Climate Change Impact On Winter Wheat In Shaanxi Province

Climate change can impact crop production from physiology, ecological, development,distribution and so on. In order to study the impact of climate change on winter wheat inShaanxi province and provide guidance for wheat production adaption to climate change, weconducted this research in Guanzhong area and North Shaanxi area. In Guanzhong area, thestudy mainly focuses on the phenophases change and its relationship with climate change andthe change of winter wheat climate suitability from1992to2011. The research in NorthShaanxi province includes the climate change analysis of temperature, precipitation andsunshine duration during wheat growth period from1961to2001to see if it is fit for thenorthward of winter wheat there. By doing the analysis, we selected the most appropriateplace and tried to grow different cultivar of winter wheat there to see which cultivar grew best.The results show that:1) Climate suitability for winter wheat in Guanzhong area increased significantly in thepast20years, with a value0.017/10a in Guanzhong Plain and0.034/10a in Weibei Dryland.When it comes to the different climate components, temperature suitability showed anincremental tendency but without statistical significance; precipitation suitability andsunshine suitability all increased significantly. In Guanzhong plain, temperature suitabilityincreased by0.026/10a (P<0.1) and integrated suitability increased by0.034/10a（P＜0.05）during the stage from returning green to sprouting. On Weibei Dryland, precipitationsuitability increased by0.063/10a (P<0.1) and integrated suitability increased by0.026/10aduring the winter stage; the integrated suitability also increased significantly during the stagefrom sprouting to maturity, mainly due to the increase in sunshine suitability（0.046/10a, P＜0.01） and temperature suitability (0.08/10a and0.054/10a respectively, P<0.1)2) During the past20years, the average temperature, precipitation and sunshine durationshowed the same change trend in the two different ecological areas；average temperatureincreased by0.51℃/10a and0.58℃/10a respectively in Guanzhong and Weibei. In Weibeihighland, precipitation decreased by40.2㎜/10a(P＜0.05) and sunshine duration increased by312.82h/10a(P＜0.01), while in Guanzhong plain, these two factors both showed nosignificant change. For both places, the phenophases before returning green all advanced andphenophases after returning green all delayed, which makes the whole growth period shortened. Correlation analysis showed that the main factor impact wheat phenophases inGuanzhong Area is temperature. Over-wintering dates showed a positive relationship withtemperature of November and December. Returning green dates show a positiverelationship with temperature of November and December and a negative relationship withtemperature of January on Guanzhong plain, and a negative relationship with temperature ofFebruary in Weibei highland. Furthermore, for both places, sprouting date showed a negativerelationship with temperature of March and April, mature dates showed a negativerelationship with temperature from March to May. Compared with temperature, sunshineduration laid less impact on phenophases, a negative relationship was found between maturedates and sunshine duration from March to May. No significant relationship was observedbetween precipitation and phenophases.3) In the north part of Shaanxi province, negative accumulated temperature duringwintering period, mean temperature in January and≥0℃accumulated temperature in thewhole growth stage all increased significantly throughout the study period, among which thenegative accumulated temperature during wintering period increased with a rate between36.2-71.7℃d/10a, for≥0℃accumulated temperature in the whole growth stage, it was44.1-88.7℃/10a and0.32-0.61℃/10a for extreme low temperature. Accumulated temperaturebefore winter increased significantly by20.3and16.1℃d per decade respectively in Yan’anstation and Wuqi station, but leveled out in Yulin and Suide. Extreme low temperature showeda climbing tendency in the whole North Shaanxi but without significance. As for precipitation,no apparent increase or decrease tendency was observed in any station for the whole wheatgrowth stage. The precipitation ranged from44to74㎜during the before winter stage,decreased from south to north. There was almost no precipitation during winter until the endof1970s when it increased dramatically and facilitated the northward of winter wheat. Morethan65%of the precipitation happened after winter but no significant change was observed.From an overall point of view, only Yanan and Wuqi can meet the requirement of winterwheat growth. Compared with temperature and precipitation, sunshine duration is abundant inthe research area and won’t be a restriction in any part of north Shaanxi province. Taken allthe three factors into consideration, in Yanan, the climate condition has made it fit for thegrowth of northward winter wheat there. In Wuqi and Suide, though the precipitation there isclose to that in Yanan, but the mean temperature in January laid a hazard for wheat growth, sowe classified it as sub-fit area. While Yulin and Hengshan are classified as the unfit areabecause of the low negative accumulated temperature during winter, low mean temperature inJanuary and low precipitation.4) The field research in Zaoyuan district of Yanan confirmed that the yield of Jing8and Jing411can reach above200kg/667m~2in Yanan, while for Zhongyun1, the yield can evenreach as high as250kg/m~2. By improving field management the yield may reach even higher.Xinong928-21and Xinong1092are fragile to drought stress and prone to suffer from freezeinjury, so they are not fit for northward growth in Yanan. While for Zhongjiao1, as the yieldcomponents are all undesirable and it is hard to get a satisfactory yield, so it is also not fit fornorthward growth in Yanan.