| Water shortage has become an important factor restricting global crop production and agricultural development.Rational irrigation technology is the key measure to promote crop growth and increase yield.Inadequate irrigation is one of the effective ways to improve water use efficiency and develop water-saving agriculture.In this paper,Xinluzhong 54 was used as a test variety to conduct field split plot experiment in Awati County,Xinjiang.The main plot was drip irrigation cycle 7 days/time(T1),10 days/time(T2),and the sub-plot was 3 drip irrigation frequencies 6 times(D6),7 times(D7),8 times(D8).The effects of insufficient drip irrigation on water use and yield formation of 76 cm cotton with equal row spacing were studied.The main results are as follows:1.Effect of insufficient drip irrigation on water use of 76 cm cotton with equal row spacingUnder inadequate drip irrigation,the treatment of T2(once every 10 days)during different drip irrigation cycles increases soil moisture content in different depths of the key growth period(flowering and boll stage)of cotton,resulting in an increase in average daily water consumption,water consumption and total water consumption of cotton in each growth period,thereby increasing water use efficiency of cotton leaves,population biomass,seed cotton yield,water use efficiency and irrigation.Water use efficiency.During different drip irrigation frequencies,D7(7 times)treatment maintained higher soil moisture content in cotton fields during the critical growth period(flowering and boll stage)and different soil depth(0-60 cm),and increased the average daily water consumption,water consumption and total water consumption of cotton at different growth stages.Thus,the water use efficiency of cotton leaves,total water consumption of cotton,seed cotton yield,population biomass,water use efficiency of cotton plants,water use efficiency of water consumption and irrigation water use efficiency were improved.2.Effects of insufficient drip irrigation on photosynthetic characteristics of 76 cm cotton with equal row spacingUnder inadequate drip irrigation,the treatment of T2(once every 10 days)increased LAI,canopy opening DIFN,chlorophyll a,b,a+b content,chemical maximum rate(Fo/Fv),photochemistry quenching coefficient(qP),photochemistry quantum yield(Yield),intercellular CO2 concentration(Ci)and net photosynthetic rate(Pn)of cotton during flowering and boll stage,and decreased non-photochemistry quenching coefficient(qN).During different drip irrigation frequencies,LAI,canopy opening DIFN,chlorophyll a,b,a+b content,photochemical maximum rate(Fo/Fv),photochemical quenching coefficient(qP),photochemical quantum yield(Yield),stomatal conductance(Gs),intercellular CO2 concentration(Ci)and net photosynthetic rate(Pn)of cotton increased first and then decreased with the increase of drip irrigation frequencies.The drip irrigation frequencies of D7(7)were higher than those of other treatments.The,transpiration rate(Tr)and non-photochemical quenching coefficient(qN)of cotton were significantly lower than those of other treatments.3.Effect of inadequate drip irrigation on cotton yield with 76 cm equilateral spacingUnder inadequate drip irrigation,the treatment of T1(once every 7 days)during different drip irrigation cycles increased cotton plant height,internode length of main stem,width of top four leaves and number of buds.However,the treatment of T2(once every 10 days)in drip irrigation cycle increased the number of cotton leaves,the proportion of peaches and autumn peaches.It also prolonged the period of rapid growth of vegetative organs and total dry matter accumulation on the ground and at the end of the period of rapid growth,resulting in the accumulation and growth of vegetative organs,reproductive organs and total dry matter,thereby increasing the accumulation and distribution of reproductive organs(buds,boll hulls,fibers),and eventually increased lint yield by 82.86-252.23 kg·hm-2 on average.In different drip irrigation frequencies,plant height and the width of the top four leaves decreased with the increase of drip irrigation frequencies.The number of buds,bolls,the proportion of peaches,the total amount of dry matter accumulation in reproductive organs and shoots of cotton plants,the number of bolls per plant,the yield of seed cotton and lint increased first and then decreased.D7(7)treatment was superior to other treatments.In summary,in Aksu region of southern Xinjiang,when the period of drip irrigation under inadequate drip irrigation is T2(10 days once)and the frequency of drip irrigation is D7(7 times),the soil moisture content is higher,the water consumption is more uniform,the water utilization rate is higher,the canopy structure is reasonable,the photosynthesis performance is stronger,the accumulation of dry matter is more,and the proportion of distribution in reproductive organs and nutrient organs is balanced.High yield can be obtained. |
