Effects Of Different Water And Nitrogen Treatments On Dry Matter Production And Water Consumption Characteristics And Yield Of Winter Wheat

In order to study the key cultivation techniques of high yield and good qualitywith water-saving and nitrogen-saving, three irrigation levels and five nitrogen levelswere set up to synthetically research the effects of different irrigation and nitrogentreatments on dry matter production and water consumption characteristics and yieldin winter wheat under field conductions across two consecutive years2010-2012.Three treatments of irrigation (W0, no irrigation; W1, irrigation once at jointing stage;W2, irrigation twice at jointing and anthesis stages) with irrigation amount75mmeach time, and five N fertilizer rate (0kg hm-2, N0;90kg hm-2, N1;180kg hm-2, N2;240kg hm-2, N3;300kg hm-2, N4) were designed with winter wheatBainongaikang58. The main results were as follows:1. Effects of different irrigation and nitrogen treatments on dry matterproduction and transportation of winter wheatDynamic changes of the dry matter accumulation in different treatments took onthe treads of slow-fast–slow pattern with the of growth development with reachingpeak at mature period. The period of jointing to anthesis was the vigorous growthstage, and the growth rates of dry matter were the fastest. The dry matteraccumulation increased with the increase of irrigation frequency, while the trendswere different with the increase of N application rate due to the different precipitationduring growth period in wheat. The precipitation was less in2010-2011during thegrowth season of wheat, and more in2011-2012. The dry matter of vegetative organscontribution amount and its contribution rate to grain before flowering in N2treatments were the highest under W0and W1in2010-2011, while the dry matter ofvegetative organs contribution amount after flowering in N3treatments was thehighest under the same conditions. The differences of dry matter amount between thetreatments of N3and N4was not significant in2011-2012, while the dry matter ofvegetative organs contribution amount and its contribution rate to grain beforeflowering in N3treatments were the highest in2011-2012. Irrigation two times in2010-2011and one time in2011-2012can increase the contribution rate of the drymatter to grain after flowering.2. Effects of different irrigation and nitrogen treatments on plant nitrogenaccumulation and transportation and utilization of winter wheatThe nitrogen accumulation of plant increased with the wheat growing, and theapplied nitrogen treatment was significantly higher than that of N0treatment. Thenitrogen accumulation amount were higher for plant in N3and for grain in N4atmature period, and the irrigation treatments is significantly higher than no irrigation. The N Transport of vegetative organs and its contribution rate to grain after floweringwas different due to water condition changes. The treatment of N4was relativelyhigher under water deficiency such as W0and W1of2010-2011and W0of2011-2012.The treatment of N3was higher under enough moisture such as W2in2010-2011and W1and W2in2011-2012. The nitrogen fertilizer productionefficiency decreased with N application increasing. The nitrogen absorption efficiencywas strongly influenced by irrigation conditions and decreased with the increasingapplication rate of N under the condition of no irrigation, and increasing at first andthen reducing under the condition of irrigation.3. The effects of different irrigation and nitrogen treatments on waterconsumption characteristics of winter wheatThe evaporation were the highest from jointing to anthesis in2010-2011and fromwinter to jointing was the highest in2011-2012due to the impact of differentirrigation and precipitation. The daily average of evaporation from jointing tomaturity was relatively higher in two consecutive years. Evaporation increased withthe increase of irrigation times, and decreased with nitrogen fertilization increasing.Compared with N0,the cumulative evaporation of applied nitrogen treatments decreasedfor N3by24%and for N4by29%to32%in two years. The total waterconsumption increased firstly and then decreased with the increase of nitrogen rate,and there were no significant difference between treatments of N2, N3and N4. Thetotal water consumption and the proportion of irrigation significantly increased withincreasing irrigation frequency, while the proportion of precipitation and soil waterdepletion had the opposite trend. The soil water consumption amount in differentirrigation treatments showed that W0> W1> W2. Increasing irrigation frequencycould help to improve the water consumption, water consumption intensity and waterconsumption percentage. The effects of nitrogen application were different due to thedifferent precipitation and irrigation conditions. Water consumption percentage of W1from jointing to anthesis was higher under low precipitation condition, and theproportion of water from anthesis to maturity increase in W2. The increase rates ofwater consumption percentage from anthesis to maturity were higher than that fromjointing to anthesis stage with6.3%in W1and2.6%in W2under more precipitationcondition. Irrigation twice in less precipitation year and irrigation once in moreprecipitation year with the N application240kg hm-2were optimal managementpattern, which lead to relatively higher water use efficiency to fully utilize irrigationand rainfall and soil water storage.4. The effects of different irrigation and nitrogen treatments on the temperatureand senescence and grain filling in winter wheatThe daily variation trends of canopy temperature in winter wheat were basicallyidentical curve under different water and nitrogen treatments, and the peak momentsof canopy temperature were different because of different rainfall year type andirrigation conditions. The moderate nitrogen application (N3) can increase the canopytemperature from8:00to10:00, and decrease the canopy temperature from12:00to18:00. The canopy temperature of different treatments decreased with the increase ofirrigation frequency, and the variation amplitude of canopy temperature was low in the treatment of irrigation twice and N application240kg hm-2. The correlationsbetween the canopy temperature during mid to later filling stage and the grain fillingrate were negative with significantly correlation coefficient of-0.29. The temperatureof8:00-18:00for20cm soil increased persistently, with significantly higher value in20cm soil temperature of N application treatment than N0treatment. Increasingirrigation frequency and moderate nitrogen application (N3) could inhibit the20cmsoil temperature increasing rapidly, and delay the plant senescence and promote grainfilling. The correlations between the20cm soil temperature during the filling stageand the grain filling rate were not significant. The activity of CAT and the content ofsoluble protein were improved in moderate nitrogen application (N3), and increasedwith the increase of irrigation times. The contents of Proline and MDA were reducedfirst and then increased with the N application increased, and both decreased with theincrease of irrigation frequency. The correlations between the temperature of canopyand20cm soil during filling stage and MDA were significantly positively in twoyears, and as well as the proline content. The correlations between the temperature ofcanopy and20cm soil during filling stage and the content of soluble protein werenegative in two years.5. Effects of different irrigation and nitrogen treatments on grain yieldThe grain yield increased with the increase of irrigation frequency, while theeffect of N application rate showed a trend of single peak. Grain yield of the appliednitrogen treatments were significantly higher than that of N0treatment. The N2treatment under no irrigation in less precipitation year had the highest yield, while theothers reached the highest at the N application of240kg hm-2(N3) in two years. Theear number increased at first and then reduced with the increase of N application rateunder water deficiency (W0and W1in2010-2011) and relatively enough (W2in2011-2012). The kernels of per spike increased at first and then decreased with theincrease of N application rate in both two years, and with the highest values in N2for2010-2011and N3for2011-2012. The1000grains weight decreased with theincrease of N application rate, and the effects of irrigation on kernels of per spike and1000grains weight were different because of different precipitation and N application.The effects of yield components on yield were different due to the two yield level.The grain yield of winter wheat increased with the increase of spike number whenyield was lower than7500kg hm-2, while the effect of spike number on yield was smallerwhen yield was higher than7500kg hm-2. With the increase of kernels of per spike,grain yield enhanced, and kernels of per spike reached saturation easily under thecondition of low yield with lager yield potential under the condition of high yield. Thevariation amplitude of1000grains weight was lager under different irrigation andnitrogen managements, and its effect on yield was smaller. Therefore, we shouldstrengthen water and fertilizer management and regulation in the field to increase thekernels of per spike on base of stably increase of ear number, further coordinate the1000grains weight for higher yield of winter wheat. The increase rate of irrigationtwice than once was10.7%in2010-2011and1.9%in2011-2012. Therefore,irrigation twice (irrigation at jointing and flowering stage) in less precipitation yearand irrigation once (irrigation at jointing) in more precipitation year with the N application240kg hm-2were optimal management patterns of water and nitrogen inthis region, and which can be recommended in the wheat production with fullyutilization of irrigation water and higher yield and water use efficiency as well.