stability Of Red Soil In Slope Farmland

Sloping farmland is an important soil resource for dry land grain,economic crops and fruit tree production in Guangdong Province.Soil erosion in sloping farmland in southern latosolic red soil is one of the important environmental problems facing China.It is a suitable farming method suitable for the region.To explore the suitable tillage method for this area is important measures for solve the sustainable agriculture and environmental resource issues of slope farmland.In this study,the latosolic red soil of the experimental land after five different tillage treatments in Slope Farmland of Zhanjiang City,Guangdong Province was selected as the research object.The research objectives are: 1)the effects of different tillage methods on soil structure water stability and mechanical stability;2)the effects of tillage methods on soil pore structure,water holding capacity and nutrient content;3)Relationship between soil structure water stability and mechanical stability and soil properties,in order to gain a deeper understanding of the impact mechanism of soil structure stability under different tillage treatments.The main results and progress of the study are as follows:1.Compared with the traditional tillage,the implementation of no-tillage treatment is conducive to the improvement of soil nutrient content in the surface layer and the bottom layer.It also conducive to improving soil acidification and sandfication,promoting the loosening of the bottom soil and improving the water holding capacity,and improving soil nutrient.It is the appropriate tillage treatments for the soil nutrient content.The study found that deep-tillage and conventional+subsoiling-tillage treatment can promote the mixing of soil organic matter in the surface layer(0-10 cm),the underlying layer(10-20 cm)and the bottom layer(20-30 cm),and improve the soil pore structure.And water holding capacity,but will reduce the nutrient content of the middle and upper layers of soil.The effect of compaction on soil compaction and pore structure has not been reflected in the short term.2.The frequency,intensity and range of soil disturbance caused by different tillage methods are different,and the effect on soil aggregate water stability is also different.The implementation of no-tillage treatment can improve the water stability of soil aggregates,reduce the breakage rate of large aggregates,and facilitate the preservation of aggregates of organic carbon in the surface layer of soil.The effects of deep-tillage and conventional+subsoiling-tillage on the water stability of soil aggregates were mainly concentrated in the middle and upper layers,which increased the organic carbon content of the large macroaggregates,but reduced the organic carbon content of the microaggregates.Compaction has the strongest effect on the fracture of macroaggregates in soil,which is not conducive to the water stability of soil aggregates.Among them,microaggregate organic carbon is the main way of soil organic carbon sequestration.The increase of Soil total organic carbon,dissolved organic carbon(DOC),hot water extraction organic carbon(HWOC),>2mm particle size and 0.25-2 mm particle size can significantly improve soil cementation.And the stability of soil aggregates is significantly improved.3.Deep-tillage and conventional+subsoiling-tillage mainly reduce the mechanism of soil structure stability by reducing the soil bulk density and reduce the soil tillage resistance.No-tillage is less loosening of the soil so the tensile strength and penetration strength of the topsoil are higher than that of tillage.With the extension of tillage time,the penetration resistance of the no-tillage soil is gradually lower than that of tillage.Compaction increases the tensile strength of the soil's surface and underlying layers.Soil porosity,clay content and bulk density are important influence factors affecting the mechanism of soil structure stability.4.Water repellency of soil aggregates was not found from each tillage treatment.Compaction reduces the sorpotivity and water repellerncy of soil aggregates in various soil layers.The increase of tillage depth and subsoiling-tillage can reduce the water repellerncy of the bottom soil aggregates.The hot water extraction organic carbon(HWOC)is the main factor affecting the water repellency of soil.The porosity and sand content of soil aggregates can be characterized and explain the sorption of soil aggregates.here is a positive correlation between water repellency and water stability of soil aggregates.It shows that improving the water repellency of soil can effectively improve soil water erosion resistance.