Effects Of Tillage And Straw Returning On Water Consumption Characteristics In A Winter Wheat And Summer Maize Rotation System

The experiment was conducted by a combination of different tillageway and straw management. We set three tillage treatments: conventional tillage,deep tillage and subsoil tillage; two straw treatment: no straw returning and all strawreturning.Soil water consumption amount, grain yield and water use efficiency wereanalyzed by using six treatments which were conventional tillage with all strawreturning, conventional tillage with no straw returning, deep tillage with all strawreturning, deep tillage with no straw returning, subsoil tillage with all straw returning,subsoil tillage with no straw returning in a winter wheat and summer maize rotationsystem in Huang-Huai-Hai area. The results showed that:1. The results showed that deep tillage and subsoil tillage decreased soil bulkdensity, increased soil water content. The significant tillage system×straw returninginteraction decreased soil bulk density in20-40cm soil layers.Compared withconventional tillage with no straw returning, deep tillage with straw returning andsubsoil tillage with straw returning decreased soil bulk density in20-40cm depthsby8.9%and6.9%. Deep tillage or subsoil tillage combined with straw returningraised soil water content in0-100cm depths significantly. Compared withconventional tillage with no straw returning, deep tillage with straw returning andsubsoil tillage with straw returning increased soil water content in0-100cm depthsby18.0%and20.0%in the anthesis of winter wheat, increased by17.2%and20.2%in the anthesis of summer winter respectively.2. Tillage systerm and straw returning significantly or significantly effect waterconsumption, soil water reduction amount and soil evaporation. Compared withconventional tillage, deep tillage and subsoil tillage increased the water consumption of winter wheat, summer maize and the whole year, improved soil water reductionamount of0-100cm, while decreased the water consumption during fallow periods.Straw returning increased soil water reduction amount, increased soil waterconsumption amount during the growth period of winter wheat, but decreased thesoil water consumption amount during summer maize growth period and fallowperiod. Moreover, straw returning increased soil evaporation during the growthperiod of winter wheat, but decreased soil evaporation during the growth period ofsummer maize.In several tillage patterns, deep tillage with straw returning enjoyed the biggestthe water consumption rises. Compared with conventional tillage with no strawreturning, the water consumption of the whole year, winter wheat-summer maize,winter wheat, summer maize of deep tillage with straw returning increased by3.3%,4.2%,4.4%and4.1%, fallow periods reduced by7.0%. Deep tillage (subsoil tillage)and straw returning were conducive to increase soil water storage in the formergrowth stage of winter wheat and summer maize, improve soil water absorption inthe later the growth stage of winter wheat and summer maize. Tillage system andstraw returning mainly affected soil water reduction amount below20cm soil layers.Deep tillage (subsoil tillage) straw returning decreased soil evaporation during thegrowth period of summer maize. Deep tillage and straw returning increased, butsubsoil tillage decreased the soil evaporation during the growth period of winterwheat.3. The results showed that deep tillage or subsoil tillage combined with strawreturning raised relative water content, enhanced net photosynthetic rate (Pn) andtranspiration rate (Tr) of leaves, increased bleeding sap in stalk, thus promoted drymatter accumulation of winter wheat and summer maize. Compared withconventional tillage with no straw returning, water saturation deficient in leaves ofdeep tillage with straw returning decreased by18.9%and33.3%, Pn increased by29.8%and45.7%, Tr increased by19.4%and28.1%, bleeding sap in stalk increasedby19.0%and34.7%in the anthesis of winter wheat and summer winter respectively;water saturation deficient in leaves of subsoil tillage with straw returning decreasedby19.2%and32.8%, Pn increased by33.3%and46.1%, Tr increased by22.6%and31.3%, bleeding sap in stalk increased by23.2%and35.7%in the anthesis of winterwheat and summer winter respectively. Compared with conventional tillage with nostraw returning, dry matter accumulation of deep tillage with straw returning increased by20.7%and17.8%in the anthesis of winter wheat and summer winterrespectively, dry matter accumulation of subsoil tillage with straw returningincreased by26.5%and20.2%.4. There was significant tillage system×straw returning interaction in grainyield and water use efficiency of winter wheat and summer maize.Compared withconventional tillage with no straw returning, the grain yield of deep tillage withstraw returning and subsoil tillage with straw returning increased by18.0%and19.3%, the water use efficiency increased by15.9%and15.1%. Moreover, there wasno significant difference in grain yield and water use efficiency between deep tillagewith straw returning and subsoil tillage with straw returning. Therefore, werecommend that deep tillage or subsoil tillage with straw returning was the mostappropriate tillage practice in Huang-Huai-Hai area.