Establishment and validation of wetting pattern model of moistube irrigation in homogeneous soil

doi:10.11975/j.issn.1002-6819.2020.13.010

	Establishment and validation of wetting pattern model of moistube irrigation in homogeneous soil
	Fan, Yanwei1 ; Yang, Zhiwei 1; Hu, Wulong 2
	2020-07-01
发表期刊	Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
ISSN	10026819
卷号	36 期号:13 页码:83-91
摘要	Moistube irrigation is a kind of underground line source infiltration irrigation technology developed by using the principle of polymer semi permeable membrane. The growth and yield of crops are affected by the shape and size of soil wetting pattern but the wetting pattern is not easy to observe. Therefore, it is very important to understand the shape and size of wetting pattern for the design of economic and efficient moistube irrigation system. In order to facilitate users to quickly evaluate the moistube irrigation wetting pattern, a total of 56 moistube irrigation scenarios (different combinations of eight soil textures, three soil matrix potentials and ten specific discharges of moistube) were set up. By using HYDRUS-2D software, the dynamic changes of wetting pattern under different combinations of soil saturated hydraulic conductivity, soil matrix potential and specific discharge of moistube were simulated and analyzed. The results showed that before the soil wetting front reached the surface, there was little difference in the shape of the soil wetting pattern, and its contour was almost "elliptical cylinder"; after the wetting front reached the surface, the shape of the wetting pattern at the upper part of the moistube changed from "semi ellipse" to "trapezoid", and the shape of the wetting pattern at the lower part of the moistube kept "semi ellipse". In general, soil saturated hydraulic conductivity, soil matrix potential and specific discharge of moistube had little influence on the shape of the moistube irrigation soil wetting pattern; The size of moistube irrigation soil wetting pattern at the vertical downward was larger than that at the horizontal direction and vertical upward, and with the extension of irrigation time, the wetting pattern expanded outward gradually, but the expansion rate decreased gradually. Under the condition of homogeneous soil, the contour of moistube irrigation wetting pattern was divided into two parts: the upper part and the lower part. When the upper part of the wetting boundary did not reach the surface, it could be expressed by semi elliptic equation. Under the same soil matrix potential and specific discharge of moistube conditions, with the increase of soil saturated hydraulic conductivity, at the same time, the vertical upward and horizontal migration distance of the wet front gradually decreased, while the vertical downward migration distance of the wet front first decreased and then increased; Under the same soil saturated hydraulic conductivity and specific discharge of moistube conditions, there was a positive correlation between the migration distance of the wetting front and soil matrix potential in three directions. The higher the soil matrix potential value resulted in the greater the migration distance of the wetting pattern at the same time; Under the same soil saturated hydraulic conductivity and soil matrix potential conditions, the migration distance of wetting pattern was positively correlated with specific discharge of moistube. The larger the specific discharge of moistube value could result in the faster the migration speed of wetting pattern and the larger the size of wetting pattern at the same time. Generally speaking, soil saturated hydraulic conductivity, soil matrix potential and specific discharge of moistube had significant influence on the migration of wetting pattern in moistube irrigation. On this basis, taking into the influence factors such as the total water seepage per unit length, soil saturated hydraulic conductivity, soil matrix potential and specific discharge of moistube, and based on the dimensional analysis method, the estimation model for the wetting pattern of moistube irrigation of homogeneous soil was established, and the undetermined parameters of the model were obtained quantitatively by using the numerical simulation results. Finally, the reliability of the estimation model was evaluated by the test data. The mean absolute error was not more than 2.10 cm, the root mean square error was not more than 2.46 cm, and the Nash efficiency coefficient was not less than 0.83 of statistical index of the model. It showed that the measured value was consistent with the estimated value of the model, and the model estimation effect was well. It provides a scientific basis for the operation and management of moistube irrigation engineering. © 2020, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
关键词	Hydraulic conductivity Irrigation Mean square error Mechanical variables measurement Numerical methods Seepage Soils Textures Water management Dimensional analysis methods Efficiency coefficient Irrigation engineerings Operation and management Positive correlations Root mean square errors Saturated hydraulic conductivity Semi-permeable membranes
DOI	10.11975/j.issn.1002-6819.2020.13.010
收录类别	EI
语种	中文
出版者	Chinese Society of Agricultural Engineering
EI入藏号	20203509114959
EI主题词	Wetting
EI分类号	483.1 Soils and Soil Mechanics - 632.1 Hydraulics - 821.3 Agricultural Methods - 921.6 Numerical Methods - 922.2 Mathematical Statistics - 943.2 Mechanical Variables Measurements
来源库	Compendex
分类代码	483.1 Soils and Soil Mechanics - 632.1 Hydraulics - 821.3 Agricultural Methods - 921.6 Numerical Methods - 922.2 Mathematical Statistics - 943.2 Mechanical Variables Measurements
引用统计	无
文献类型	期刊论文
条目标识符	https://ir.lut.edu.cn/handle/2XXMBERH/115264
专题	能源与动力工程学院
作者单位	1.College of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou; 730050, China; 2.School of Science, Wuhan University of Technology, Wuhan; 430070, China
第一作者单位	能源与动力工程学院
第一作者的第一单位	能源与动力工程学院
推荐引用方式 GB/T 7714	Fan, Yanwei,Yang, Zhiwei,Hu, Wulong. Establishment and validation of wetting pattern model of moistube irrigation in homogeneous soil[J]. Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering,2020,36(13):83-91.
APA	Fan, Yanwei,Yang, Zhiwei,&Hu, Wulong.(2020).Establishment and validation of wetting pattern model of moistube irrigation in homogeneous soil.Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering,36(13),83-91.
MLA	Fan, Yanwei,et al."Establishment and validation of wetting pattern model of moistube irrigation in homogeneous soil".Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering 36.13(2020):83-91.