气候变化对黄土高原苹果主产地物候期的影响

Impact of climate changes on apple’s phenophases in the main producing areas of the Loess Plateau in China

【目的】黄土高原苹果产区是我国苹果种植面积和产量最大的地区,开展气候变化对苹果物候期的影响研究,可为应对气候变化和指导该地区苹果生产提供科学依据。【方法】选取万荣、洛川和西峰作为黄土高原苹果产区代表站,利用1994—2018年各地苹果芽开放期、展叶始期、始花期、可采成熟期、叶变色末期和落叶末期物候数据,分析不同物候期及生长阶段长度的变化趋势,并利用偏最小二乘回归法,从日尺度层面,分析气温和降水变化对各物候期的影响。【结果】近25年来,黄土高原苹果主产地气候呈暖湿变化特征,受其影响,春季物候期呈提前趋势,秋季物候期呈推迟趋势,果实生长发育期和果树生长季呈延长趋势。平均气温对春秋两季物候期均有显著影响,影响时段内气温每升高1℃,春季各物候期将提前2.20~4.15 d,秋季落叶期将推迟3.58~7.77 d;降水量主要影响秋季物候期,影响时段内降水量每变化1 mm,叶变色末期将提前0.07~0.40 d,落叶末期将推迟0.12~0.55 d。各主产地间,万荣受气候变化影响最大,其次是西峰和洛川。【结论】气温对物候期的影响大于降水,且气温主要影响春季物候期,而降水主要影响秋季物候期;各物候期中,芽开放期、展叶始期和始花期主要受气温影响,叶变色末期主要受降水影响,落叶末期受温度和降水共同影响,而可采成熟期与气温和降水均无显著相关关系。

【Objective】The apple producing area of the Loess Plateau is the largest apple growing and yielding area in China,and also the most significant area affected by climate changes.This article primarily analyzes the effect of climate changes on the apple’s phenophase dates.The most important meteorological factors and the intensity of their influence on phenophase dates will be identified,which could potentially provide a theoretical basis for coping with the climate changes and guiding for fruit production in the region.【Methods】Wanrong,Luochuan and Xifeng were selected as the observed stations of the apple producing areas in the Loess Plateau,representatively,and apple’s phenology data and climate factors were collected from 3 stations during 1994—2018.Apple’s phenology data included the bud break(BO),first leaf unfolding(LU),first flowering(FF),fruit maturing(FM),end of leaf color conversion(LC)and end of leaf fall(LF),and the length of fruit growing period(FG)and tree growing season(TG),and the climate factors included daily mean temperature and precipitation.The linear fitting method was used to analyze the interannual trends of climatic factors,phenophase dates and the two different growth stage lengths,and the partial least squares regression(PLS)was applied to identify the impacts of climate changes on different phenology events affected by the daily mean temperature and precipitation.【Results】(1)Over the past 25 years,the annual average temperature of Wanrong,Luochuan and Xifeng consistently showed an upward trend.The heating degrees per 10 a were 0.86,0.01 and 0.47℃,respectively.The heating degrees per 10 a in spring(March-May)were 1.12,0.29 and 0.83℃,which were higher than the annual average temperature and other seasonal heating rates.Except for Wanrong’s decreasing trend in summer and winter,the annual and seasonal precipitation increased,with annual precipitation increasing by 13.1 mm/10 a,27.2 mm/10 a and 68.3 mm/10 a,respectively.(2)The phenophase dates in spring,autumn and the length of the two growth stages were gradually delayed,advanced and shortened from the eastern to the western region,and the spring phenophase dates showed an advance trend,the autumn phenophase dates showed a postponed trend,as well as the FG and TG showed an extended trend,generally.(3)The effect of mean temperature on the spring phenophase dates in the main apple planting areas of the Loess Plateau was significantly greater than that on the autumn dates,and it had negative effects on the spring phenophase dates and positive effects on the autumn phenophase dates.Among them,the influence period of the mean temperature on the phenophase dates in spring was concentrated from the beginning of January to the corresponding phenophase dates,a 1℃increase during this period,and BO,LU and FF would be significantly advanced by 2.59 to 3.78 d,2.20 to 3.03 d and 3.44 to 4.15 d,respectively;the effect of daily mean temperature on autumn phenophase dates was mainly reflected in LF,and the influencing periods were relatively shorter than those on spring phenophase dates,a 1℃increase in the influencing time periods,which may delay 3.58 to 7.77 days in LF.(4)The effect of precipitation on the phenophase dates of apple was significantly less than that of mean temperature,and the influence characteristics were more complex.It was found that the precipitation only affected the phenophase dates of Wanrong and Xifeng apples,which mainly affected autumn phenophase dates,and a 1mm change during the critical period may induce an advancement of 0.07 to 0.40 days in LC and delay 0.12 to 0.55 day in LF.(5)Climate changes had the greatest impact on the development of apple industry in Wanrong,followed by Xifeng and Luochuan.【Conclusion】(1)The climate of the main apple growing areas in the Loess Plateau showed a characteristics of warm and humid change.(2)Temperature had a greater impact on phenophase dates than precipitation,and temperature mainly affected the spring phenophase dates,while the precipitation mainly affected the autumn phenophase dates.(3)In each phenology,phenophase dates in BO,LU and FF were mainly affected by temperature,LC was mainly affected by precipitation,and LF was affected by temperature and precipitation,while FM had no significant correlation with any period of temperature and precipitation.(4)Among the three main apple growing areas,growers in Wanrong and Xifeng production areas should pay more attention to orchard microclimate regulation and production technology improvement to cope with the adverse effects of climate changes on industrial development.