| ?Object?Xinjiang is a typical continental arid climate with abundant light and heat resources and large temperature difference between day and night.It is suitable for cotton growth.However,Xinjiang has a shortage of water resources.Under traditional cultivation conditions,Xinjiang cotton is mostly irrigated by flood irrigation.The water use efficiency is low,which limits the Sustainable development of cotton production.With the formation of drip irrigation cotton planting technology and large-scale promotion and application,the rapid development of cotton production in Xinjiang has been promoted.The predecessors have carried out a lot of research on the mechanism of water-saving yield increase of cotton under drip irrigation and its supporting cultivation techniques,and have clarified the mechanism of high-yield water-saving of cotton under drip irrigation,and developed a cotton cultivation technology system under drip irrigation.However,there is still a lack of research on the effects of traditional flood irrigation and drip irrigation on cotton canopy structure characteristics caused by drip irrigation under membrane and traditional flood irrigation.Based on the previous studies,this paper sets different irrigation methods and irrigation amount treatments,compares the effects of irrigation methods on cotton canopy structure and photosynthetic material productivity from the perspective of cotton canopy structure change and yield formation,and summarizes the two irrigation methods.The difference of soil moisture and its influence on cotton growth,the difference of canopy structure of cotton population under drip irrigation under film and traditional flood irrigation was discussed,and the technical way to further realize the potential of water saving and yield increase of cotton under drip irrigation was discussed.?Methods?Two irrigation methods were set up in the experiment:Drip irrigation and traditional flood irrigation,and two irrigation treatments:3900 m3·hm-2 and 6000 m3·hm-2,for a total of 4 treatments(FI-3:The amount of drip irrigation under the membrane is traditionally flooded,the water volume is 3900 m3·hm-2;FI-6:traditional flood irrigation,water volume 6000 m3·hm-2;DI-3:drip irrigation under the membrane,water volume 3900 m3·hm-2;DI-6:The traditional flood irrigation amount is subjected to drip irrigation under the film,and the water volume is 6000 m3·hm-2).The effects of different irrigation methods on cotton canopy structure and population photosynthetic productivity were investigated by measuring plant height,leaf area index,light absorption rate,population photosynthetic productivity,biomass and yield composition.?Results?The results showed that:?1?The soil moisture of cotton under drip irrigation was mainly concentrated in 0-60 cm soil layer,and the water change was stable with small fluctuation;the soil layer below 60 cm,with the increase of soil depth,the response of soil water content to irrigation decreased gradually.The traditional flood irrigation cotton has large fluctuations in 0-100 cm soil layer,and the soil water content of 80-100 cm soil layer has obvious response to irrigation water,and the water supply is unstable,which affects cotton growth and development.Studies have shown that the sensitivity of cotton plant height to the response of the two irrigation methods is quite different.With the increase of irrigation amount,the traditional flood irrigation cotton plants increased by 6.68 cm and 6.10 cm respectively in the 2years,while the drip irrigation cotton only increased by 1.74 cm and 0.7 cm;the change of the number of main stems and the number of branches of cotton was the same as the change of plant height.After the irrigation of the cotton under the film increased to 6000 m3·hm-2,the number of main stems and the number of fruit branches did not increase significantly.However,the number of main stems and the number of fruit branches in traditional flood irrigation cotton increased significantly.?2?With the increase of irrigation amount,the irrigation water use efficiency showed a decreasing trend.The utilization efficiency of cotton irrigation water treated with 3900 m3·hm-2 under drip irrigation was significantly higher than other treatments;the plant leafbell configuration was reasonable in the middle and late growth stages of cotton,and the photosynthetic productivity of the population was high.High,which is conducive to the transport and accumulation of photosynthetic products to product organs,which is conducive to the formation of yield,and the single boll weight is large.The yield of cotton seed cotton was the highest in 3900 m3·hm-2treated with submerged drip irrigation in 2 years.The traditional cotton irrigation with 6000 m3·hm-2 was the second.The excessive irrigation of cotton under drip irrigation was not conducive to the formation of yield,while the traditional flood irrigation increased yield,Significant.?3?In the late stage of Shengling,the upper leaf area index of cotton treated with 3900 m3·hm-2 under drip irrigation was maintained between2 and 2.5,and the middle and lower parts were between 1 and 1.5.Meanwhile,the upper transmittance was good,middle and lower.The light absorption is increased,the leaf area is evenly distributed vertically,and the leaf bells are arranged properly,which is beneficial to the production of photosynthetic products.Under the same flooding conditions,under the condition of traditional flood irrigation,the cotton is drought-stricken,and the leaves of the plant are seriously detached.Although the upper part has good light transmission,the middle and lower leaves are insufficient in area,the intercepted light energy is small,the photosynthetic production is insufficient,and the yield is low.With the increase of irrigation amount,the soil water content increased rapidly,the upper leaves of the canopy increased,the leaf area index of the whole plant increased significantly,and the lower light loss improved.However,the situation of the sharp decline of the central leaves in the late growth stage still did not change.The leaf bell configuration and the light energy distribution ratio are not well matched,and the population photosynthetic productivity is insufficient.There is still a big gap compared with the 3900 m3·hm-22 treated cotton yield under the membrane drip irrigation.?Conclusion?Compared with traditional flood irrigation,the drip irrigation under the membrane has less fluctuation of soil moisture,and the water supplied to the cotton plant is relatively stable.It can shape the dominant plant type with suitable plant height,multiple fruit branches and multi-main stem segments,and is an excellent canopy structure in the late growth stage.Foundation.At the beginning of the Shengling period,the leaf area index of the traditional flood irrigation cotton was low,the light interception was less,the photosynthetic productivity was weak,and the number of bolls per plant and single boll weight were insufficient,resulting in less dry matter accumulation and low yield;under-film drip irrigation There is sufficient leaf area in the upper part of the cotton,the overall light energy absorption is strong,the light loss in the middle and lower parts is small,the photosynthetic productivity is strong,and the bells are evenly distributed in each layer,which lays a foundation for the formation of yield.The irrigation amount increased to 6000 m3·hm-2,the vegetative growth time of cotton under drip irrigation was prolonged,the accumulation time of photosynthetic products to reproductive organs was insufficient,the proportion of green bells in harvesting was still high,and the yield decreased;the area of upper and lower leaves of traditional flood irrigation increased.The light interception ability is improved,the group photosynthetic capacity is improved,the upper bell ringing ratio is increased,and the yield increase is remarkable.Suitable for drip irrigation under film,easy to shape better canopy structure,is conducive to group photosynthetic production;Shengling period,reasonable source-storage ratio,number of bolls per plant,single bell,large accumulation rate of photosynthetic products,beneficial to cotton high yield.Therefore,Xinjiang cotton area should further increase the yield,while ensuring stable ringing in the middle and lower parts,increase the amount of ringing in the upper part of the cotton plant canopy,and retain the appropriate leaf area. |
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