The Spatial-temporal Variation Of Water Supply Demand Balance And Its Relationship With Apple Yield In Shandong Province

Water plays an important role in the growth and development of apple trees.In Shandong Province,which is a major apple production province,it is important to study the water supply and demand in apple orchards and to analyze the spatial and temporal distribution characteristics of precipitation,evapotranspirationand and water budget in different growth stages of apple orchards,so as to better realize the scientific management of water in apple orchards.In this paper,106 counties and cities with relatively high apple yield in Shandong Province were studied.The meteorological data collected in the relevant counties and cities from 1971 to 2017 were used to calculate evapotranspiration and water budget.According to the growth habits of fruit trees,different growth stages were divided.The spatial distribution of water index in different stages was mapped.At the same time,three representative counties and cities in typical areas of apple production were selected according to the yield distribution of apple orchards.The correlation analysis on time dimension and the correlation test between the relevant water index and the yield of the orchard in that year were carried out.(1)The apple yield per unit area in Shandong Province showed a steady upward trend,and the spatial distribution showed a decreasing trend from coastal to inland and from east to west.The apple yield of in Jiaodong Peninsula was more prominent,followed by that in Luzhang Mountainous District,and in Luxi Plain.(2)The spatial distribution of annual precipitation in Shandong apple production areas showed a decreasing trend from southeast to northwest,or coastal to inland,and the annual evapotranspiration special distribution also revealed a increasing trend from southeast to northwest.The annual water supply in Shandong orchards was in a deficit state as a whole,and the distribution showed a trend of increasing deficit from southeast to northwest.At different growth stages of apple trees,for the spatial distribution of precipitation in orchards,there were significant differences existed between autumn shoot stop stages and other growth stages.The orchards evapotranspiration increased from southeast to northwest during spring shoot growth and leaf curtain formation stages,and the water deficit of orchards increased from southeast to northwest at the same growth stage.(3)It was found for time analysis of typical counties and cities that annual precipitation in Qixia was decreased by 12.84mm/10 a while Juye increased by 6.65mm/10 a and Yiyuan by0.14mm/10 a,and annual evapotranspiration in Qixia was remarkably lower than that in Juye and Yiyuan.The decline trend in Qixia was the most significant,reaching 27.06mm/10 a,while that in Juye was the weakest,reaching 0.52mm/10 a from 1970 to 2017.(4)At the different growth stages,the precipitation of orchards in the leaf curtain formation stage was more than that in other stages,and the water was in surplus,the evapotranspiration of orchards in the spring shoot growth stages was more than that in other stages.In addition,the water in orchards was in deficit,but the relative change was stable and the fluctuation was lesser in the dormancy stages.(5)The catastrophic comparison of typical counties and cities stated that the precipitation was decreased significantly in Qixia and Yiyuan,especially in spring and autumn shoot growth periods,but slightly in Juye.The orchard evapotranspiration was reduced significantly in the spring shoot growth stages,leaf curtain formation and autumn shoot growth stages,and water deficit was encouraged notably for spring shoot growth stages in Yiyuan.By contrast,the water deficit of Qixia was attenuated obviously during the period of leaf curtain formation and autumn shoot growth stages.(6)Among the changes of orchard water index in different growth stages of fruit trees,the annual precipitation of orchard was closely correlated with orchard yield.The correlated coefficients between Qixia,Yiyuan,Juye and orchard yield were 0.7288,0.5954 and 0.6464,respectively.Compared with different growth stages,the change of water index in spring shoot growth stage and the yield of orchard have a closer relationship,and the correlation coefficient of precipitation and yield in the corresponding growth stages of Qixia,Yiyuan and Juye were extremely related,presenting as 0.5012,0.4606 and 0.4111,respectively.These findings suggested that the growth period of spring shoots may be the key period,which exhibits a major relevance with the yield of orchards.