The Study And Application Of The Cotton Root Water Uptake Model In Drip Irrigation Under Mulched-film

Understanding the dynamic states of the cotton root water uptake and soil water content, is the important foundation of reasonable formulate irrigation regime, water-saving,ensure agriculture, high and stable yields, That is also the essential links for soil-plant-atmosphere continuum (SPAC)water moment and quantitative analysis. The research of root water uptake model began in the late 1950s and early 1960s.and into 1970s various root water uptake model were established one after another. because of the root grows in underground,that bring some inconvenience to the research work and makes slow progress. Most of water uptake models are of making the improvement to the former model, in order to consider the factors influencing the root water uptake more comprehensively and increase the simulation precision. This article through one year (2010 year) indoor barrels planted experiment and two years (2008 year and 2009 year) field experiments, reorganized the analytical investigation data in the domestic and foreign related domain rationale, initially established a suitable cotton root water uptake model in drip irrigation under mulched-film. This paper main conclusions and research results were as follows:1. In the whole growth period of cotton, the percentage of root weight has negative exponent equation relationship with vertical range and horizontal range; root length density and weight density have negative exponent relationship with vertical range too; the main root distributes in 0-50cm layers, the root length density and weight density of the wide row are more than the narrow row; the wide row is advantageous to the cotton root growth.2. The irrigation quota and irrigation cycle time have obvious influence on the number of bloom and budding of cotton, when the irrigation quota is 3300 m3/hm2and the irrigation cycle time is 8d,the bloom of cotton are the most, it is helpful for yield, but when the irrigation cycle is 10d, the bloom of cotton is the least;when the irrigation quota is 3900 m3/ hm2and the irrigation cycle time is 6d, the number of fruit branch are more; the irrigation quota is 5100m3/hm2 and the irrigation cycle time is 10d,it can make bud appear early.3. Using Feddes model established the root water uptake model. The result of its simulation value tallies well with the measured value, it can truly reflect the situation of cotton root water uptake, it indicates that the established root water uptake model is feasible.4. Through the application of model, it shows that the root water uptake model and the parameters of the model is reasonable, the model can simulation the soil water content turely; it also can simulate root water uptake in different growth period of cotton, so the model can widely be used in cotton field.