Experiments On Soil Water-salt Distribution And Cotton Growth With Activated Brackish Water Drip Irrigation Under Plastic Mulch

In order to reveal the mechanism of increasing yield of activated brackish water,the effect of activated brackish water on cotton seedling and the effect of activated brackish water drip irrigation under plastic mulch on water and salt distribution and cotton growth characteristics were studied,which based on the physicochemical characteristics of activated brackish water.The main results are as follows:(1)The changes of the physicochemical characteristics of the activated brackish water were extremely remarkable.The surface tension coefficient reduced significantly,while the change of dissolved oxygen was opposite.The surface tension of the activated brackish water relatively reduced 9.14%～9.14%in the brackish water with salinity of 5 g/L,while the dissolved oxygen relatively increased 8.04%～10.23%.Foremost,there existed a significant index function relationship between the relative reduction of surface tension and the relative increment of dissolved oxygen.The results suggested that the surface tension relative reduction can describe the changes of the physical and chemical characteristics of the activated saline water clearly.In conclusion,the surface tension relative reduction could be used to quantitatively evaluate the changes of the physical and chemical characteristics of the activated brackish water.This study may provide valuable information for the application of activated brackish water in agriculture irrigation.(2)The activated brackish water treatment could enhance cotton seed germination potential,germination rate and germination vigor index significantly;The activated brackish water treatment could reduce the harm of high salinity on cotton in a certain extent,and improve the salt tolerance and of quality of cotton.(3)The activated brackish water irrigation treatment could improve the water retention and water holding capacity of soil effectively,and promote the absorption of cotton roots to water.The water consumption of 0-40cm root zone of cotton of activated brackish water irrigation treatment was greater than the brackish water control.Meantime,the ability of salt leaching of activated brackish water was better than brackish water,which leached more salt of the main root area of cotton into the below root zone.The salt content of 0-40cm of the main root area of activated brackish water irrigation treatment was less than that in the brackish water.(4)The activated brackish water irrigation treatment had significant effect on plant height,leaf number,leaf area index and dry matter accumulation of cotton.Compared with brackish water control,the cotton yield of activated brackish water irrigation treatment was increased by 12.41%～25.05%,and the water use efficiency was increased by 24.33%～36.36%.In addition,the stainless steel ionized activated brackish water irrigation acquired the best effect of cotton production,and the magnet of 3000Gs activated brackish water irrigation acquired the highest water use efficiency.The experimental model of cotton growth of activated brackish water could simulate the growth of cotton under different activated brackish water treatments with the growth time and the effective accumulated temperature.The chlorophyll content,maximum net photosynthetic rate and stomatal conductance of cotton under activated brackish water treatment were higher than those of brackish water treatment.The activated brackish water irrigation treatment increased the utilization efficiency of cotton to low light,and promoted the photosynthetic capacity of leaves and increased the utilization rate of light energy in cotton to a certain extent.The activated brackish water irrigation treatment could improve the water supply to cotton roots,so that the cotton leaf water potential of about 20%.