| Winter wheat and summer maize were the main crops of agricultural production in the North C hina Plain of China.Unreasonable application of nitrogen and irrigation not only caused high cost of consumption,may a lso result in deficient groundwater and environment.This article hopes to explore planting pattern,residual effect of nitrogen fertilizer of previous crop and irrigation response to photosynthetic characteristics,leaf and soil water signal,radition and water use efficiency,and yield of winter wheat,to solve the problem of local seasonal drought and nitrogen,eventually provide theoretical basis for agricultural personnel to apply reasonable irrigation and nitrogen in production practice.The experiment was conducted at Agronomy Experimental Station(36°09? N,117°09? E)of production area of winter wheat and summer maize,during 2014,2015 growing season of summer maize and 2015-2016 growing season of winter wheat,Taian,Shandong Province,China.The summer maize(Zhengdan 958)was planted after winter wheat was harvested without tillage under 62500 /hm2.The planting pattern of 30 cm row spacing and furrow sowing "20 + 40" of winter wheat were replaced with 50,60 row spacing and 60 cm ridge tillage of summer maize,respectively.Nitrogen was 112.5 kg/hm2 and 225 kg/hm2 during winter wheat.The experiment of summer maize was rainfall without application of nitrogen and irrigation.The Jimai 22,winter wheat(Triticum aestivum L.)cultivars,was planted in plots of 3×3 m2 size under densities of 200 × 104 /hm2.Three irrigation levels(50+50,100,100+100)were allocated to main plots,and three planting patterns viz.30 cm uniform row planting pattern(U),“20” cm double-double planting pattern(DD),“20+40” cm furrow planting pattern(F)were kept in sub-plots.Total irrigation amount 100(W1)and 200 mm(W3)of water were applied 1/2 to irrigated winter wheat plants at jointing stage and heading stage,respectively.Total irrigation amount 100 mm(W2)of water was applied to irrigated winter wheat plants only at jointing stage.The result follows: 1 Summer maize experiment 1.1 Photosynthetically active radiationThe PAR capture ratio(C R)and penetration ratio(PR)of N1 and N2 were 73.8 and 76.3%,existed significant difference(P < 0.05),PAR(RR)and PR)of N1 was 4% and 8.9% higher than that of N2(P > 0.05).C R of L60 and P60 were 77.1 and 73.0%,existed significant difference(P < 0.05),RR and PR of P60 was 2.8% and 14.9% higher than that of L60(P > 0.05).Under N2 condition,CR and RR of P50 and P60 were almost equally,P60 could effectively reduce the PAR(PR).1.2 Photosynthetic characteristicsCompared with P60,L60 maintained higher CCI,LAI and Pn,during the R2-R4,decreased magnitude of CCI and LAI of L60 and P60 was 34.8%,36.6% and 48.1%,48.7%,respectively.N2 and ridge tillage treatments could increase CCI,LAI and Pn.Further,N2 and ridge tillage reduced decreased magnitude of CCI and LAI,extended the leaf function period,especially late growth stage.Under N2 condition,CCI,LAI and Pn of P60 were higher than that of P50.1.3 Water signalLeaf water potential(?w)of N1,N2 were-1.52,-1.58,and existed significant difference(P < 0.05).At R0,R3 and R4,?w of N2 was significa nt higher than that of N1(P < 0.05).Soil water content(SWC)of 0-40,0-120 cm and soil water storage(SWS)of L60 increased by 3.6,2.0% and 2.0%.RWC and ?w of L60 was significant higher than that of P60(P < 0.05).1.4 Radiation and water use efficiencyCompared with N1,radiation use efficiency(RUE)of N2 increased by 2.6%(P > 0.05),and water use efficiency(WUE)of N2 was significant higher than that of N1(P < 0.05).RUE of L60 was significant higher than P60(P < 0.05).Compared with P60,WUE of L60 was increased by 6.1%(P > 0.05).Yield was significantly and positively correlated with WUE(P < 0.01),correlation with RUE was not significant(P > 0.05),PAR(CR)correlation with RUE was not significant(P > 0.05),suggesting that ridge tillage formed reasonable closed canopy,prevented ETA and increased WUE and RUE,raised yield.1.5 Yield and yield componentsCompared with N1,per-plant kernel number(KNP),stem diameter(SD),ear diameter(ED),ear length(EL),harvest index(HI),yield of N2 increased by 9%,5.5%,2.3%,7.1%,11.9%,13%,respectively(P < 0.05).Compared with P60,KNP,Yield,HI,plant height(PH),SD,ED,EL and row number(RN)of L60 increased by 5.9%,7.1%,5.4%(P < 0.05),3.2%,1.9%,4.7%,1.7%,5.4%(P > 0.05).KNP,EL and HI of P60 were significant higher than that of P50(P < 0.05).2 Winter wheat experiment 2.1 Population develop dynamicsDD planting pattern increased stem number in early growth stage,but enlarged descent range during late growth stage,F planting pattern maintained higher effective tiller.F planting pattern maintained higher LAI and delayed descent range in late growth stage.The stem number and LAI of winter wheat were increased with increased irrigation amount,and with increased irrigation frequency under the same irrigation amount.2.2 Canopy photosynthetic active radiationThe order of the proportion of canopy photosynthetic active radiation was CR > PR > RR.F planting pattern significant increased CR and RR,decreased PR.Contrary to tendency of PR,trend of CR was increased with increased irrigation amount,and with increased irrigation frequency under the same irrigation amount.F planting pattern significantly increased CR of 0-40 cm and aboveground 40 cm,DD planting pattern only significantly increased CR of aboveground 40 cm.CR was increased with irrigation amount for aboveground 40 cm,decreased C R of 0-40 cm,both decreased with increased frequency.2.3 Leaf physiological characteristicsF planting pattern significant increased CCI,Pn and Tr and delayed descent range of CCI and Pn in late growth stage.Increasing irrigation amount significant increased CCI,Pn and Tr,and delay decent range of CCI and Pn,increasing irrigation frequency also had the same trend.2.4 Farmland microclimate of winter wheatDD planting pattern significantly was decreased in air temperature of 5 and 50 cm,and increased relative humidity.F planting pattern was decreased in soil temperature of 0,5,10,15 cm.Contrary to the trend of air relative humidity,temperature of aboveground 5cm,50 cm and underground 0-15 cm decreased with increasing irrigation amount,and with irrigation frequency under the same irrigation amount.2.5 Relationship among grain yield,radition use efficiency and water use efficiencyF planting pattern was not only improved significantly the different organs and total dry matter accumulation,but also adjusted reasonably allocation in different organs at different growth stage,and improved RUE,WUE,related parameters for grain yield and grain yield components,decreased sterile spikelet number.Increasing irrigation amount increased dry matter accumulation of different organs,related parameters for grain yield and grain yield components,but decreased sterile spikelet number;Under the same irrigation amount,dry matter accumulation of different organs,related parameters for grain yield and grain yield components were increased with irrigation frequency,plant height,spike length and sterile spikelet number were contrary to it. |
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