| 郁耀闯,王长燕.黄土区大豆和马铃薯田土壤临界剪切力季节动态[J].干旱地区农业研究,2018,36(1):50~55 |
| 黄土区大豆和马铃薯田土壤临界剪切力季节动态 |
| Seasonal dynamics of soil critical shear stress in soybean and potato farmlands in the loess plateau |
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| DOI：10.7606/j.issn.1000-7601.2018.01.07 |
| 中文关键词: 黄土区 土壤临界剪切力 季节动态 根系生长 |
| 英文关键词:loess areas soil critical shear stress seasonal dynamics root growth |
| 基金项目:国家自然科学基金项目(41371497，41171423，41601016)；陕西省重点实验室项目(2018JS009)；宝鸡文理学院重点科研项目(ZK2017039，ZK2017040) |
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| 中文摘要: |
| 以黄土区大豆和马铃薯田为研究对象，在6组不同水动力条件下(τ=5.71～17.18 Pa)，借助坡面径流冲刷试验，结合土壤侵蚀过程WEPP模型，探讨了黄土区大豆和马铃薯田土壤临界剪切力（τc）的季节动态变化规律。结果表明： 黄土区大豆和马铃薯田土壤临界剪切力在整个生长季表现出明显上升的季节动态变化规律（P<0.05）。大豆田τc表现为降低-升高-降低-升高-降低的季节动态模式，变化范围为1.66～5.37 Pa，平均值为3.34 Pa，最小值（1.66 Pa）出现在播种期，最大值（5.37 Pa）出现在收获期；马铃薯田τc表现为升高-降低-升高-降低-升高-降低的季节动态模式，变化范围为1.06～5.26 Pa，平均值为3.12 Pa，最小值（1.06 Pa）出现在现蕾期，最大值（5.26 Pa）出现在开花期。 两种作物田土壤临界剪切力与土壤黏结力、容重、水稳性团聚体和根重密度间呈正相关关系，其中，土壤容重和根重密度是影响土壤临界剪切力季节动态变化的重要因子。 用土壤容重和根重密度能够较好地模拟大豆和马铃薯田土壤临界剪切力的季节动态（R2＞0.50，NSE＞0.50）。 |
| 英文摘要: |
| In order to provide reference data for establishing the soil erosion process model in the loess plateau. The research take soybean and potato farmlands in the hilly region of the Loess Plateau as a target. The scouring experiments in a laboratory flume to simulate soil detachment by concentrated flow was conducted under the different condition of six flow shear stress (τ=5.71～17.18 Pa). Based on data of soil detachment capacity and flow shear stress, and combined the famous soil erosion process WEPP model, the seasonal dynamics of soil critical shear stress were discussed for soybean and potato farmlands during the crop growing season. Results showed that the seasonal dynamics of soil critical shear stress under soybean and potato farmlands in loess areas increased significantly during the whole growing season (P＜0.05). During the growing season, soil critical shear stress for soybean fluctuated over time with a pattern of double peak curve. τc values varied from 1.66 Pa to 5.37 Pa, with a mean value of 3.34 Pa. The minimum and maximum values of soil critical shear stress for soybean appeared in the seeding stage and harvesting stage, respectively. Soil critical shear stress for potato displayed similar a pattern of the seasonal variation f. τc values varied from 1.06 Pa to 5.26 Pa, with a mean value of 3.12 Pa. The minimum and maximum values of soil critical shear stress for potato occurred in the squaring stage and blooming stage, respectively. Positive relations were detected between soil critical shear stress and soil cohesion, bulk density, content of water-stable aggregates, and root weight density. Among them, soil bulk density and root weight density were important factors affecting seasonal dynamic of soil critical shear stress. Seasonal dynamics of soil critical shear stress under soybean and potato farmlands could well be simulated with soil bulk density and root weight density (R2＞0.50，NSE＞0.50). |
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