| 1Effects of delayed irrigation at jointing stage and irrigation amount on waterconsumption characteristics and yield formation of wheatThe experiments were conducted in the experimental farm of Shandong AgriculturalUniversity in Taian, Shandong during2007~2008wheat growing season with high-yieldwheat cultivar Jimai22. The precipitation amount in wheat growing season was as follows:21.1mm during the stage from sowing to pre-wintering,12.5mm from pre-wintering toreviving,13.8mm from reviving to jointing,57.3mm from jointing to anthesis,37.0mmfrom anthesis to maturity. Tow irrigation were given in wheat growing season. The firstirrigation was given at jointing stage or10d after jointing stage respectively. Moreover, therespected relative soil water content in0–140cm soil layer after the first irrigation was65%,75%,80%respectively, and which was70%after the second irrigation at anthesis stage in alltreatments. W1(65%), W2(75%), W3(80%) represented irrigation treatments at jointingstage, and DW1(65%), DW2(75%), DW3(80%) represented irrigation treatments on10dafter jointing. W0denoted no irrigation treatment. The object of this study was to expound theeffects of delayed irrigation at jointing stage and irrigation amount on water consumptioncharacteristics and yield formation of wheat.1.1Effects of delayed irrigation at jointing stage and irrigation amount on waterconsumption characteristics of wheatUnder the same irrigation level, the daily water consumption of DW2and DW3treatment was separately lower than that of W2and W3treatment from jointing to10d afterjointing, but higher than that of W2and W3treatment separately from10d after jointing toanthesis. The results indicated that supplementary irrigation on10d after jointing wasbeneficial to meet the water demand of wheat at booting stage.In the treatments irrigated at10d after jointing stage, soil water consumption in0–120cm soil layers of DW2was lower than that of DW1, and higher than that of DW3, from jointing to anthesis. However, the daily water consumption from jointing to anthesis,irrigation amount and water consumption amount during the whole growing season of DW2treatment were higher than those of DW1, and lower than those of DW3. It showed that soilwater consumption in0–120cm layers decreased from jointing to anthesis, irrigation amountand water consumption of whole growth season increased with the increasing of irrigationamount on10d after jointing.1.2Effects of delayed irrigation at jointing stage and irrigation amount on carbon andnitrogen metabolism of wheatUnder the same irrigation level, photosynthetic rate of flag leaf after anthesis, themaximal photochemical efficiency (Fv/Fm) and actual photochemical efficiency at29d afteranthesis, dry matter accumulation amount and nitrogen accumulation amount after anthesis inDW2and DW3treatment were higher than those in W2and W3treatment respectively. Butdry matter translocation amount from vegetative organs to grains and nitrogen translocationamount from vegetative organs to grains of DW2and DW3treatment were lower than thoseof W2and W3respectively. The results suggested that supplementary irrigation on10d afterjointing was favorable to delay the senescence of flag leaf, improve photosynthetic rate of flagleaf and increase dry matter accumulation and nitrogen accumulation amount after anthesis.Under the condition of the treatment irrigated on10d after jointing, photosynthetic rateof flag leaf of DW2treatment on28d after anthesis was significantly higher than that ofDW1and DW3. Moreover, dry matter accumulation amount of DW2after anthesis washigher than that of DW1, and there was no significant difference between DW2and DW3treatment. However, nitrogen accumulation amount of DW2was higher than that of DW3.The results elucidated that DW2treatment whose soil relative water content reached75%after supplementary irrigation on10d after jointing, was beneficial to increase dry matteraccumulation and nitrogen accumulation in wheat after anthesis.1.3Effects of delayed irrigation at jointing stage and irrigation amount on wheat yield,wheat quality and water use efficiencyUnder the same irrigation level, the spike number of DW2and DW3was separatelylower than that of W2and W3, the grain number per spike,1000-grain weight, grain yield,water use efficiency and irrigation benefit of DW2and DW3were higher than those of W2 and W3. However, comparing to W2and W3, there's no significant difference in wet glutencontent, water absorption, dough developing time and dough stability time. These resultssuggested that supplementary irrigation on10d after jointing was beneficial to increase grainyield, water use efficiency and irrigation benefit, but has no significant effect on grain quality.Under the condition of the treatment irrigated on10d after jointing, the grain yield ofDW2treatment whose soil relative water content reached75%after supplementary irrigationon10d after jointing, was higher than that of DW1, but there was no significant differencebetween DW2and DW3. Furthermore, the water use efficiency of DW2was higher than thatof DW3, the irrigation benefit of DW2was higher than that of DW1and DW3. In addition,grain protein content and wet gluten content of DW2were also relatively higher than those ofthe other treatments. DW2treatment was the best treatment in this study.2Effects of tillage practice and irrigation stage on water consumption characteristicsand yield formation of wheatThe experiments were conducted in Shiwang village, Yanzhou, Shandong, during2008~2009growing season with high yield wheat cultivar Jimai22. The precipitation was13.6mm from sowing to pre-wintering,6.7mm from pre-wintering to reviving,28.9mmfrom reviving to jointing,54.9mm from jointing to anthesis, and26.3mm from anthesis tomaturity. Five tillage treatments, which were strip rotary tillage (SR), strip rotary tillage aftersubsoiling (SRS), rotary tillage (R), rotary tillage after subsoiling (RS) and plowing tillage (P)respectively, were designed during2007~2008growth seasons. In this experiment, the sametreatment was designed in the same experimental plot of2007~2008growing seasonexperiment. However, SRS and RS treatments were no longer subsoiling in order to study theafter-effect of subsoiling. In this study, three irrigation stage treatments were designed undereach tillage, which were jointing+anthesis (W1),10d after jointing+anthesis (W2),10dafter jointing+10d after anthesis (W3), and no irrigation was as the control (W0). Theaverage relative soil water content in0–140cm layer was75%after irrigation. The effects oftillage and irrigation stage on water consumption characteristics and yield formation of wheatwere researched in this study. 2.1Effects of tillage practice and irrigation stage on water consumption characteristicsof wheatUnder the same irrigation stage, soil water consumption amount in80-160cm layer ofSRS was higher than that of the other treatments from anthesis to maturity, but the waterconsumption percentage was lower than that of the other treatments from sowing to jointingand from jointing to anthesis. Moreover, water consumption amount from anthesis to maturityand its percentage to total water consumption amount in whole growing season was higherthan that of the other treatments. In addition, irrigation amount of SRS in wheat growingseason was lower than that of R, RS and P treatment, and soil water consumption amount washigher than that of the other treatments. However, total water consumption amount was lowerthan that of RS treatment, and there's no significant difference between SRS and P treatment.The results showed that SRS treatment promoted the absorption of soil water, and wasfavorable to increase water consumption from anthesis to maturity. Furthermore, SRStreatment was also beneficial to decrease irrigation amount in wheat growing season, and savewater resources.Under the same tillage, The irrigation amount of W2increased, but the soil waterconsumption amount and its percentage to total water consumption amount didn't decrease,Comparing to W1treatment. However, comparing to W3treatment, the irrigation amount ofW2decreased, the soil water consumption increased. Moreover, soil water consumptionamount of W2in20-100cm layer was higher than that of W3from anthesis to maturity, butthere was no significant difference between W2and W3in total water consumption amount.2.2Effects of tillage practice and irrigation stage on the carbon metabolism of wheatUnder the same irrigation stage, the photosynthetic rate of flag leaf, Fv/Fmand SPSactivity at mid-late filling stage and dry matter accumulation amount after anthesis of SRSand RS treatment were significantly higher than those of the other treatments. Under thecondition of W2and W3, there's no significant difference between SRS and RS. But underthe condition of W0and W1, SRS treatment was higher than RS treatment, which indicatedthat SRS treatment was beneficial to delay the senescence of flag leaf and increase dry matteraccumulation amount after anthesis. The photosynthetic rate of flag leaf of SR and Rtreatment were lower at mid-late filling stage, which was unfavorable to dry matteraccumulation.Under the condition of SR and SRS treatment, there was no significant difference in photosynthetic rate of flag leaf after anthesis between W2and W1, the photosynthetic rate offlag leaf of W2was higher than that of W3at early filling stage, but was lower than that ofW3at mid-late filling stage. Dry matter translocation amount from vegetative organs to grainsin W2was higher than that in W1and W3. There was no significant difference in dry matteraccumulation amount after anthesis between W2and W1and W3. Under the condition of R,RS and P treatment, photosynthetic rate of flag leaf of W2at mid-late grain-filling stage washigher than that of W1and lower than that of W3. Dry matter translocation amount fromvegetative organs in W2was lower than that in W1and higher than that in W3. Dry matteraccumulation amount of W2after anthesis was higher than that of W1, but had no significantdifference compared with that of W3. The results showed that compared with W1treatment,under the condition of SR and SRS, W2treatment was good to increase dry mattertranslocation amount from vegetative organs to grains. Under the condition of R, RS and P,W2treatment was good to increase dry matter accumulation amount after anthesis. Incomparison with W3, W2promoted the transportation of dry matter from vegetative organs tograins.2.3Effects of tillage practice and irrigation stage on grain yield, water use efficiency andirrigation benefit of wheatUnder the condition of W0, grain yield of SRS was significantly higher than that of theother treatments. Furthermore, water use efficiency of SRS was higher than that of SR, but nosignificant difference was observed compared with other treatments. Under the condition ofirrigation, water use efficiency and irrigation benefit of SRS treatment was significantlyhigher than that of the other treatments. The grain yield of SRS and RS were higher than thatof the other treatments, but there was no significant difference between SRS and RS.Moreover, compared with the other treatments, R and SR had lower grain yield and water useefficiency. This research indicated that SRS was beneficial to increase grain yield, water useefficiency and irrigation benefit, and was the best tillage treatment in this study.Under the same tillage, grain yield, water use efficiency and irrigation benefit of W2were significantly higher than those of W1. The water use efficiency and irrigation benefit ofW2were also higher than that of W3. In addition, under the condition of SR, R and P, thegrain yield of W2was also higher than those of W3, which suggested that W2that was irrigated on10d after jointing and at anthesis was good to increase grain yield, water useefficiency and irrigation benefit. However, W3was not beneficial to high efficient utilizationof water.3Effects of tillage practice, nitrogen rate and planting density on water consumptioncharacteristics and yield formation of dry land wheatThe field experiments were carried out in Bianhe township, Bianhe village, Linzi,Shandong, during2009~2010and2010~2011wheat growing season. This area is the hilly dryland and has no condition for irrigation. The tested cultivar was Jimai22in the growingseason of2009-2010. In this experiment, four tillage treatments were designed, which wereSR treatment, SRS treatment, R treatment and RS treatment. Each tillage had three treatmentsof nitrogen rate, which were no nitrogen application (N0),90kg N hm2(N1) and150kg Nhm2(N2). The nitrogen was given as base fertilizer, and the basic seedling number was225per square meter. Under the condition of SRS treatment and nitrogen rate of150kg hm2,three planting density were designed, which were225basic seedling per square meter (D1),300basic seedling per square meter (D2) and375basic seedling per square meter (D3). Theprecipitation amount was57.9mm from sowing to pre-wintering,37.7mm frompre-wintering to reviving,35.6mm from reviving to jointing,7.9mm from jointing toanthesis,99.7mm from anthesis to maturity. During the growing season of2010~2011,Shannong16was the tested cultivar. The same treatment was designed in the sameexperimental plot in2009~2010growing season experiment. However, SRS and RStreatments were no longer subsoiling during2010~2011growth seasons. This study was toverify the effects of tillage, nitrogen rate and planting density on water consumptioncharacteristics and yield formation of dry land wheat. During2010~2011growing season, theprecipitation amount was5.0mm from sowing to pre-wintering,0.0mm from pre-winteringto reviving,20.0mm from reviving to jointing,9.5mm from jointing to anthesis and71.1mmfrom anthesis to maturity.3.1Effects of tillage practice and nitrogen rate on water consumption characteristics ofdry land wheatUnder the condition of the same nitrogen rate and225basic seedling per square meter,the soil water consumption in0-60cm soil layer from sowing to jointing and evaporation in each growing stage of SRS were lower than those of R and RS, but there was no significantdifference between SRS and SR. Moreover, water consumption from jointing to anthesis andfrom anthesis to maturity in SRS were higher than those in the other treatments. Furthermore,soil water consumption of SRS was higher than that of SR and R treatment in wheat growthseason, and was also higher than that of RS treatment in2010~2011growing season withsmall precipitation. The results suggested that SRS treatment promoted the water absorbingfrom soil by wheat, and reduced soil water diffusion to air, which was beneficial for wheat toresist drought stress.Under the condition of the same tillage practice and225basic seedling per square meter,the soil water consumption in40-200cm soil layer from anthesis to maturity, waterconsumption during different stages and their percentages to total water consumption in N2treatment were higher than those in N0and N1. Moreover, N2treatment had the highest soilwater consumption and total water consumption in the wheat growth season, and N1took thesecond place, and N0was the lowest. The results suggested that N2treatment promoted soilwater consumption of wheat, and was beneficial for growth of wheat.Comparing among the treatments with different planting density, water consumption andwater consumption percentage of D1were significantly lower than those of D2and D3fromsowing to jointing, and were significantly higher than those of D2and D3from jointing toanthesis and from anthesis to maturity. In2009~2010growing season with the precipitationamount of238.9mm, there was no significant difference in soil water consumption amongdifferent treatments. However, soil water consumption of D1was significantly higher thanthat of D2and D3in2010~2011growing season with the precipitation amount of105.6mm.This research suggested that D1treatment was beneficial to reduce water consumption atearly growth stage, and increase water consumption at late growth stage. Furthermore, D1treatment promoted water absorbing from soil by wheat under the condition of littleprecipitation.3.2Effects of tillage practice, nitrogen rate and planting density on carbon and nitrogenmetabolism of dry land wheatUnder the condition of the same nitrogen rate and225basic seedling per square meter,photosynthetic rate of flag leaf, Fv/Fm, SPS activity and SOD activity of SRS treatment were higher than those of the other treatments at mid-late grain filling stage. In addition, MDAcontent of flag leaf was lower than that of the other treatments, the dry matter accumulationamount, nitrogen accumulation amount and its contribution rate to grain were significantlyhigher than those of the other treatments after anthesis. The results showed that SRS treatmentwas good to delay the senescence of flag leaf, enhance photosynthetic production at mid-lategrain filling stage, and increase dry matter and nitrogen accumulation amount after anthesis.Under the condition of the same tillage and225basic seedling per square meter, N2treatment was favorable to increase SOD activity of flag leaf at mid-late grain filling stage,and then delay the senescence of flag leaf. Furthermore, photosynthetic rate of flag leaf atmid-late grain filling stage and dry matter accumulation after anthesis in N2treatment weresignificantly higher than those in the other treatments, which was the base for higher yield.With the nitrogen rate increasing, nitrogen accumulation amount of wheat in each growthstage increased, and nitrogen translocation amount from vegetative organs to grains andnitrogen accumulation amount after anthesis were also enhanced.Comparing among the treatments with different planting density, SOD activity of flagleaf of D1treatment was higher than that of D2and D3at mid-late grain filling stage, andMDA content of D1treatment was lower than that of D2and D3treatment, which indicatedthat D1treatment was beneficial to delay the senescence of flag leaf. Furthermore, dry matteraccumulation amount of D1was lower than that of D2and D3at pre-wintering and revivingstage, the dry matter accumulation amount of D1after anthesis and at maturity stage wassignificantly higher than that of D2and D3. The results suggested that D1treatment wasfavorable to reduce dry matter accumulation of wheat at early growth stage, but increase it atlate growth stage.3.3Effects of tillage practice, nitrogen rate and planting density on grain yield, grainprotein content and water use efficiency of dry land wheatUnder the condition of the same nitrogen rate and225basic needling per square meter,the grain yield and grain protein yield of SRS treatment were significantly higher than thoseof the other treatments. The water use efficiency of SRS treatment was higher than that of Rand RS treatment, but there was no significant difference between SRS and SR treatment.Furthermore, there's no significant difference in grain protein content between SRS and the other treatments. The results indicated that SRS treatment was favorable to increase grainyield, grain protein yield and water use efficiency, didn't reduce grain protein content, andwas the best tillage treatment in this study.Under the condition of the same tillage practice and225basic seedling per square meter,grain yield, grain protein content and grain protein yield of N2treatment were the highest,and N1took the second place, N0was the lowest. Moreover, the water use efficiency of N2was higher than that of N0treatment, but there was no significant difference between N2andN1. N2was the best nitrogen rate in this study. The results also suggested that the increase ofnitrogen rate within a certain range was beneficial to enhance grain yield, grain proteincontent and water use efficiency of dry land wheat.Comparing among the treatments with different planting density, the spike number perhectare of D1treatment was lower than that of D2and D3in2009~2010growing season withmany precipitation. However, grain number per spike,1000-grain weight, grain yield andwater use efficiency of D1treatment were higher than those of D2and D3. In2010~2011growing season with little precipitation, there were no significant difference in the spikenumber per hectare,1000-garin weight and water use efficiency among D1, D2and D3treatment, the grain number per spike, grain yield and water use efficiency of D1were higherthan those of D2and D3. The results revealed that D1treatment with the basic seedlingnumber of225per square meter was beneficial to increase grain number per spike, grain yield,and water use efficiency, was the best treatment of planting density in this study.
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