Effects of Different lrrigation Times and Nitrogen Fertilizer APPlication on Leaf Area lndex and Grain Yield of‘Yujiao 5’

Yongjing Nl，Qunling HE，JinPei Ll，PeiPei ZHP，Xin HP*，Liqin ZHANG，Shijie WANG

1.Shangqiu AcademY of Agricultural and ForestrY Sciences，Shangqiu 476000，China；

2.Guangwu Center Station of XingYang Agriculture TechnologY and Popularization，XingYang 450103，China；

3.Henan lnstitute of Education，Zhengzhou 450046，China

Effects of Different lrrigation Times and Nitrogen Fertilizer APPlication on Leaf Area lndex and Grain Yield of‘Yujiao 5’

Yongjing Nl1，Qunling HE1，JinPei Ll1，PeiPei ZHP1，Xin HP1*，Liqin ZHANG3，Shijie WANG3

1.Shangqiu AcademY of Agricultural and ForestrY Sciences，Shangqiu 476000，China；

2.Guangwu Center Station of XingYang Agriculture TechnologY and Popularization，XingYang 450103，China；

3.Henan lnstitute of Education，Zhengzhou 450046，China

To provide＂more reasonable，more saving and more efficient＂water and fertilizer application proposals，taking ‘Yujiao 5’as the experimental material，the effects of different irrigation times and nitrogen application treatments on the leaf area index and Yield of wheat were studied using three-factor split plot method.The results showed that irrigation times，nitrogen application rate and the ratio of basal to topdressed nitrogen respectivelY had significant effects on the leaf area index，the Yield and component factors of wheat.Under the treatment of W1 （irrigation before sowing），the leaf area index showed a positive linear correlation with nitrogen application rate；under the treatments of W2 （irrigation before sowing and at jointing stage）and W3（irrigation before sowing，at jointing stage and at grain filling stages），the leaf area index showed a positive linear correlation with nitrogen application rate at the jointing stage，booting stage and heading stage；20 d after heading，the leaf area index showed a quadric curve relationship with nitrogen application rate at these stages，and the LAl of N3R2 was the highest.Under different irrigation times，the Yield，ear number and kernels per ear showed quadric curve relationship with nitrogen application rate，1 000-seed weight showed the trend of linear decrease with the increase of nitrogen application rate.Under the treatment combination of irrigation before sowing，at jointing stage and at grain filling stage，nitrogen application rate at 240 kg/hm2and the ratio of basal to topdressed nitrogen of 5:5，the grain Yield （8 609.60 kg/hm2），ear number （688.2×104/hm2）and kernel number per ear （37.9 grains）reached the highest value at W3N3R2，and the grain Yield of W3N3R2 increased bY 144.8%compared to the W1N0.ln conclusion，in Eastern Henan where the rainfall is insufficient at the late growth stage of wheat，the irrigation-saving space in wheat production is relativelY small，but the nitrogen-saving space is relativelY large.

lrrigation；Nitrogen fertilizer；The ratio of basal to topdressed nitrogen；‘Yujiao 5’；Leaf area index；Grain Yield

L eaf is the main organ for photosYnthesis，leaf area has a great effect on the Yield formation of wheat.Precious studies showed that 70%-80%of wheat grain Yield is from the product of canopY photosYnthesis after flowering.However，the interception of wheat canopY to illumination and the efficient utilization of luminous energY mainlY depend on the size of leaf area index［1］.Noisture and fertilizer have a close connection，and the two are important factors influencing the growth and development of leaf，Yield and component factors of wheat［2-4］. Soil moisture deficiencY makes the crops difficult to assimilate adequate nutriment，therebY inhibiting the leaf growth of plants and affecting the leaf area，which will lead to the unreasonable utilization and distribution of luminous energY and the decrease of pho-tosYnthetic efficiencY of the group，thus affecting the Yield formation of wheat grain［5-7］.lncreasing nitrogen application is conductive to increasing the leaf area of wheat，improving canopY structure and increasing wheat Yield，but excessive nitrogen application will make leaf inclination small and the leaf area oversize，which will be bad for the construction of reasonable canopY structure，causing the decrease of wheat Yield［8-10］.

ln recent Years，there have been manY reports on the effects of different irrigation and nitrogen fertilizer treatments on the Yield and component factors of wheat［11-14］.Some scholars thought that there were prominent interaction effect between moisture and nitrogen fertilizer，and the effect of the two on the Yield had obvious positive effect within a certain range，irrigation times and high level of nitrogen would make the Yield-improving effect increase［15-16］.Zhao Xuefei et al.［17］showed that irrigation times and nitrogen application rate had a significant interactive effect on wheat Yield and each Yield component；under different rainfall Years and different fertilitY conditions，irrigation times and nitrogen application rate also had different effects on population dYnamics.Bai Liping et al.［17］indicated that the irrigation at the jointing stage could significantlY improve grain Yield of wheat，especiallY the irrigation at grain filling stage could greatlYimprove 1 000-seed weight.Wang Yuefu et al.［3］held that properlY increasing nitrogen application rate was conducive to the improvement of grain Yield of wheat，but excessive nitrogen application would make the Yield decrease.Therefore，reasonable water and fertilizer application is an important measure improving leaf area index of wheat，fullY excavating Yield potential of the varietY，realizing the high Yield of wheat，and reducing environmental pollution.The previous studies mainlY focused on the effects of the coupling of irrigation times and nitrogen application rate or nitrogen application rate and the ratio of base fertilizer to topdressing on wheat Yield and drY matter accumulation，however，the studies on the effects of irrigation times，nitrogen application rate and the ratio of basal to topdressed nitrogen on leaf area index and Yield of wheat were fewer.Therefore，in the experiment，new wheat varietY ‘Yujiao 5’was used as the experimental material，hoping to find the appropriate irrigation times，suitable nitrogen application rate and reasonable ratio of basal to topdressed nitrogen，therebY giving full plaY to the Yield-increasing potential of moisture and fertilizer，thus providing a theoretical basis for achieving the production objectives of“high Yield，dependable crop and increasing production”in the wheat region of Eastern Henan.

Materials and Methods

ExPerimentalmaterials and the condition of exPerimental field

ln the experiment，the high-Yield winter varietY‘Yujiao 5’bred bY Henan lnstituteofEducationwas chosen.

The experiment was carried out in the farm of Shangqiu AcademY of Agricultural and ForestrY Sciences in October of 2011.The preceding crop of the experimental field was maize，and allofthe maize straw was smashed mechanicallY and returned to the field，the soil texture was moisture soil，and the fertilitY level of 0-20 cm soil was as follows:12.0 g/kg organic matter，68.95 mg/kg hYdrolYzable nitrogen，36.24 mg/kg rapid available phosphorus and 137.28 mg/kg rapidlY available potassium.The precipitation of‘Yujiao 5’in the whole growth period was in Table 1.

ExPerimental design

The fertilizers were urea（46%N），diammonium phosphate（44%P and 16%N）and potassium chloride（60% K）；P and K fertilizers were all applied once as base fertilizer；urea，chicken manure and straw-decomposing inoculant were broadcast in everY plot according to the requirements of treatments.The final seedling number before overwintering was 240×104/hm2. The sowing date was on October 15，the other field management was carried out according to that of high Yield field，the harvesting date was on June 15.

ln the experiment，there were totallY 27 treatments and three repetitions.The split block design of three factors （irrigation times（W），nitrogen application rate（N），the ratio of basal to topdressed nitrogen（R））was adopted. And the irrigation times（W）was set as the main treatment factor and it was divided into the following three levels: W1:irrigation before sowing，W2:irrigation before sowing and at jointing stage，W3:irrigation before sowing，at jointing stage and at grain filling stage；nitrogen application rate（N）was set as the secondarY treatment factor，and it contained five pure nitrogen levels: N1:0 kg/hm2，N2:120 kg/hm2，N3:240 kg/hm2，N4:300 kg/hm2，N5:360 kg/hm2；the ratio of basal to topdressed nitrogen（R）was set as the tertiarY treatment factor，and it contained two levels:R1:the ratio of basal to topdressed nitrogen of 3:7，R2:the ratio of basal to topdressed nitrogen of 5:5. The specific treatments of the experiment were in Table 2.The preceding crop of the experimental field was maize，and all of the maize straw was smashed mechanicallY and returned to the field.The fertilizers were urea（46% N），diammonium phosphate（44%P and 16%N）and potassium chloride （60%K）；P and K fertilizers were all applied once as base fertilizer；urea was broadcast in everY plot according to the requirements of treatments.The area of the plot was 6.5 m×3.7 m，and the guard row was set around the experimental plot.

Measuring items

The surveYs on 10 single plants and plant population were carried out at the jointing stage，booting stage，heading stage and 20 d after heading，moreover，the leaf area index of wheat was calculated.

The leaf area index before heading=The leaf area per plant（m2）×Basic seedlings（×104/hm2）/1 hm2；

Table 2 The experimental treatment

The leaf area index after heading=The leaf area per stem（ear）（m2）× The number of ears（×104/hm2）/1 hm2；

The grain of each plot was harvested，and the theoretical Yield per hectare was calculated according to actual Yield of the plot；1 m with two rows was chosen to calculate the number of ears according to ears？per row；when harvesting，the ears of wheat from 10 plants were drawn randomlY to measure kernels per ear；when the grain was dried，the samples were drawn randomlY to measure 1 000-seed weight，and the difference was within 0.5 g.

Data analysis

Variance analYsis and significance analYsis of difference were carried out using DPS data processing sYstem，and SPSS 19 was used for data regression analYsis and Excel mapping.

Results and Analyses

Effects of different water and fertilizer treatments on the leaf area index of‘Yujiao 5’at the growth Period

As shown in Table 3，irrigation times had a significant effect on the leaf area index of‘Yujiao 5’.After the irrigation at jointing stage，from the surveY data of W1 and W2，it was shown that the leaf area index of each growing period had significant differences，this indicated that the irrigation at jointing stage could effectivelY improve the leaf area index of the whole growth period，which was beneficial to the improvement of wheat population. From the leaf area index of 20 d after heading under the treatments of W2 and W3，it can be seen that the irrigation at grain filling stage significantlY promoted the leaf area index of wheat at the later stage of growth.

From nitrogen application rate and leaf area index，the leaf area index increased significantlY with the increase of nitrogen application rate from the jointing stage to the heading stage.Noreover，the leaf area index of the three stages of growth and development all showed a linear positive correlation with nitrogen application rate，and the correlation coefficients were 0.997 0**，0.988 9**and 0.987 9**，respectivelY；the leaf area index of 20 d after heading showed a quadratic curve relation with nitrogen application rate，and the correlation coefficient was 0.987 9**.At the booting stage，the leaf area index under the treatment of 300 kg/hm2nitrogen application rate was the highest；20 d after heading，the maximum value ofthe leaf area index occurred at the treatment of 240 kg/hm2nitrogen application rate.This showed that the overgrowth of individual leaf at the booting stage affects the coordinative relation between plant and population at the later period，that is，too large leaf population is harmful to the full use of luminous energY，therebY affecting the grain filling and causing the decrease of the Yield.

Under the influence of the ratio of basal to topdressed nitrogen，the leaf area index at the jointing stage was R2＞R1，while from the booting stage to 20 d after heading，the leaf area index was R1＞R2，and the difference was significant.The reasons were:for the ratio of basal to topdressed nitrogen of R1 was 3:7 and R2 was 5:5，under the premise of the same nitrogen application rate，the basal nitrogen application rate of R2 was more that that of R1 before the jointing stage；the dressing rate of R1 was more than that of R2 after the jointing stage，the relativelY sufficient nitrogen fertilizer was beneficial to the growth of plant leaf within a certain range.

Table 5 Effects of nitrogen application rate on the leaf area index of‘Yujiao 5’during the main growth periods under different irrigation times

Effects of different water and fertilizer treatments on the yield and its comPonent factors of‘Yujiao 5’

As seen in Table 4，irrigation times had a significant effect on the Yield and its component factors of‘Yujiao 5’.The Yield，ear number and 1 000-seed weight increased with the increase of irrigation times，and seeds per ear showed increasing trend firstlY and then tended to smooth with the increase of irrigation times.From the Yield of view，the irrigation at jointing stage and at grain filling stage both had significant Yield-increasing effect. From Yield component of view，the effect of the irrigation at jointing stage on it reached significant level，but the effect of the irrigation at grain filling stage was not significant.

On nitrogen application rate，the Yield，ear number and kernels per ear showed the trend of increasing firstlY and decreasing then with the increase of nitrogen application rate，and showed a quadratic curve relation with nitrogen application rate；1 000-seed weight decreased with the increase of nitrogen application rate，and had a negative linear correlation with nitrogen application rate.The correlation coefficients between the Yield，ear number，kernels per ear，1 000-seed weight and nitrogen application rate were 0.993 5**，0.920 3**，0.980 8**and 0.999 5**，respectivelY.The Yield，earnumberand kernelsperear reached the maximum value under the treatment of N3（240 kg/hm2），namelY 7 200.32 kg/hm2，609.71×104/hm2and 35.32 grains，respectivelY，which were obviouslY higher than the other nitrogen application levels；1 000-seed weight reached the the maximum value under the treatment of N0，and the maximum value was 42.92 g.On numerical value，although the Yield under the treatment of 300 kg/hm2nitrogen fertilizer had not significant difference with that under the treatment of 240 kg/hm2nitrogen fertilizer，excessive nitrogen fertilizer increased the cost，reduced the economic benefit of agricultural production，and caused the environmentalpollution.Underthe treatments of the two ratios of basal to topdressed nitrogen，the values of the Yield，ear number and kernels per ear under the treatment of the ratio of basal to topdressed nitrogen of 5:5 were larger than those under the treatment of the ratio of basal to topdressed nitrogen of 3:7，and the difference was significant；howev-er，1 000-seed weight was just the opposite.These showed that the effect of nitrogen application rate on the Yield of‘Yujiao 5’is realized mainlY bY effective ear number and kernels per ear at the mature period.

Effects of nitrogen aPPlication rate on the leaf area index of‘Yujiao 5’under different irrigation times

As shown in Table 5，under different irrigation times，the leaf area index increased significantlY with the increase of nitrogen application rate from jointing stage to heading stage，and showed a linear positive correlation with nitrogen application rate.20 d after heading，the leaf area index showed a linear relation with nitrogen application rate in the condition of W1，however，the leaf area index showed a quadratic curve relation with nitrogen application rate in the conditions of W2 and W3.Comparing the N3 and N4 treatments in the conditions of W2 and W3，it was drawn that the average dailY descending rate of the leaf area underthetreatmentsofW2N3and W2N4 from heading to 20 d after heading were 0.346 and 0.378 m2/m2，respectivelY；and that under the treatments of W3N3 and W3N4 were 0.324 and 0.356 m2/m2，respectivelY.Therefore，excessive nitrogen application rate will accelerate the descending rate of leaf area coefficient and chlorophYll content in ear leaves at the late growth stage of wheat，making the leaves ageing in advance，and causing the decline of utilization efficiencY of leaves to illumination；irrigation at grain filling stage can improve nitrogen use efficiencY，effectivelY delaY the senescence of lower leaf，increase photosYnthetic use efficiencY，and improve the conversion of luminous energY.

Table 6 Effects of nitrogen application rate on the Yield and its component factors of‘Yujiao 5’under different irrigation times

Table 7 The leaf area index of‘Yujiao 5’during the main growth periods under different water and fertilizer treatment combinations

Effects of nitrogen aPPlication rate on the yield and its comPonent factors of‘Yujiao 5’under different irrigation times

As seen in Table 6，ear number and kernels per ear increased with the increase of nitrogen application rate underthe treatmentofW1，and showed a linear positive correlation with nitrogen application rate；under the treatments of W2 and W3，ear number and kernels per ear showed the variation trend of increasing firstlY and decreasing then，and showed aquadratic curve relation with nitrogen application rate.Under the condition of W2，ear number and kernels per ear reached the highest under the condition of N3；under the condition of W3，althoughearnumberreached the highest under the condition of N2，the difference with N3 was not significant，kernels per ear reached the highest under the condition of N3，and followed the sequence of W3N3＞W2N3＞W1N4.These showed that irrigation times is the main effect factor regulating and controlling ear number and kernels per ear；if the moisture is adequate，the nitrogen use efficiencY of suitable nitrogen application rate will be further improved，therebY benefiting the increase of ear number and kernels per ear.

Table 8 Effects of different water and fertilizer interactions on the Yield and its component factors of‘Yujiao 5’

Under the treatment of irrigation times，1 000-seed weight showed a negative linear correlation with the increase of nitrogen application rate，and the maximum value appeared at N0.When the nitrogen application rate was 300 kg/hm2，1 000-seed weight respectivelY decreased bY 8.66% ，15.95%and 17.45%compared with 0 kg/hm2.These indicated that the decreasing range of 1000-seed weight is small with the increase of nitrogen application rate under insufficient irrigation，but if the decreasing range of 1 000-seed weight is viewed as the superimposed effect of irrigation times and nitrogen application rate，then the interaction effects of irrigation before sowing and at jointing stage as well as nitrogen application rate on 1 000-seed weight are almost the same bY comparing the values，the interaction effect of irrigation at grain filling stage and nitrogen application rate on 1 000-seed weight is not significant.

On the Yield，under the treatment of W1，the Yield increased with the increase of nitrogen application rate，however，the differences among N1，N2 and N3 were not significant，N4 had significant differences with the other treatments.Under the treatments of W2 and W3，the Yield showed the variation trend of increasing firstlY and decreasing then，and the maximum values appeared at N3 treatment，which were 8 098.16 and 8 296.42 kg/hm2，respectivelY.The relationship between the Yield and nitrogen application rate under the treatments of W1，W2 and W3 was as follows:

From the above equations，it can be seen that the nitrogen application rates under the treatments of W2 and W3 were 301.536 and 290.837 kg/hm2，respectivelY，thus it can calculate that the maximum values of the Yield of‘Yujiao 5’were 8 087.956 and 8 215.973 kg/hm2，respectivelY.Therefore，increasing the irrigation at grain filling stage can effectivelY improve nitrogen use efficiencY，and reduce the application levels of nitrogen fertilizer，therebY significantlY improving the Yield；bY comparing the theoretical Yield and the Yield from the equations，it can be drawn that the interaction between irrigation times and total nitrogen application rate can not reach the optimization of irrigation and fertilizer application，the ratio of basal to topdressed nitrogen is also the important factor affecting the Yield and the component factors.

Effects of different water and fertilizer interactions on the leaf area index ofwinterwheatduring the growth Period

Under different irrigation times，the leaf area index of the wheat at the jointing stage changed with nitrogen application rate，and had a linear positive correlation with nitrogen application rate.This indicated that the leaf area index at the jointing stage ismainlY affected bY the application of basal nitrogenous fertilizer，and reaches the significant level.The leaf area index of the wheat at the booting stage and heading stage showed a positive correlation linear variation with the generation of nitrogen application rate，and that under different nitrogen application rates had significantdifferences；20 d after heading，the leaf area index under W1 condition increased with the increase of topdressed nitrogen at the jointing stage，but the difference on the leaf area index of each treatment combination after N3R1 （topdressed nitrogen was 168 kg/hm2）was not significant.Under the conditions of W2 and W3，the leaf area index showed the trend of increasing firstlY and decreasing then with the increase of topdressed nitrogen，and the maximum value appeared at N3R2（in Table 7）.

Table 9 The variance analYsis of the Yield and its component factors of‘Yujiao 5’（F value）

From average value，under the conditions of the same nitrogen application and the same ratio of basal to topdressed nitrogen，W2＞W1 and W3＞W1，the differences of each treatment combination under W2 and W3 were not significant.ln the 27 treatmentcombinations，the treatment combination W3N4R2 had the peaked leaf area index at the jointing stage，and had not significant differences with W1N4R2 and W2N4R2；the treatment combination W2N4R1 had the peaked leaf area index at the booting stage，and had not significant difference with W3N4R1.However，too large leaf area was bad for the Yield，so W3N4R1 had not significant difference with W2N4R1；the treatment combination W3N3R2 had the peaked leaf area index in 20 d after heading，which had significant difference with the treatment combination W2N3R2.These showed that the effect of water and fertilizer treatment on the leaf area index of the wheat is mainlY at the filling stage，thus it is the critical period determining the Yield.

Effects of different water and fertilizer interactions on the yield and its comPonent factors of winter wheat

As seen in Table 8，from different irrigation times，under the condition of W1，the differences of ear number and 1 000-seed weight under the ratio of basal to topdressed nitrogen of 3:7 and 5:5 were not significant，but the difference of kernels per ear under the two was significant.Under the condition of W2，the difference on the Yield component under the two ratios was significant.Under the condition of W3，the differences on the Yield，ear number and kernels per ear under the two ratios were significant，but for 1 000-seed weight，the difference was not significant.From the combinations of irrigation times and the ratio of basal to topdressed nitrogen，ear number under the treatment of W3R2 was higher than that of the other treatments，kernels per ear under the treatment of W2R2 reached the maximum value，and the difference with W3R2 was not significant；1 000-seed weight under the treatment of W3R1 reached the maximum value，and it was significantlY higher than that of the other treatments.From the combinations of nitrogen application rate and the ratio of basal to topdressed nitrogen，Yield component under the treatment of N3R2 reached the maximum value，and ear number and kernels per ear under the treatment had significant differences with those of the other combinations.

Under the condition of W1，the Yield under different ratios of basal to topdressed nitrogen had not significant differences，under the conditions of W2 and W3，that under different ratios of basal to topdressed nitrogen had significant differences.Under different nitrogen application levels，the Yield under different ratios of basal to topdressed nitrogen in N0 and N4 levels had not significant differences，while that in N1，N2 and N3 levels had significant significant differences.Too little or excessive nitrogen application all reflect the regulating difference of different ratios of basal to topdressed nitrogen on the Yield.From the combinations of irrigation times and the ratio of basal to topdressed nitrogen，the Yield of wheat under the treatment of W3R2 reached the maximum value，namelY 7 226.94 kg/hm2，which increased bY 48.47%compared with the combination W1R1 with the minimum value.From the combinations of nitrogen application rate and the ratio of basal to topdressed nitrogen，the Yield of wheat under the treatment of N3R2 reached the maximum value，namelY 7 348.74 kg/hm2，which increased bY 75.61%compared with no nitrogen. From the interactions among irrigation times，nitrogen application rate and the ratio of basal to topdressed nitrogen，the combination with the highest Yield was W3N3R2 whose Yield was 8 609.60 kg/hm2，which increased bY 144.80% compared with control combination W1N0.ln the 27 treatment combinations，except 1 000-seed weight，the optimal combination of the Yield，ear number and seeds per ear was W3N3R2.

Therefore，under the cultivation measures of adequate irrigation（irrigation before sowing，at jointing stage and at grain filling stage）+total nitrogen application at 240 kg/hm2+theratio of basal to topdressed nitrogen of 5:5，the objective of high Yield of winter wheat can be realized.

Thevarianceanalysisofwheat yield and its comPonent factors

From the variance analYsis table of the Yield and its component factors of‘Yujiao 5’，it can be seen that the effects of irrigation times （the main treatment factor），nitrogen application rate （the secondarY treatment factor）and the ratio of basal to topdressed nitrogen（the tertiarY treatment factor）on the Yield，ear number and kernels per ear all reached extremelY significant level（P＜0.01），irrigation times and nitrogen application rate had extremelY significant effect on 1 000-seed weight（P＜0.01），the effect of the ratio of basal to topdressed nitrogen on 1 000-seed weight was also significant（P＜0.05）. The interaction of irrigation times and nitrogen application rate had extremelY significant effect on the Yield and its component factors except kernels per ear.The interaction of irrigation and the ratio of basal to topdressed nitrogen just had extremelY significant effect on the Yield，but the effect on the Yield component was not significant（P＞0.05）.The interaction of nitrogen application rate and the ratio of basal to topdressed nitrogen had extremelY significantregulating effecton the Yield，ear number and kernels per ear，but the effect on 1 000-seed weight was not significant.lrrigation times，nitrogen application rate and the ratio of basal to topdressed nitrogen had extremelY significant interaction effect on the Yield.

Conclusions and Discussions

To better understand the effect of water and fertilizer interaction on the leaf area index and the Yield of wheat，bY three-factor split plot experiment，the effects of water and fertilizer on the leaf area index and the Yield as well as its Yield component of new wheat varietY ‘Yujiao 5’were studied detailedlY from the aspects of irrigation times，nitrogen application rate and the ratio of basal to topdressed nitrogen from single factor regulation，two-factor coordination and three-factor interaction.

ln the experiment，the results showed that irrigation times and nitrogen application rate can significantlY increase the leaf area index of wheat during the main growth periods，which is basicallY consistent with the conclusion of Zhao Xuefei et al.［15］.The effect of the ratio of basal to topdressed nitrogen on the leaf area index of wheat during the main growth periods reaches the significant level，and the leaf area index increases with the increase of irrigation times and nitrogen application rate.Under the nitrogen application rate at 300 kg/hm2after the irrigation at the jointing stage，the leaf area index of 20 d after heading was lower than that under the nitrogen application rate at 240 kg/hm2.The increase of irrigation times significantlY increases the ear number，kernels per ear and 1 000-seed weight of wheat，with the increase of nitrogen application rate，ear number and kernels per ear increase significantlY，while 1 000-seed weight decreases.All in all，adequate irrigation+appropriate nitrogen application+rational ratio of basal to topdressed nitrogen can make wheat Yield form stable and coordinated population，therebY laYing a solid foundation for the high Yield of wheat.

ln the experiment，when the theoretical Yield of the wheat under the conditions of W2 and W3 without considering the the ratio of basal to topdressed nitrogen respectivelY reached the highest，the theoretical nitrogen application rate was higher than actual nitrogen application rate bY 50-60 kg/hm2，this showed that the ratio of basal to topdressed nitrogen is of important significance in nitrogen fertilizer treatment.Wang Yuefu et al.［19］studied thatthe absorptive amountof wheat plant to basal nitrogen was higher than the absorptive amount to topdressed nitrogen at the jointing stage in the medium-and high-fertilitY wheat field，while the low-fertilitY wheat field was just opposite.This experiment was conducted in the medium-and high-fertilitY wheat field，the Yield of the wheat under the ratio of basal to topdressed nitrogen of 5:5 was significantlY higher than that of 3:7，which was consistent with the previous research result.Hao Daicheng et al.［20］found that‘Yumai 49’and‘Lankaoaizaoba’respectivelY reached the super high Yield under the nitrogen application rates of 180 and 270 kg/hm2and the ratio of basal to topdressed nitrogen of 5:5；in the experiment，the Yield of‘Yujiao 5’reached the maximum value under the three times of irrigation，the nitrogen application rate of 240 kg/hm2and the ratio of basal to topdressed nitrogen of 5:5.

Due to the effects of different cultivars，different climatic conditions and different fertilitY of wheat field on reasonable water and fertilizer management of super high Yield wheat，anY one of the differences maY cause the inconsistent experimental result.Because there is less precipitation at the late growth period of the wheat in Shangqiu areas，irrigation at grain filling stage has significant Yield-increasing effect on‘Yujiao 5’.Therefore，for the wheat field areas of Shangqiu areas to which the rainfall condition is similar，irrigation at grain filling stage is of great importance for the increase of wheat Yield.For the wheat field with abundant rainfall and high fertilitY，the irrigation times and nitrogen application rate can be reduced relativelY，which helps to meet the production requirements of“saving water and saving fertilizer”，therebY realizing the objectives of preserving the ecological environment and reducing pollution.

ln the studY，onlY the effect of water and fertilizer on the leaf area index and the Yield was studied，and it still needs to further studY the effect of water and fertilizer interaction on photosYnthesis，therebY studYing its effect on the Yield structure，or it can expand to the effect of water and fertilizer on the qualitY of wheat.

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ResPonsible editor：Yong XP

ResPonsible Proofreader：Xiaoyan WP

不同灌水次数与氮肥运筹对‘豫教5号’叶面积指数及产量的影响

倪永静1，贺群岭1，李金沛2，朱培培1，胡 新1*，张丽琴3，王世杰3， （1.商丘市农林科学院，河南商丘 476000；2.荥阳市农业技术推广广武中心站，河南荥阳450103；3.河南教育学院，河南郑州 450046）

为给冬小麦提供"更合理、更节约、更高效"的水肥运筹技术方案，以'豫教5号'为试验材料，采用三因素裂区方法研究了不同灌水次数和施氮处理对小麦叶面积指数和产量的影响。结果表明，灌水次数、施氮量以及基追比例分别对小麦叶面积指数、产量及构成因素有显著影响。在W1（底墒水）处理下叶面积指数与施氮量均呈线性正相关关系；在W2（底墒水+拔节水）、W3（底墒水+拔节水+灌浆水）处理条件下，拔节期、孕穗期、抽穗期的叶面积指数与施氮量呈线性正相关关系，抽穗后20天与施氮量则呈二次曲线关系，且以N3R2为最大值。在不同灌水次数条件下，产量、穗数、穗粒数与施氮量呈二次曲线关系，千粒重随施氮量的增加呈线性下降趋势。在灌溉底墒水+拔节水+灌浆水、施氮量为240 kg/hm2及基追肥5：5处理组合下实现了水肥的高效配合，产量、穗数、穗粒数分别为8 609.60、688.2×104/hm2、37.9粒，其中产量比对照W1N0（3 517.5 kg/hm2）增产144.8%。由此可知，在小麦生长后期降雨量偏少的黄淮豫东地区，小麦生产中灌溉水的节约空间相对较小，氮肥的节约空间则相对较大。

灌溉；氮肥；基追比；‘豫教5号’；叶面积指数；产量

国家《农业科技成果转化资金》项目：小麦新品种的中试示范及育种家种子扩繁（2013GB2D000300）；国家现代农业产业技术体系专项资金（CARS-03）。

倪永静（1983-），女，河南滑县人，助理研究员，硕士，主要从事小麦遗传育种及栽培方面研究，E-mail：nyj317@163.com。*通讯作者，研究员，主要从事小麦栽培及育种方面研究，E-mail：huxin2699552@163.com。

2015-04-20

Supported bY the National Project of Transformation Fund for Agricultural Science and TechnologY Achievements:Pilot Production and Demonstration of New Wheat VarietY and the Propagation of Breeder Seed （2013GB2D000300）；The Special Fund of National Nodern Agricultural lndustrY TechnologY SYstem（CARS-03）.

*Corresponding author.E-mail:huxin2699552@163.com

Received:April 20，2015 Accepted:August 24，2015

修回日期 2015-08-24