Synergy Effects Of Water And Fertilizer Coupling On Winter Wheat

The pool-culture experiment with Changhan58as experimental material was conducted.Photosynthetic, biomass, yield, chlorophyll content indicators and soil moisture distributionof16different water and fertilizer coupling treatments were compared and analyzed in orderto explore growth and physiology responses under water-fertilizer coupling in wheat growthstage, to provide a theoretical basis and reference for water-fertilizer research and alsoestablish a suitable water-fertilizer management mode for winter wheat in dryland areaswithout irrigation conditions. The main results were listed as follows:1. The effects of water and fertilizer coupling on photosynthetic characteristics of winterwheat flag leaf were:1) the effect of water on the flag leaf photosynthetic characteristics wasgreater than the fertilizers’ under different water and fertilizer coupling treatments, and thereare a positively correlated (P <0.05) between the indexes of flag leaf photosyntheticcharacteristics and the water under the same fertilizer treatments.2）In the wheat floweringperiod, under the medium level of the fertilizer rate, compared with the no irrigation, lowirrigation amount treatments, the Pn of low irrigation, medium irrigation treatments wereincreased by3.25%(P <0.05),5.01%(P <0.05) respectively;3）Under the sufficient soilmoisture, the Pn, Gs, Tr of winter wheat flag leaf was improved with the increasing offertilizing amounts. In the wheat flowering period, under the medium level of the irrigationrate, compared with the no fertilizer, low fertilizer amount treatments, the Pn of low fertilizer,medium fertilizer treatments were increased by2.45%(P <0.05),3.19%(P <0.05)respectively; The medium irrigation and fertilizer rate treatment was best for the wheat flagleaf photosynthetic characteristics.2. Chlorophyll and carotenoids content of winter wheat flag leaf in different water andfertilizer coupling treatments decreased gradually from filling to maturity. Early to mid filling,it decreased slowly, and from mid to maturity, it decreased sharply, indicates photosyntheticproducts were gradually shifted to grain. In mid filling, the Chlorophyll content of the lowirrigation and medium fertilizer rate treatment is the highest (4.29mg/g), to carotenoidscontent, it is the low irrigation and fertilizer rate treatment (0.478mg/g) compared with other treatments. In medium fertilizer treatment (Y2), Chlorophyll content of low medium highirrigation treatments were significantly increased by15.85%,10.49%,9.76%(p<0.05)respectively compared with no irrigation treatment, and the different in carotenoids contentwere15.85%,10.49%,9.76%(p<0.05) respectively. And the difference was not significantamong low medium high irrigation treatment. In high irrigation treatment (W3), Chlorophyllcontent of high medium low fertilizer treatments were significantly increased by10.11%,15.57%,14.86%(p<0.05) respectively compared with no fertilizer treatment, and thedifferent in carotenoids content were3.61%,8.43%,6.75%(p<0.05). Under well-wateredconditions, the increasing on flag leaf chlorophyll content is not obvious in the excessfertilizer inputting (Y3). Fertilizer inputting in wheat grain filling stage can produce morecarotenoids, resulting in a high yield, the impact on carotenoids increasing with increasingfertilizer was not significant.3. In middle irrigation conditions (W2), the order of the average soil moisture in0-200cm soil is Y3>Y1>Y2in wheat grain filling stage. The water utilization of Y2wasgreater than Y1Y3and Y0. In40cm layer, Soil moisture content of Y2Y1Y3weresignificantly decreased by36.38%,27.05%,23.95%(P<0.05) respectively. In this stage, grainwas filling, water using was greatly enhanced, soil moisture content is reduced magnitudelarger. During each growth stages, the soil moisture of Y2, Y1treatments was lower,indicated that Y2, Y1treatments had more moisture absorption, high water use efficiency.4. Under the same water conditions, the wheat biomass increased gradually in turninggreen and booting stages, in filling and harvest stages it increased and then decreased withfertilizer amount increasing. In the medium fertility level, the biomass was the largest, Underthe flowering period, in each irrigation conditions, biomass trended differently. Low volumeirrigation (W1), biomass reduced with the amount of fertilizer, it may be affected by waterstress, fertilizer increasing hampered the limited water use of crop and reduced theaccumulation of biomass, and with the soil containing increasing (W3), biomass increasedgradually with the fertilizer increasing.5. Impact of water on the yield is greater than fertilizer, in inappropriate irrigation(W1/W0), the yield is relatively low in any fertilizer level, reflecting that the yield of droughtwheat was sensitive to moisture than fertilizer. Only if the water is appropriate, fertilizer isthe main reason for the yield increasing. the treatment of highest grain yield was the mediumirrigation and fertilizer treatment (6628.94kg/hm2), followed by was medium irrigation andhigh fertilizer, high irrigation and fertilizer (W3Y3), medium irrigation and low fertilizer(W2Y1), yields were6435.82kg/hm2,6406.45kg/hm2and6366.71kg/hm2Respectively, and were significantly increased by36.11%,35.49%,34.65%(P<0.05)compared with CK(Y0W0). The coupling effect of Y3and W0, Y2and W0was poor.6. Water and fertilizer use efficiency in different water and fertilizer coupling: Soilmoisture directly affected water consumption and water use efficiency of crops. In eachirrigation conditions, WUE of W2(13.93kg/mm·hm2) was greater than W1(13.60kg/mm·hm2)、W0(13.29kg/mm·hm2) and W3(12.56kg/mm·hm2). In W1、W2and W3irrigationconditions, WUE increased and then decreased with fertilizer amount increasing. In W2condition, compared with Y0, Y1and Y3, WUE of Y2was significantly improved21.56%,15.09%,12.51%respectively. Under certain conditions of fertilization, the nitrogen fertilizeruse efficiency increased and then decreased with irrigation increasing. NUE of the mediumirrigation and low fertilizer rate treatment was up to40.40kg/kg, high irrigation and nofertilizer rate treatment was the smallest (0.53kg/kg). Overall, in Y1fertilizer rate, NUE wasthe highest compared with Y2(5.49kg/kg)、Y3(3.28kg/kg). In Y2fertilizer rate, NUE of W2was significantly improved4.39times3.80times respectively, NUE of W3was significantlyimproved4.11and3.56times respectively.