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引用本文: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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秸秆移除对西南山丘区紫色土抗侵蚀能力的影响
任涛, 贺宇欣
四川大学水利水电学院
摘要:
【目的】农业发展目前面临着可持续性的挑战,西南山丘区由于独特的紫色土及复杂多变的地形条件,大量耕地面临侵蚀的影响,水土流失造成矿物质、有机质等土壤组分从田间大量流失,严重制约了紫色土耕地的可持续发展。秸秆作为农业生产中重要的副产品,还田腐熟后能提高土壤有机质含量,为作物提供各种必需营养元素等,同时在防治土壤侵蚀方面也有显著效果,但目前西南地区大部分秸秆都没有还田,随着禁止焚烧秸秆政策的实施,大部分秸秆被随意丢弃,造成了环境污染。为研究不同秸秆移除率对西南山丘区紫色土抗侵蚀能力的影响,作者于四川省简阳市实际生产大田进行实验,选定了5个与土壤抗侵蚀能力密切相关的参数进行测量。【方法】为保证实验结果的可靠性,于实际生产大田开展实验,共设置5个不同梯度的秸秆移除率,依次为100%、75%、50%、25%、0%,并随种植时间进行冬油菜-夏玉米秸秆的移除,测定了土壤重量含水率、干容重、水稳性团聚体含量、几何平均直径、饱和导水率这5个参数,用来评判不同秸秆移除率对土壤抗侵蚀能力的影响。【结果】结果1:土壤表层0~10cm的重量含水率在不同秸秆移除率间差异性显著,25%移除率下的含水率在所有处理中最大。结果2:土壤表层0~5cm的干容重在不同秸秆移除率下均呈现出随时间逐渐减小的趋势,降幅随移除率的减小依次为5.5%、4.6%、2.1%、-5.2%、0.4%;而对于5~10cm的土层,容重的降幅依次为2.4%、5.0%、4.2%、0.8%、5.4%。结果3:25%移除率下的水稳性团聚体含量在5组处理中最大,在4次取样时依次为76.5%、81.2%、74.6%、76.8%。结果4:秸秆部分移除(移除率75%、50%、25%)能增大表层土壤的几何平均直径,土壤大颗粒团聚体数量增多,而秸秆完全移除(移除率100%)会使得表层土壤的团聚体稳定性下降,降幅随取样时间依次为31.2%、14.7%、-42.0%。结果5:移除率100%、50%、0%下的饱和导水率依次为22.5mm/min、21.3mm/min、61.1mm/min,秸秆完全不移除(移除率0%)可以促进土壤结构的改善,增加有效透水孔隙的占比,土壤入渗能力增强。【结论】秸秆移除率为25%时能显著提高紫色土耕地土壤表层的含水率,同时降低土壤容重,增大水稳性团聚体含量及团聚体平均重量直径,提高饱和导水率,土壤结构有一定的改善,土壤侵蚀退化及水土流失现象能得到缓解,土壤抗侵蚀能力增强;秸秆完全从田间移除可能会对紫色土耕地造成不良影响,加剧水土流失现象,土壤继续退化。研究成果为我国西南山丘区进行田间秸秆的部分移除提供了参考,确定了一个最佳的移除比例。
关键词:  西南山丘区;紫色土;秸秆移除;土壤侵蚀;可持续发展
DOI:
分类号:S157
基金项目:国家自然科学基金青年科学基金项目(51709190);四川省重大科技专项项目(2018SZDZX0027)
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