| 1Effects of soil moisture on water consumption characteristics and yield in differentwheat cultivarsThe experiment was carried out in2009~2010wheat growing season using Small-spiketype cultivars: Jimai22(J22), Shannong15(S15); Large-spike type cultivars: Zhouyuan9369(ZY9369), Shannong8355(S8355), Tai9818(T9818), Weimai8(WM8). Four irrigationtreatments were designed in the experiment:(1) no irrigation (W0),75%of relative soilmoisture content in0~140cm soil layers at jointing and70%at anthesis (W1),75%on on8dafter jointing+70%on8d after anthesis(W2),75%on8d after jointing+75%on8d afteranthesis(W3). Effects of irrigation stage and soil moisture on water consumptioncharacteristics and yield in different wheat cultivars were studied using randomized blockdesign.1.1Effects of soil moisture on water consumption characteristics in different wheatcultivars1.1.1Differences of water consumption characteristics in different wheat cultivarsThe total amount of water consumption of J22was lower than T9818, there were nosignificant difference in the ratio of the amount of soil water consumption to total amount ofwater consumption under the condition without irrigation for other cultivars. J22had thehighest water consumption amount from anthesis to maturity and its water consumptionpercentage, T9818took the second place, while S15was the lowest. The total amount ofwater consumption of J22was the highest, the ratio of the amount of irrigation and soil waterconsumption to total amount of water consumption under the condition of irrigation in J22 were higher, while ZY9369had lower total amount of water consumption and the ratio of theamount of soil water consumption to total amount of water consumption. The results indicatedthat J22had higher absorption and utilization of soil water under the same water treatment;J22had higher water consumption amount from anthesis to maturity, which was beneficial tomeet the photosynthetic and transpiration water requirement during the yield fromation stage.1.1.2Effects of soil moisture on water consumption characteristicsThe total amount of water consumption in W0treatment was the lowest, but the ratio of theamount of soil water consumption to total amount of water consumption in W0treatment wasthe highest, while that in W3treatment was the lowest, the results indicated that no irrigationwater improved the absorption and utilization from soil water. Compared among the irrigationtreatments, W3treatment had the highest total amount of water consumption, irrigationamount and the ratio to total amount of water consumption, but the ratio of the amount of soilwater consumption to total amount of water consumption was lower; W3treatment also hadthe highest amount of water consumption and the water consumption percentage duringanthesis to maturity, while those in W1treatment were the lowest. The results indicated thatthe irrigation amount and total amount of water consumption increased with delaying thejointing and blossom irrigation, but the consumption of soil water decreased. The total amountof water consumption further increased with the blossom irrigation level increased, the soilwater consumption further decreased, however, the amount of water consumption and itswater consumption percentage during anthesis to maturity increased, which was beneficial tomeet the photosynthetic and transpiration water requirement during the yield fromation stage.1.2Effects of soil moisture on root activity and osmotic adjustment ability of the flag leafin different wheat cultivars1.2.1Differences of root activity and osmotic adjustment ability of the flag leaf indifferent wheat cultivarsJ22had higher root activity at jointing and anthesis and lower root activity at the later grainfilling stage in W0and W1treatments. S15had higher root activity at the later grain fillingstage, while T9818took the second place. J22had higher root activity at the grain filling stagein W2and W3treatments, which was beneficial to the absorption of water and nutrients forwheat, while that in WM8was the lowest. Under the same condition of soil moisture, J22,ZY9369and WM8had higher relative water content of flag leaves, flag leaf water potential and osmotic potential at the beginning and middle grain filling stage; S8355had higherosmotic adjustment saturation capacity at the later grain filling stage, while that in S15wasthe lowest. The results indicated that under different conditions of irrigation, J22had higherroot activity and osmotic adjustment saturation capacity at the beginning and middle grainfilling stages, which was beneficial to keep higher root activity with delaying the jointing andblossom irrigation. WM8had higher osmotic adjustment saturation capacity at the beginningand middle grain filling stage, but its root activity was lower, which was disadvantage to theabsorption of water and nutrients, and it was the reason for the lower grain yield and wateruse efficiency in WM8.1.2.2Effects of soil moisture on root activity and osmotic adjustment ability of the flagleaf in wheatThe root activity in W3treatment at the later grain filling stage was higher, which wasbeneficial to the absorption of water and nutrients; the relative water content of flag leaves,the flag leaf water potential and the osmotic potential in W3treatment were higher than thosein other treatments, W2treatment took the second place, while W0treatment were the lowest.The results indicated that delaying the jointing and blossom irrigation would improve the rootactivity and osmotic adjustment saturation capacity at the later grain filling stage. However, itwould further improve the root activity and osmotic adjustment saturation capacity at the latergrain filling stage further increased, with the blossom irrigation level increased to75%.1.3Effects of soil moisture on photosynthetic carbon metabolism in different wheatcultivars1.3.1Differences of photosynthetic carbon metabolism in different wheat cultivarsS8355had higher photosynthetic rate, Fv/Fm, ΦPSII, sucrose content and SPS activity offlag leaf after anthesis, ZY9369had lower photosynthetic rate, sucrose content and SPSactivity of flag leaf, while those of J22and WM8were the middle. S8355had higher drymatter accumulation amount, assimilator accumulation amount after anthesis and itscontribution ratio to grain, those of ZY9369were lower, while those of J22and WM8werethe middle. The results indicated that higher photosynthetic rate of flag leaf at the middle andlater grain filling stage, which was beneficial to increase dry matter accumulation andtranslocation amount after anthesis, was the reason for S8355gained higher grain weight. ZY9369had lower grain weight, while that of J22and WM8was the middle.1.3.2Effects of soil moisture on photosynthetic carbon metabolism in wheatW3treatment had the highest photosynthetic rate, Fv/Fm, ΦPSII, sucrose content and SPSactivity of flag leaf, and dry matter accumulation amount at maturity, dry matter accumulationand translocation amount after anthesis, and the grain filling rate, those of W2treatment tookthe second place, while those of W0were the lowest. The results indicated that delaying thejointing and blossom irrigation was beneficial to keep higher photosynthetic rate of flag leafat the middle and later grain filling stage; Increasing the blossom irrigation level to75%wasbeneficial to further improve the photosynthetic capacity, and to increase the dry matteraccumulation amount in grain.1.4Effects of soil moisture on grain yield, quality and water use efficiency in differentwheat cultivars1.4.2Differences of grain yield, quality and water use efficiency in different wheatcultivarsUnder the same condition of irrigation, J22had the highest grain yield, that of S15andS8355took the second place; J22, S15and S8355had higher water use efficiency andirrigation benefit. ZY9369and WM8had lower grain yield, water use efficiency andirrigation benefit. The results indicated that J22, S15and S8355were the wheat cultivars withhigh grain yield and water use efficiency.1.4.1Effects of soil moisture on grain yield, quality and water use efficiency in wheatThe grain yield in W3treatment was higher than those in W1and W2treatments, W3treatment had lower water use efficiency for S15and WM8, respectively; there were nosignificant difference among irrigation treatments for other wheat cultivars. W1treatment hadthe highest irrigation water use efficiency, while W2treatment took the second place. The wetgluten content, dough development time and dough stability time in W0treatment were thehighest, W1and W2treatments took the second place and there was no significant differencebetween W1and W2. The results indicated that irrigation at jointing and anthesis would gainhigher grain yield and water use efficiency, and better grain quality; increasing furtherblossom irrigation level, the grain yield and water use efficiency further increased for somewheat cultivars, but the wet gluten content, dough development time, dough stability time and grain quality decreased.2Effects of tillage and soil moisture on water consumption characteristics and yieldThe field fixed position experiment was conducted with wheat cultivar Jimai22in Shiwangvillage (35.41°N,116.41°E), Yanzhou, Shandong, China. Five tillage practices which wereplowing tillage (C), strip rotary tillage (M), strip rotary tillage after subsoiling (MS), rotarytillage (X) and rotary tillage after subsoiling (XS) respectively, were designed and conductedon the same experimental plots during2007~2011growth seasons. However, MS and XSwere no longer subsoiling during2008~2009and2009~2010wheat growth seasons, whilehalf were subsoiling and half were no longer subsoiling in2010~2011wheat growth seasons.So seven tillages practices were conducted: plowing tillage (C), strip rotary tillage (M), thefirst year of subsoiling+four-year strip rotary tillage(MS), the first year of subsoiling+threeyear strip rotary tillage and the forth year of subsoiling+strip rotary tillage(MS’), rotarytillage(X), the first year of subsoiling+four-year rotary tillage(XS), the first year ofsubsoiling+three year rotary tillage and the forth year of subsoiling+rotary tillage(XS’).This paper analyzes the results of the experiment in2010to2011, in order to verify the effectsof the subsoiling in the first year on grain yield and water use efficiency. The soil moisturetreatments were designed as no irrigation (W0),65%of relative soil moisture content in0~140cm soil layers at jointing and70%at anthesis (W1);65%at jointing and75%atanthesis (W2);70%at jointing and70%at anthesis (W3);70%at jointing and75%at anthesis(W4).2.1Effects of tillage and soil moisture on water consumption characteristics2.1.1Effects of tillage on water consumption characteristicsThe total amount of water consumption, soil water consumption amount and its percentageto total water consumption amount in MS’ and MS treatments under the condition withoutirrigation were higher than those in M treatment, the discipline was the same while comparingamong XS’, XS and X treatments. Under the condition of irrigation, the total waterconsumption amount, irrigation amount and its percentage to total water consumption amountand soil water consumption amount in MS’ and MS treatments were higher than those in Mtreatment. Under the same condition of irrigation, the soil water consumption amount of20~180cm soil layers, the water consumption amount and its water consumption percentage from jointing to anthesis and anthesis to maturity in MS’ were higher than those in Mtreatment; the soil water consumption amount of20~140cm soil layers, the waterconsumption amount and its water consumption percentage from jointing to anthesis andanthesis to maturity in XS’ treatment were higher than those in X treatment; the soil waterconsumption amount of20~120cm soil layers, the water consumption amount and its waterconsumption percentage from jointing to anthesis and anthesis to maturity in MS treatmentwere higher than those in M treatment; XS treatment was higher than X treatment too. Theresults indicated that subsoiling promoted the use of deep soil water for wheat, increased theamount of soil water consumption, and improved the water consumption during the yieldfromation stage, besides, it improved the absorption and utilization of irrigation water. Theaftereffect of once subsoiling can continue until the fourth year, but the effect is significantlyreduced.2.1.2Effects of soil moisture on water consumption characteristicsUnder the same condition of tillage, the total amount of water consumption, the waterconsumption amount and its water consumption percentage from jointing to anthesis of W0treatment was the lowest, however it gained the highest percentage of soil water consumptionamount to total water consumption amount and the water consumption amount and its waterconsumption percentage from sowing to jointing. The total water consumption amount,irrigation amount, and its water consumption percentage to total water consumption amountin W3treatment were lower than those in W2and W4treatments. The percentage of soilwater consumption to total water consumption amount in W1and W3treatments were higherthan that in W2and W4treatments. The water consumption amount and its waterconsumption percentage from anthesis to maturity showed that W2treatment was higher thanW1treatment, W4treatment was higher than W3treatment. The results indicated thatdecreasing supplementary irrigation level at jointing and increasing the blossom irrigationlevel will increase the amount of irrigation water which can increase irrigation amount anddecrease the consumption of water from soil water for wheat. The water consumption amountand its water consumption percentage from anthesis to maturity increased with the irrigationlevel at anthesis increased, which was beneficial to meet the photosynthetic and transpirationwater requirement during the yield fromation stage. 2.2Effects of tillage practices on soil microbial and soil enzyme activityThe microbial biomass C and active microbial biomass and soil respiration in XS’ treatmentwere the highest, MS’ treatment took the second place. The soil unease activity in MS’ andXS’ treatments were higher than those in C, X and M treatments during jointing, anthesis andmaturity; the soil sucrose enzyme activity in MS’ and XS’ treatments were lower than that inC treatment at jointing and anthesis, but higher than that in X and M treatments; the soilsucrose enzyme activity in MS’ and XS’ treatments was higher than those in C, X and Mtreatments at maturity. The results indicated that subsoiling increased the microbial biomass Cand active microbial biomass, soil respiration, soil unease activity and soil sucrose enzymeactivity, which was beneficial to the transfromation of soil carbon and nitrogen.2.3Effects of tillage and soil moisture on root activity and water potential of flag leaf2.3.1Effects of tillage on root activity and water potential of flag leafThe root activity at each growth stage, water potential of flag leaf on20days and30daysafter anthesis in MS’ and XS’ treatments were higher than those in M and X treatments. Theroot activity in MS treatment at jointing, anthesis and middle grain filling stage were higherthan those in M treatment, XS treatment was higher than X treatment. The results indicatedthat subsoiling improved the root activity, which was beneficial to the absorption of water andnutrients for wheat; subsoiling also increased the water potential of flag leaf during the middleand later grain filling stage, which improved the status of water of flag leaf, and wasbeneficial to the maintenance of photosynthesis of flag leaf. The aftereffect of once subsoilingcan continue until the fourth year, but the effect is significantly reduced.2.3.2Effects of soil moisture on root activity and water potential of flag leafIn various tillage conditions, the root activity in W0treatment was the highest duringanthesis, but it gradually decreased with the increase of irrigation amount at jointing. Theroot activity in the treatment that70%of relative soil moisture content in0~140cm soillayers at jointing and70%at anthesis was the highest, which was beneficial to the absorptionof water and nutrients for wheat; however, the root activity decreased during the middle andlater grain filling with the irrigation level increased to75%at anthesis. The water potential offlag leaf after anthesis in the condition of irrigation was higher than that in the conditionwithout irrigation, the water potential of flag leaf on20days and30days after anthesis in W2 and W4treatments were higher than those in W1and W3treatments. The results indicatedthat it was beneficial to maintain a higher water potential of flag leaf during the middle andlater grain filling stage in the condition of irrigation at jointing and anthesis, especially toincrease the irrigation level at anthesis.2.4Effects of tillage and soil moisture on photosynthetic carbon metabolism2.4.1Effects of tillage on photosynthetic carbon metabolismXS’ and MS’ treatments gained the highest photosynthetic rate and ΦPSII of flag leaf at themiddle and later grain filling stage, they also gained the highest sucrose content and the SPSactivity after anthesis; the Fv/Fm of flag leaf in XS’ and MS’ treatments were higher thanthose in X and M treatmensts. The dry matter accumulation amount, assimilate accumulationamount after anthesis and its contribution ratio to grain in XS’ and MS’ treatments werehigher than those in the other treatments. The sucrose content and the SPS activity afteranthesis, dry matter accumulation amount, assimilate accumulation amount after anthesis andits contribution ratio to grain in XS’ and MS’ treatments were higher than those in X and Mtreatments. The results indicated that subsoiling improved the ability of photosynthetic at themiddle and later grain filling stage, which had a favorable impact on dry matter accumulationand translocation after anthesis; the aftereffect of once subsoiling can continue until the fourthyear.2.4.2Effects of soil moisture on photosynthetic carbon metabolismUnder the same condition of tillage, W3treatment had the highest sucrose content, SPSactivity after anthesis, and assimilate accumulation amount at maturity, W1and W4treatmenttook the second place, while those in W0treatment was the lowest. The assimilateaccumulation amount and its contribution ratio to grain in W3treatment was higher than thosein W2and W4treatments, the grain amylopetin content and total starch content in grain ofW3treatment were higher. The results indicated that W3treatment improved the sucrosecontent at the middle and later grain filling stage, which had a favorable impact on dry matteraccumulation and translocation after anthesis and the amylopetin content and total starchcontent in grain. However, the dry matter accumulation amount in grain decreaed as too muchirrigation applied at anthesis.2.5Effects of tillage and soil moisture on grain yield and water use efficiency 2.5.1Effects of tillage on grain yield and water use efficiencyUnder the same condition of irrigation, XS’ and MS’ treatments had the highest grain yieldand water use efficiency, those was no significant difference between XS’ and MS’ treatment.The grain yield, water use efficiency and irrigation benefit in XS and MS treatments werehigher than X and M treatments; the irrigation benefit in MS’ treatment was the highest, thatin XS’ treatment took the second place, while that in M treatment was the lowest. The resultsindicated that under the same condition of irrigation, subsoiling improved the grain yield,water use efficiency and irrigation benefit; the aftereffect of once subsoiling can continueuntil the fourth year.2.5.2Effects of soil moisture on grain yield and water use efficiencyUnder the condition of C treatment, the highest irrigation benefit in W1treatment was thehighest, that in W3treatment took the second place; in other condition of tillage, the irrigationbenefit in W3treatment was the highest. Under the condition of XS’ and MS’ treatments, thewater use efficiency in W4treatment was the lowest, there were no significant differenceamount W0, W1, W2and W3treatments; under the condition of the other tillage practices, thehighest water use efficiency in W0treatment was the highest, that in W1and W3treatmentstook the second place, while that in W2and W4treatments was the lowest. Under the samecondition of tillage, the grain yield in W3treatment was the highest, that in W1and W4treatments took the second place, there was no significant difference between W1and W4treatments, while that in W2treatment was the lowest. The results indicated that W3treatmentin which the relative soil moisture content of0~140cm soil layers at jointing and anthesiswere70%and70%, respectively, had higher grain yield, water use efficiency and irrigationbenefit; and the grain yield and water use efficiency decreased as too much irrigation appliedat anthesis.As far as water-saving and high-yield were concerned in this experiment, the mostappropriate treatment for recommendation was the one under the strip rotary tillage aftersubsoiling, in which the relative soil moisture content of0~140cm soil layers at jointing andanthesis were70%and70%, respectively. |
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