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The Soil Infiltration Law Of Film Slit Furrow Irrigation And Numerical Simulation

Posted on:2008-02-20Degree:MasterType:Thesis
Country:ChinaCandidate:Y XueFull Text:PDF
GTID:2143360215994451Subject:Agricultural Soil and Water Engineering
Abstract/Summary:PDF Full Text Request
For the plastic mulching irrigation, there are two main kinds, which are the irrigating water on the plastic film and the irrigating water under the plastic film. For the plastic mulching irrigation methods have definite characteristic and special application condition, so the different irrigation methods should be selected according to the factual situation for different areas. So far, the most popular irrigation technique in practice are it mainly includes irrigation technique of film slit, irrigation technique of film hole, irrigation technique of sprinkler irrigation on the film, and irrigation technique of sprinkler irrigation under the film.Based on the theory and technique research home and abroad, and combined with the characteristic of film slit furrow irrigation, this article researched the infiltration characteristic of film slit furrow irrigation, obtained the infiltration parameters, modified the present infiltration model, and then soil water moving characteristic of film slit furrow irrigation was numerical simulated to optimize the group of the irrigation technique factors, which offered important theoretical evidence for the further research of infiltration of film slit furrow irrigation, moving laws of surface flow, optimization of irrigation factors and systemic management and design.1,Based on the infiltration experiment of film slit furrow irrigation, the influence of the factors of film slit width, soil initial moisture percentage, bulk density of soil and the water depth of the soil box on the factors of accumulative total infiltration capacity, infiltration velocity, the propelling distance of vertical and horizontal wetting front and their ratio were researched. The research showed that the larger the film slit width was, the less accumulative total infiltration capacity and infiltration velocity were, and the more propelling distance of vertical and horizontal wetting front horizontal and their ratio were in the same infiltration time when the other factors were the same;The higher the soil initial moisture percentage was, the less accumulative total infiltration capacity and infiltration velocity were, and the less propelling distance of vertical and horizontal wetting front horizontal and their ratio were;The influence of the bulk density of soil and the water depth of the soil box on infiltration was far less than film slit width and soil initial moisture percentage on infiltration.2,According to the infiltration data of film slit furrow irrigation, A.H.KOCTŠÆKOB infiltration model was modified. And the infiltration models were established using the parameters of film slit width and soil initial moisture percentage respectively. Moreover, the mathematical model of the propelling distance of vertical and horizontal wetting front varying with time was perfected.3,The movement of water infiltration function was solved and numerical simulated by adopting ADI combined with the initial and boundary condition based on the principle of soil water dynamics. By making comparison of the numerical simulated results and the experiment results, it was known that the experiment was reasonable with certain accuracy.4,Based on the above research and the orthogonal experiment data, by adopting the range analysis method, the most excellent technique elemental combination were got to use the assessment indicators of accumulative total infiltration capacity, infiltration velocity, and the ratio of propelling distance of horizontal and vertical wetting front, which has certain theoretical and practical meanings in improving the utilization ration of field water and irrigation water.
Keywords/Search Tags:film slit furrow irrigation, infiltration characteristic, technique elemental factor combination, tow-dimensional infiltration, mathematical model
PDF Full Text Request
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