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Cite this article:任涛,贺宇欣.秸秆移除对西南山丘区紫色土抗侵蚀能力的影响[J].灌溉排水学报,0,():-.
rentao,heyuxin.秸秆移除对西南山丘区紫色土抗侵蚀能力的影响[J].灌溉排水学报,0,():-.
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DOI:
Effects of Straw Removal on Erosion Resistance of Purple Soil in Hilly Areas of Southwest China
rentao, heyuxin
College of Water Resources and Hydropower Engineering, Sichuan University
Abstract:
【Objective】At present, agricultural development is facing the challenge of sustainability. Due to the unique purple soil and complex and changeable terrain conditions in the hilly areas of southwest China, many cultivated lands are affected by erosion. Soil and water loss cause a large loss of soil components such as minerals and organic matter from the field which seriously restricts the sustainable development of purple soil. As an important by-product in agricultural production, straw can improve the content of soil organic matter after returning to the field and being decomposed, providing various essential nutrients for crops, and also has a significant effect in preventing soil erosion. In order to study the effects of different straw removal rates on the erosion resistance of purple soil in hilly areas of southwest China, the author conducted experiments in actual production fields in Jianyang, Sichuan province, and selected 5 parameters closely related to soil erosion resistance for measurement.【Method】In order to guarantee the reliability of the results, in the actual production field to carry out the experiments, were set up five different gradient of straw removal rate, followed by 100%, 75%, 50%, 25%, 0%, and with the planting time for winter rapeseed - summer maize straw to remove, determine the weight of soil moisture content, dry density, water stability aggregate content, geometric mean diameter, saturated hydraulic conductivity of the five parameters, used to judge the different straw removal rate of soil erosion resistance.【Result】Results 1: the water content of soil surface 0 ~ 10cm by weight had a significant difference among different straw removal rates, and the water content under 25% removal rate was the largest among all treatments. Results 2: the dry bulk density of soil surface 0 ~ 5cm showed a trend of decreasing gradually with time under different removal rates, and the decrease with the removal rate was 5.5%, 4.6%, 2.1%, 5.2% and 0.4%, respectively. For the soil layer of 5 ~ 10 cm, the bulk density decreased by 2.4%, 5.0%, 4.2%, 0.8% and 5.4% respectively. Results: the content of water-stable aggregates under the 3:25% removal rate was the largest among the five groups, which was 76.5%, 81.2%, 74.6% and 76.8% respectively at the 4 sampling times. Results 4: partial removal of straw (removal rate of 75%, 50% and 25%) can increase the geometric average diameter of topsoil and increase the number of soil large-particle aggregates, while complete removal of straw (removal rate of 100%) can decrease the stability of topsoil aggregates by 31.2%, 14.7% and -42.0% respectively with sampling time. Results 5: Under the removal rates of 100%, 50%, and 0%, the saturated water conductivity was 22.5mm/min, 21.3mm/min, and 61.1mm/min, respectively. Complete removal of straw (removal rate of 0%) could promote the improvement of soil structure, increase the proportion of effective permeable pores, and enhance soil infiltration capacity.【Conclusion】 Straw removal rate was 25% when the moisture content of the soil surface can significantly improve the purple soil, reduce soil bulk density at the same time, increasing the water stability of aggregate content and aggregate diameter, average weight increase saturated hydraulic conductivity, soil structure has a certain improvement, degradation of soil erosion and water loss and soil erosion phenomenon can be alleviated, soil erosion resistance ability; The complete removal of straw from the field may have a negative impact on purple soil, aggravating soil erosion and soil degradation. The research results provide a reference for the partial removal of straws in the hilly area of southwest China and determine an optimal removal ratio.
Key words:  Southwest hilly area; Purple soil; Straw removal; Soil erosion; Sustainable development