Optimization And Simulation Of Cotton Irrigation Schedule For Non-film Drip Irrigation In South Xinjiang Based On Densification Mode

In order to explore a series of cultivating measures for non-film drip irrigation cotton,this paper will conduct field trials in the water conservancy irrigation test base of the First Division of Xinjiang Production and Construction Corps in 2020.The density is set to D1(240,000 plants/hm2)and D2(285,000plants/hm2).),D3(330,000 plants/hm2),three gradients of irrigation quotas I1=36 mm,I2=45 mm,and I3=54 mm.The effects of irrigation quota and seeding density on the growth and development of non-film drip irrigation cotton were carried out.Physiology and ecology,soil water and salt transport,etc.,while using the AquaCrop model to simulate the irrigation schedule and planting density,the main research results are as follows:(1)Irrigation quota and planting density will affect the growth,physiological and ecological indicators of cotton without membrane drip irrigation.When the sowing density is the same,the cotton stem thickness,plant height,leaf area and above-ground dry matter quality all increase with the increase of the irrigation quota;when the irrigation quota is the same,the cotton growth indicators are negatively correlated with the sowing density as a whole.When cotton plants are in the seedling and bud stages,the net photosynthetic rate and stomatal conductance are positively correlated with irrigation quota and negatively correlated with sowing density,while the relative chlorophyll content is the opposite.(2)Both soil moisture and salinity are greatly affected by moisture,but have little correlation with sowing density.The soil moisture content as a whole increases with the increase of irrigation quota and soil depth,and locally it is 0-20 cm and 40-60 cm soil layers.The soil moisture content is greatly affected by the irrigation cycle,but the 20-40 cm soil layer The soil water content remained basically unchanged;the soil salt content increased with the increase of soil depth within 0-60 cm,and with the change of irrigation quota,salt accumulation areas appeared in the 40-60 cm soil layer.(3)Irrigation quota and sowing density will affect the yield and quality of cotton.Yield increased with the increase of irrigation quota,and decreased with the increase of sowing density,and both reached extremely significant levels;with the increase of irrigation quota,cotton quality showed an overall upward trend,but the effect of sowing density on quality was not significant.(4)The water consumption intensity of non-film drip irrigation in different growth periods of cotton is the largest at the bud stage,reaching 3.95～5.96 mm/d,and the water consumption at the fluffing stage is the smallest,at 0.59～1.18 mm/d.The total water consumption showed an increasing trend with the increase of irrigation quota.It reached the maximum under I3 irrigation treatment,with an average total water consumption of 573.02 mm.Under I1 irrigation treatment,the average water consumption was the smallest at 399.49 mm.However,when the irrigation volume was the same,the seeding density was the same.There is no significant difference in the impact of total water consumption.(5)After the AquaCrop model parameters are calibrated,the determination coefficient R2 of biomass,yield and canopy coverage are all higher than 0.82,and the fitting index d is higher than 0.81,indicating that the AquaCrop model can simulate the southern Xinjiang region well Growth and yield of cotton without membrane drip irrigation.Based on 30 years of weather,the irrigation system of non-film drip irrigation cotton is optimized.It is concluded that the irrigation quota is 540 mm,and the cotton yield is optimal when the irrigation frequency is 5 days.The simulation of the seeding density showed that the biomass and yield showed an increasing trend but not significant with the increase of the seeding density.