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Master of cotton root water uptake and soil water dynamics , it is reasonable to develop irrigation system , to ensure that the agricultural water-saving , stable and high yield important foundation is also a necessary part of a continuous body of water running and quantitative analysis of the soil - plant - atmosphere (SPAC ) . Root water uptake model began in the late 1950s , the early 1960s , the 1970s, various root water uptake models have appeared , because the roots grow underground and bring a lot of inconvenience to the research , progress has been slow , mostly roots the water uptake model are improvements on previous models , to make it more comprehensive to take into account the factors that affect the root water uptake to improve simulation accuracy . Barrels planted this article through the year ( 2010 ) Indoor trials and field trials in two years ( 2008 and 2009 ) , and in the related fields at home and abroad on the basis of the theory analyzed test data , suitable for cotton under drip irrigation root water uptake initially established model. The main conclusions of this paper and the results are as follows : in cotton throughout the growing period , the percentage of root weight with the vertical distance and the horizontal distance in line with the negative exponential relationship , the Cotton root length density and root weight density and the vertical distance is also in line with the negative exponential relationship , the main cotton root distribution in the 0-50cm soil layer , root weight density and root length density of cotton fields in the width of the line more than the narrow line width line is conducive to the growth of cotton root . 2 irrigation quotas and irrigation cycle of the cotton bolls, fruiting branch number and bud number also have a significant impact on cotton boll number the irrigation quota 3300 m3/hm2, irrigation cycle for 8d beneficial to cotton production , improve irrigation cycle for 10d at least the number of boll ; the irrigation quota 3900 m3/hm2 , the irrigation cycle number of fruiting branches 6d many ; the irrigation quota 5100 m3/hm2 , the irrigation cycle 10d allows cotton advance squaring . Root water uptake model Feddes model , in good agreement with the measured values ??of the simulation , the true reflection of the cotton root water uptake to establish cotton root water uptake model is feasible . Through the application of the model show that the root water uptake model and the model established by the parameter selection is reasonable to model capable of realistic simulation of soil water status , and in the cotton growing period of root water uptake analog , analog value in good agreement with the measured values ??, and can be widely used in the cotton fields .
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