不同地表状况耕地的田面糙率研究

田面糙率是影响田面水流运动的重要参数之一.该文针对裸地、翻耕地和作物地3种不同地表状况耕地的田面糙率进行研究.分析确定了裸地和翻耕地田面糙率的主要影响因素为田面凹凸程度,作物地田面糙率的主要影响因素还包括根茎宽度和根茎高度;进行了3种地表状况的田面凹凸程度、根茎宽度和根茎高度的田间实测及田面水流运动试验;将零惯量模型与优化方法相结合,建立了田面糙率求解的优化模型;根据田面实测资料,利用优化模型求得3种耕地的田面糙率值,据此,建立了裸地、翻耕地和作物地3种耕地田面糙率与其主要影响因素之间的关系式,验证试验结果表明,所建立的关系式正确.这对合理设计田面灌溉系统,提高灌水质量具有重要参考价值.

Field roughness coefficient for different soil surface conditions

Field roughness coefficient is an important hydraulic parameter of influencing field flow movement. Field roughness coefficient for different soil surface conditions were studied The main influence factor of field roughness coefficient in bare land and plowed land was analyzed. The soil surface embossing degree, rhizome relative width and rhizome height are also main effective factors of field roughness coefficient in the crop land. Embossing degree, rhizome relative width and rhizome height in different surface conditions were measured in field, and the tests of field flow movement were done. Combination of the zero inertia model and optimization method which are established the optimization model of field roughness coefficient. Based on the measured value and the optimization model of field roughness coefficient, the calculated values of field roughness coefficient in different cultivated land were obtained. Hereby, regression equations of field roughness coefficient in bare land, plowed land and crop land were established. The equation was checked by field experimental data, the results indicated that the model was reasonable and accurate. The results are reference to design field irrigation system rationally for improving irrigation quality.