Effects On Soil Hydrothermal Changes And Yields Of Winter Wheat With Conservation Tillage In North China

Water shortage is the most important concern of grain production in North China, which causes amajor reduction in the total area of cultivated agricultural land. To overcome the scarcity of waterresources, development of appropriate crop management techniques are essential. One of these isconservation tillage, which conserves soil water content better than conventional tillage.Xushui county, Hebei province in North China was selected as a trial site from2011to2013.Minimum tillage (MT) and reduced irrigation practices were performed to determine the potentialwheat yield and to realize the possibility of low water consumption during wheat cropping period.And also the effect of tillage method carried out during wheat cropping season on soil water holdingcapacity and dynamic changes of temperature, and yield of the subsequent summer maize wereevaluated. In the study, soil water and temperature differences between MT with residue mulch andfull tillage (FT) with residue incorporated were compared, considering FT as the check. Yieldcomparison was done among MT, MT with residue mulch, MT with reduced irrigation, FT and FTwith residue incorporated. The following main conclusions were reached:1. MT with residue mulch had better soil moisture conservation than FT with residueincorporated during winter wheat growth period. Soil water content in0～80cm soil depth under MTwith residue mulch was21.1mm, which is higher than that of FT with residue incorporated, and thedifferences were primarily in0～20cm and40～80cm soil depth. Soil water content of MT withresidue mulch during seedling, tillering, hibernation, jointing, booting, grain filling and mature stageswas3.3%,2.1%,2.3%,1.2%,4.5%,2.4%and2.8%, which are higher than that of FT withresidue incorporated, respectively.2. MT with residue mulch and FT with residue incorporated revealed differences in soiltemperature during wheat hibernation and green stages of growth. MT with residue mulch showed“warming effect” and “cooling effect” during hibernation and green stages of growth, respectively.The daily soil temperature average at5cm,15cm and30cm soil depths under MT with residue mulchduring hibernation stage was1.1℃,1.1℃and0.6℃higher than that of FT with residue incorporated.Soil temperature under FT with residue incorporated during green stage increased faster than that ofMT with residue mulch. Under FT with residue incorporated, at5cm,15cm,30cm and60cm soildepth, the daily soil temperature average during vegetative stage of growth was1.9℃,1.9℃,1.2℃and0.7℃, which are higher than that of MT with residue mulch.3. MT with residue mulch produced the highest yield among all the treatments. The2-yearaverage yield obtained from MT was13.7%and6.6%, which are higher than of FT and FT withresidue incorporated, respectively. MT with residue mulch gave the highest and the most stable yields,and with20.3mm lower water content during main growth period and2.0kg.hm-2.mm-1higherwater user efficiency than that of MT with residue incorporated. MT with residue mulch also showedstable yield of winter wheat under reduced irrigation. 4. Before winter season, basic seedling and tillering were higher under MT and MT with residuemulch than that of FT and FT with residue incorporated and it was reverse during vegetative stage ofgrowth. The seedling and tillering numbers before winter under MT with residue mulch were7.5%and8.9%, which are higher than FT with residue incorporated. Similarly, the seedling and tilleringnumbers before winter of MT were3.0%and6.7%, which are higher than FT. Similar paniclenumbers were obtained from MT with residue mulch and FT with residue incorporated, and the sameresult was found between MT and FT. Before winter, the basics of seedling and tillering under MTand MT with residue mulch were not reduced.5. MT with residue mulch had a significant effect on summer corn. MT with residue mulchincreased soil water content in0～20cm and40～80cm soil depth for the subsequent corn. In0～80cm soil depth, soil water content of MT with residue mulch was5%higher than that of FT withresidue incorporated. The effect of MT with residue mulch on soil temperature of the succeeding cornwas mainly at seedling stage, which showed “cooling effect”. During seedling stage, the dailymaximum soil temperature average at5cm soil depth under MT with residue mulch was1℃lowerthan that of FT with residue incorporated, and soil temperature at15cm soil layer was0.7℃lowerthan that of FT with residue incorporated, which created a suitable environment for seedling roots,and yield for MT with residue mulch was2%higher than MT.Overall, considering the yield of winter wheat and summer corn, we found that MT with residuemulch has a good water storage and stable yield, and improved content of soil organic matter, totalnitrogen, available phosphorus and available potassium, which is the proper tillage method in thearea.