Different Responses Of Winter Wheat And Summer Maize Yields To The Water Saving Management Practices In A Sub-humid Region Of Northwest China

The greatest fear of global climate changes is drought and water is the most importantfactor influencing crop growth. The climatic changes with high atmospheric evaporativedemand have put the farming in unpredictable risk. Looking for avoid the water stress and toincrease the productivity at arid and semiarid regions generally adopt the use of waterharvesting techniques, principally the mulch. North Chinese Plain (NCP), and GuanzhongPlain in central Shaanxi, is country’s major region for winter wheat and summer maize doublecrop production. However, long-term precipitation in the area ranges from400to650mmannually with65%falling during maize growing season. But during the growing season ofwinter wheat, precipitation could only meet up25to40%of the requirement of crop.Therefore, to develop better soil-water management practices, A field experiment to study thedifferent responses of winter wheat and summer maize yield to water saving and nutrientmanagement practices was conducted at the south edge of Loess Plateau, Yangling, Shaanxi,China.The experimental design was split plot, with four water management practices i.e. plasticmulch ridge and straw mulch furrow combined with deficit irrigation (RF+DI), straw mulchcombined with deficit irrigation (SM+DI), deficit irrigation (DI), and conventional floodirrigation (CFI) as main plot treatments, and nitrogen fertilizer rate i.e.(0,120and240kg ha-1)as subplot treatments. Soil temperature and moisture during the crop growth were monitored.Grain yield and growth components of crops were also measured during the study.Results indicated that winter wheat yields in the RF+DI treatment were slightly more thanthose in the SM+DI, DI and the CFI treatments. Water saving management practices had asignificant effect on maize yields. Over the five years study, total maize yield in the RF+DItreatment was25.23%more than in the DI treatment, and26.58%more than in the CFItreatment. Compared to the CFI and DI treatments, SM+DI treatment produced19.04%and17.55%more maize yield, respectively. The growth component’s data for maize crop hadalso significant difference among treatments. In2012, stem production in the RF+DItreatment was27.8%and21.5%greater than those in the DI and CFI treatments, respectively.SM+DI increased stem yield by1.3times than in DI and1.2times than in the CFI treatments. Leaves production were also significantly higher in the water saving treatment compared toCFI or DI treatment. RF+DI treatment found to increased leaves production by20and14%when compared with DI and CFI, respectively. There was no significant difference in maize’stassel, cob, and husk yields among the water saving and conventional treatments. In2013, allgrowth component of maize were remarkably different among treatments. This improvementin yields was due to favorable condition made by water saving practices.Soil water content in RF+DI and SM+DI treatments at20cm soil profile wassignificantly higher than those of CFI or DI treatments. Compared with DI treatment, theaverage soil water storage (0-20cm) over2012-2013winter wheat season at different growthstages was significantly increased with RF+DI, SM+DI, and CFI by11.5%,19.6%and13.6%, respectively. At post harvest time of wheat in2013, water saving management practiceshad no significant effect on soil moisture stored in the0-200cm neither at top nor deep soilprofiles. But the difference in soil water content was significant among treatment at top soillayers after harvesting the maize in2012.Soil temperature at10cm depth was also significantly affected by mulch managementpractices. The soil temperature was highest with RF+DI and lowest with CFI treatment duringcold winter and it was consistently higher with CFI and low with RF+DI and SM+DI in hotsummer at0-10cm soil depth. During2011-2012wheat growing season, plastic mulch ridgeaccumulated high temperature (849DDs) followed by straw mulched furrow in RF+DItreatment (780DDs), while the lowest heat was accumulated in the SM+DI treatment(741DDs). The low soil temperature in SM+DI plots delayed winter wheat growth stages anddevelopment, thus reduced grain yield compared with RF+DI treatment. In2013, duringsummer maize growing season, plastic mulched ridge in the RF+DI treatment wasaccumulated the greater soil temperature of948.2DDsoil, followed by SM+DI and strawmulched furrow in the RF+DI treatment. The positive effects RF+DI system on both wheatand maize yields in our study could be explained by harmonizing soil moisture andtemperature by this treatment.The results of META-analysis in our study, which is the summary of48differentresearch’s works, have also proved that the difference in the effect size of crops yields tomulch practices commonly related to their types and climate conditions. Both positive and negative responses of yield were found in all the areas classified by regional precipitation ortemperature.