中国北方苹果种植需水特征及降水适宜性

Water Requirement and Precipitation Suitability of Apple Planting in Northern China

以中国北方7个苹果主产省为研究区域,基于研究区域及周边100 m范围内210个气象站1970—2019年逐日气象数据和1 km分辨率的数字高程数据,采用最小湿度法对作物系数(K_c)进行逐日估算,并利用基于样条函数插值理论的专业气象插值软件ANUSPLIN对逐日气象数据进行空间插值,计算苹果各关键生育期需水量和降水适宜度。结合苹果优势主产区地理分布确定降水适宜度阈值范围。利用相关数理统计方法明确苹果需水特征和降水适宜度时空变化特征,并对苹果全生育期降水适宜性进行评价。结果表明:苹果全年平均需水量大多数区域为500.0~800.0 mm,萌芽-幼果期、果实膨大期和着色-成熟期平均需水量占全年平均需水量的比率分别为0.186~0.282,0.392~0.562和0.159~0.282。苹果全年、萌芽-幼果期、果实膨大期和着色-成熟期降水适宜度阈值范围分别为0.49~2.07,0.25~1.70,0.54~2.25和0.46~2.65。各生育阶段降水适宜度处在阈值范围内的区域分别占85.4%,87.4%,85.6%和84.9%。苹果全生育期降水的最适宜、次适宜和不适宜区分别占研究区域的31.9%,50.6%和17.5%。

Precipitation is the main water source of apple production in northern China.Under the background of climate change,it is of great significance for apple planning to study the apple water requirement and precipitation suitability.Based on daily meteorological data and 1 km resolution digital elevation data of 210 meteorological stations in the study area and its surrounding area,the minimum humidity method is used to estimate the daily crop coefficient(K_c),and the spatial interpolation software ANUSPLIN based on spline function interpolation theory is applied.Then the water requirement and precipitation suitability of apple are calculated.According to the geographical distribution of the main planting area and percentile method,the threshold value range of precipitation suitability and optimal critical value of precipitation suitability are determined respectively.Using geographic information system(GIS)software ArcGIS,coefficient of variation,climate tendency rate and other related mathematical statistical methods,the spatial and temporal variation characteristics of apple water requirement and precipitation suitability in the study area are analyzed,and the precipitation suitability index model of apple in whole growth period is constructed to evaluate the precipitation suitability.Results show that,the average annual water requirement in most areas is 500—800 mm,accounting for 87.1%of the study area.The average water requirement in the main planting areas is basically 500—800 mm.The ratios of the average water requirement in the germination and young fruit stage,fruit expanding stage and coloring and maturity stage to the annual average water demand are 0.186—0.282,0.392—0.562 and 0.159—0.282,respectively.The threshold ranges of precipitation suitability of apple in the annual,germination and young fruit stage,fruit expanding stage and coloring and maturity stage are 0.49—2.07,0.25—1.70,0.54—2.25 and 0.46—2.65,respectively.The optimal threshold values are 0.71,0.55,0.82 and 0.56,respectively.Therefore 85.4%,87.4%,85.6%and 84.9%of the study area are suitable during each stage.The area from the most suitable critical value to the balance of water supply and demand account for 39.8%,36.9%,20.4%and 47.1%of the study area.The most suitable,sub suitable and unsuitable areas in the whole growth stage of apple account for 31.9%,50.6%and 17.5%of the study area,respectively.