| Drip irrigation technology is widely used in the cultivation and production of cotton,corn,wheat and other field crops in Xinjiang.This drip irrigation technology has many advantages such as saving water and labor,increasing production.It played an important role in wheat production and yield increase in northern Xinjiang.However,there are still some problems of drip irrigation in terms of the large drip water amount,high irrigation frequency,drip tape configuration,and so on.Research in related fields is still in the preliminary stage.As a result,the potential for water saving,production increase,and efficiency enhancement of drip irrigation technology in wheat cultivation have not been fully exploited.This research was focusing on the efficiency of drip irrigation of winter wheat based on yield and profit.In field conditions,we chose one drip belt for four rows of wheat.Study on distribution characteristics of soil water diffusion and use in different drip irrigation winter wheat;Differences in canopy traits,photosynthetic characteristics and yield formation of winter wheat with different drip irrigation amounts;Study on effect of drip irrigation coupling on yield formation and water use efficiency of winter wheat in key periods.The aims were to provide theoretical basis and technical support for high yield and efficiency,rationalization of water supply for winter wheat in Xinjiang by drip irrigation.The main results were as follows:1.The spatial and temporal variation of soil moisture in winter wheat and agronomic character of different wheat rows under different irrigation levelsThe soil moisture increased with the increasingdrip amount under the same soil layer.The water content close to drip beltwas higher than that at long distance which is the middle place between two drip belts,and the difference became more obvious with decreasing irrigation amount.When the drip amounts less than 3750 m3·hm-2,water cannot spread to middle place between two drip belts,and vertically did not reach the 60 cm soil layer,making wheat in drought stress affecting its development.In the vertical direction,soil moisture increased with increasing soil depth,dramatically changed at 0?40 cm soil layer.6 hours after dripping with 3750 m3·hm-2,the water diffused to the 0?60cm soil layer and horizontally to45 cmbetween two drip belts.The soil moisture difference was mainlyin 0?80 cm soil layer,little difference in 80?200 cm soil layer,and water was mostly in 20?80 cm.Following theincreasing time,the soil moisture was generally decreased.Length,leaf,and area of leafdecreased with the decreasing leaf position.Under the identical irrigation amount,length,width,and area of leaf near the drip belt were higher than that at long distance,as well as length of internode,stalk coarse,stem diameter,dry matter accumulation of various organs.Furthermore,this trend was more notably following decreasing irrigation amount,and increased with increasing irrigation amount for the same line of wheat.The height of winter wheat was 71.19?85.09cm in all the treatments.Ear length varied consistently following with the variation of plant height,with the order:wheat line near the drip belt in high water treatment>wheat line near the drip belt in medium water treatment>wheat line long distance apart from the drip belt in high water treatment>wheat line near the drip belt in low water treatment>wheat line long distance apart from the drip belt in medium water treatment>wheat line long distance apart from the drip belt in low water treatment.Length of wheat intemode decreased following the decreasing internode level.The wheat stem diameter changed from 0.133 cm to 0.210cm in the treatments,which became thinner following the decreasing segment.The top third section was the thickest,which in the treatments followed the order:high water treatment>medium water treatment>low water treatment;wheat line near the drip belts>wheat line long distance apart from the drip belt.Significant differences in leaf area,plant height and panicle length between different wheat rows(p<0.05).2.Photosynthetic product and grouting features of different wheat rows under different irrigation levelsThe change of SPAD values at different growth stages was consistent in different treatments,which in wheat row far from the belt was higher than that near the drip belt before flowering.This trend became opposed after flowering.The SPAD values dropped following the decreasing leaf position.After the flowering period of a small amount of irrigation,the SPAD value of the long-distance wheat rows declined fastest.Net photosynthetic rate(Pn),transpiration rate(Tr)and stomatal conductance(Gs)were the highest at flowering,that of the wheat row near the beltwas greater than the wheat line far from the belt.At the same location,Pn and Trincreased with the increasing drip irrigation amount.Water use efficiency of leaf(WUEL)decreased following the development,which was the maximum at jointing.The change of limiting value of stomata(Ls)following the order:flowering>jointing>filling,the wheat line far from the drip belt>the wheat line near the drip belt,high water treatment>medium water treatment>low water treatment.The decreased irrigation shortened grain filling duration,Low water treatment reduces grouting time by 3 to 4 days compared with medium and high water treatment.With no different among the treatments,while the grouting rate peaked 20?25 d after flowering in high water treatment and medium water treatments.The average grain weight of the wheat line long distance from the belt was 2.55 g/1000 grain and 2.59 g/1000grain in higher and medium water treatments,respectively,and the grouting rate in low water treatment peaked 15?20 d after the flowering,and the average grain weight was 2.48 g/1000grain.The distance between the beginning and the end of the grouting of the wheat line near the tube line was earlier.Following the decrease of drip amount,soil water consumption increased.Furthermore,soil water consumption of the wheat line long distance from the drip belt was higher than that near the belt.At the same location,the total water consumption increased with the increasing drip amount.3.Effects of different drip amounts on the yield formation of winter wheat and the characteristics of water consumptionWith the increasing drip amount,the Pn,Tr and Gs of winter wheat leaves presented the trend of"increasing first and then decreasing",and the W5 treatment had the maximum value.The Ci decreased with the increase of drip irrigation amount.The dry matter of single plant in the treatments varied following an "S" type curve.The maximum growth rate(Vm)of dry matter was "increasing first and then decreasing",increased with the increasing drip amount with the maximum of 0.072 g plant-1·d-1(W5).The appeared time of Vm(tm)in W5 was the earliest,while the fast growing time(?t)was shorter than the other treatments by 0.3 d to 4.62 d.The grain yield and WUE of winter wheat also had the trend of"increasing first and then decreasing".The yield of W5 was the highest,9039.93 kg·hm-2,significantly different with other treatments(p<0.05).WUE of W4 was the highest.1.29 kg.m3 at W4,no significantly different compared with W3 and W5.With the increasing drip amount,the soil water consumption decreased gradually.The IWUE in the treatments declined following increased drip amount,which was the highest in WO treatment with 4.53 kg.m3,and decreased with an average of 0.53 kg.m3,when increasing the same amount of water.Compared with W7 treatment,the LAI,dry matter accumulation,photosynthetic parameters and yield,WUE and IWUE of the CK were lower.4.Effects of water management at jointing and flowering stages on growth,development and yield of winter wheatThe total irrigation is 4 500 m3·hm-2,and ppropriately increase joint irrigation(During jointing:1350 m3·hm-2-1 500 m3·hm-2)and during flowering(1 200 m3·hm-2-1 350 m3·hm-2),,in other periods(450m3·hm-2·per time,6 times).Our results found two optimized irrigation modes for winter wheat of Xinjiang:(1)on the basis of 600 m3·hm-2,the wheat resistance to the reverse can be enhanced by the mode that 1 350 m3·hm-2at jointing and flowering,respectively,plus six time irrigation with each of 450 m3·hm-2at the other stages,saving 750-1 800 m3·hm-2(15%?20%)and 2?4 irrigation times compared with CK,as well reducing the labor input and increasing the product efficiency and WUE;(2)on the basis of 600 m3·hm-2,the water storage at early growth can be enhanced by the mode that 1 350 m3·hm-2at jointing and flowering,respectively plus six time irrigation with each of 450m3·hm-2at the other stages,as well with the optimized SPAD of wheat group,WUE and WUEL,and the increased the biological yield and economical yield,which can save 1 800 m3·hm-2(20%),and 2?4 irrigation times compared with CK,as well reducing the labor input and increasing the product efficiency and WUE. |
PDF Full Text Request