| Serious drought was one of the greatest characteristics of the northwest Loess Plateau, wherehad significant differences with other districts of northern China in the climate, soil properties andproduction condition and so on. Therefore, it is necessary to extremely improve limitedprecipitation efficiency to meet the product demand by exploring and extending new cultivationpatterns. The experiment was conducted to study the differences of soil moisture content and yieldof winter and spring wheat in different mulching and straw returning methods under typical drylandecological conditions during2011~2012. The main results as followed:1The effects of mulching and straw returning methods on soil moistureThe soil moisture in0~200cm depth of straw mulching was higher than that of plastic filmmulching, plastic film mulching reused again was higher than new plastic film mulching, plasticfilm mulching before winter was higher than that mulched in spring, and winter wheat was higherthan that of spring wheat. The soil moisture of WT6and ST6both different stages and soil layerswere higher than those in CK. Mean soil moisture of WT6and ST6in0~200cm depth during thewhole growth period was higher by0.89and1.37percentage point than that in CK, respectively.The soil moisture in0~90cm depth before flowering stage under mulched treatments was higherthan that under CK, while soil moisture was lower in0~90cm depth after flowering stage and in90~200cm depth in the whole growth stages. The other mulched treatments (except ST3) of springwheat could increase soil moisture in0~90cm depth in the whole growth stages, but soil moisture in90~200cm depth was lower than that of CK from tillering to booting stages and dough stage only.The difference of soil moisture of winter and spring wheat in defferent soil layers amongtreatments showed the differences in0~90cm soil layers were larger than those in90~200cm,However, there was different in different growth stages, the maximum difference appeared fromflowering to early filling stage for winter wheat, but the largest was from tillering to booting stagesfor spring wheat. Soil water content of winter and spring wheat in0~90cm depth was higher thanthat in90~200cm before jointing stage, but after booting stage showed opposite result.The results showed that soil water content in0~200cm depth soil under wheat straw returningtreatments was higher than that of maize straw returning treatments, and soil water content of springwheat was higher than that of winter wheat. Straw returning could increase soil water content of0~200cm depth in winter and spring wheat. However, soil water content was decreased fromflowering to early filling stages for winter wheat and dough stage for spring wheat. The soilmoisture content under the combination of straw returning, plastic film mulching and compactingbefore sowing treatments in0~200cm soil layers was the highest, and higher than that of CK by0.48and1.18percentage point for winter and spring wheat, respectively. While soil water contentof W2and S2in0~200cm soil layers was lower than that of CK by0.07and0.16percentage point,respectively.The difference of soil moisture among treatments in0~20cm and120~150cm depth were thelargest for winter and spring wheat, and the maximum difference between growth stages was attillering stage. Soil moisture content of0~90cm soil depth before jointing was higher than that of90~200cm depth, but the opposite result appeared after heading stage.2The effects of mulching and straw returning methods on water consumption characteristic of wheatMulching treatments could increase water consumption amount by improving the use ofstorage water for winter and spring wheat. The total water consumption, the soil storage waterconsumption and its ratio in total water consumption were higher than those of CK by4.15%and5.05%,14.15%and35.53%,2.67and4percentage point. The results also showed waterconsumption amount of winter wheat was higher than that of spring wheat, and that of plastic filmmulching was higher than that of straw mulching.Straw returning treatments could decrease the total water consumption of winter wheat bylowering soil storage water consumption, but the results were opposite to spring wheat. The totalwater consumption, the soil storage water consumption and its ratio of total water consumptionwere lower than those of CK by2.59%,8.83%and1.89percentage point, for winter wheat, whilethat of spring wheat were higher than CK by5.29%,39.67%and and4.32percentage point. W1,W4, S1and S4in all treatments had the lowest water consumption.3The effects of mulching and straw returning methods on yield and water use efficiencyMulching treatments except ST5could increase yield and WUE of winter and spring wheat.The range of increasing of yield and WUE of plastic film mulching was larger than that of strawmulching, and that of new plastic film mulching was higher than film mulching reused again andthat of plastic film mulching before winter was higher than that in spring. The mean yield of winterand spring wheat under mulching treatments were higher than that in CK by20.04%(4.98%～28.96%) and28.33%(21.71%～37.31%), the mean WUE were higher by15.22%(8.88%～23.18%)and22.46%(18.91%～30.60%).Straw returning treatments except W6could increase yield of winter and spring wheat. Theaverage yield of straw returning was respectively higher than that in CK by13.19%(-7.37%~32.80%) and5.78%(0.08%~14.67%). W1and W4treatments were higher than that in CKby31.87%and36.07%. The average WUE of all treatments except W6of straw returning of winterwheat was higher than that in CK by16.24%(-4.91%～36.19%). However, the WUE of S1and S4treatments for spring wheat were higher than that in CK by4.22%, and other straw returningtreatments were lower by1.47%. |
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