Research of Dynamics of Soil Moisture-Thermal and Crop Water Requirement with Drip Irrigation under Mulch

Drip irrigation is the product of the combination of the world's most advanced drip irrigation and mulching planting cultivation techniques, water-saving, high yield, quality and efficiency advantages compared with traditional irrigation and cultivation techniques. Under the combined effect of the film and drip irrigation, crop growth and normal conditions, the the soil hydrothermal environment and crop water rules have changed. Cotton and corn, in Minqin small dam mouth irrigation experiment station this system field experiments, draw the following main conclusions: (1) the application of groundwater soil water flow system theory, analysis of the film under water-saving irrigation to increase production mechanism. Coating inhibits the soil surface evaporation surface sinks to mention moisture in soil moisture, drip irrigation at any time based on crop growth and crop root convergence strength increases and supplement the bus source, very highly controllable, water waste low. (2) different planting soil water the difference current system as well as water-saving increasing production efficiency difference analysis. One of three lines of soil moisture environment is better than a four-line performance in a three lines in the productivity of water, on the final yield and yield components are stronger than a four-line results. Either cultivation methods, within the scope of the maximum water supply, irrigation quota, crop production levels high. (3) mulch on the soil surface, and is not covered by soil, net radiation r_n 'income decreased sensible heat exchange P weakened, latent heat exchange LE tends to zero. The ground temperature values ??decrease with increasing depth, a sharp rise or fall of the temperature of the upper soil layer, and the lower soil smooth increment or decrease. Day Mainland temperature change characteristics can be used time 8:00,14:00,20:00 three brief characterization, representing the ground temperature minimum, maximum and intermediate temperature. Days topsoil temperature maximum amplitude and each time the maximum temperature and the maximum amplitude occurs in the film, followed by the film side, furrow. Day Mainland temperature amplitude and depth can the proposed synthetic exponential function, and have a high correlation coefficient, 0.90. (4) 2001 stress the water supply in the whole growth period of cotton evapotranspiration 307.48mm, the average daily water consumption intensity to 1.75mm, the average crop coefficient of 0.39; 2002 case of sufficient water supply in the whole growth period within the cotton evapotranspiration 337.04mm, average daily water consumption intensity of 1.94mm, the average crop coefficient was 0.43. Sufficient water supply case water demand parameters are higher than the stress of water supply. (5) integrated crop coefficient and relative moisture content of fitting the relationship between drought-hit crop coefficient and moisture content of the soil showed the same trend, the correlation coefficient of the seedling stage, and low bud stage, flowering and boll of lower to the boll opening stage was increased, the overall performance of the water in good condition, the higher the correlation. Linear fit between crop coefficient and meteorological data show that the crop coefficient with wind speed and canopy net radiation decreases with the increase of relative humidity.