Climate Resource Allocation And Regionalization For Regional Delay Germination Of Wine Grape In Southwest Hot-dry Valley

The southwest Hot-dry valley is one of the characteristic producing areas of wine grape in China.Excessive precipitation during the grape maturity is one of the most serious meteorological disasters,which would affect the production and quality of wine grape.How to avoid the impact from excessive precipitation had become an imminent problem to be solved.In this study,in order to avoid the rainy season according the wine grape maturity and improve the reasonable allocation of wine grape climate resources in Southwest China,we will study the allocation of climate resources for wine grape regulation.Based on the daily climate data from 1951 to 2018 and the actual growth period of wine grape from 2016 to 2018,firstly we selected Xichang typical stations in Southwest China and identified the trend of climate resources in grape year and growth period.We calculated the simulated phenology using two ways respectively as the harvest period:(1)the daily average temperature stable passing through 10?,(2)the first frost day.The date of germination was calculated by inverse calculation,refer to the average actual growth of wine grape.the growth period of delayed germination was obtained to discussion on climate resource allocation of wine grape production period regulation at Xichang.Using ANUSPLIN professional meteorological interpolation software and 1km resolution DEM data as covariates,the climatic data in dry hot valley and its surrounding 40 meteorological stations from 1971 to 2019 are interpolated,the spatial and temporal distribution and characteristics of regional wine grape agricultural climate resources were comprehensively analyzed,and the climate resource regionalization of wine grape production period adjustment in Southwest China was discussed.Combining with the dryness index,this paper analyzed the variation characteristics of the dryness during the growth period of wine grape in Hotdry valley,determined the available range of the delay germination scheme in different years,and further analyzed the characteristics of the interdecadal boundary of the production period regulation.The main research conclusion is as follows:(1)The agricultural climate resources of Xichang wine grape can meet the delayed regulation of production period.The annual average agro-climatic resources are abundant at Xichang.During the actual maturity period(August 29)to the average first frost day(December 16),the average integrated temperature of ? 10? is 1645.1?·d,the average accumulated precipitation is 277.4 mm,while the average sunshine hours are 539.7 h.There are still abundant agricultural climate resources after wine grape maturity.Therefore,it is possible to delay the adjustment of production period to avoid the excessive rain.The agricultural climate resources in the growth period can meet the needs of wine grape after the production period is delayed.The precipitation law is similar to the water demand law of wine grape,which avoids the grape diseases and pests caused by excessive precipitation in the fruit maturity period.The decline trend is not significant,and the disaster risk of rainy and low temperature during the simulated flowering period is lower than that during the actual growth period.The climate in the simulated growth period is similar to the Mediterranean ecological conditions,which provides a more suitable environment for the growth and development of wine grape.The simulated growth period of scheme 2 is slightly longer than that of scheme 1,while the number of days of scheme 1 is closer to the actual phenology.The high temperature disaster in simulated flowering period,excessive precipitation disaster in maturity period and continuous rain frequency in whole growth period by scheme 2 are lower than that of scheme 1,but the low temperature disaster in simulated flowering period is slightly more than that of scheme 1.The total number of disasters in growth period of scheme 2 is less than that of scheme 1.Overall,scheme 2 is slightly better than scheme 1.(2)The feasibility analysis of climate regulation in the region of wine grape production in dry and hot valley.The dry and hot valley area has abundant agricultural climate resources.During the period from maturity(August 31)to the average initial frost day(December 25),the average integrated temperature of ?10? is 2010.7?·d,the average precipitation is 244.9 mm,and the sunshine hours are622.3 h.Similarly,there are abundant agricultural climate resources after the actual ripening of wine grapes in dry and hot valley.Then the two delayed germination schemes of Xichang are also applied in the region.The simulation daily sequence of germination delay under the regulation of two production periods is June 11(162 DOY)and June 12(163 DOY),the number of days in the growth period decreases from north to south,the trend is consistent with the trend of heat resources,the northern heat is less,the delayed germination period is longer,the southern heat quantity is more,and the delay period of germination is shorter.The duration days were 185.5 d and 189.1 d respectively,which were close to the actual growth period days(184 days).However,some areas still have the mismatches of resources such as excessive precipitation and insufficient sunshine.When the scheme of delayed germination is applied,the actual situation of local climate resources should be combined.(3)Regional production period regulation division of wine grape in dry and hot valley.From 1971 to 2019,the dryness of wine grape in the growth period of delayed germination increased gradually from west to east.The planting limits and average planting limits in different years of the two schemes were the same.The suitable area for production period regulation was more in 1970 s and 1980 s,followed by1990 s and 2011-2019,and the least in 1990 s.In the past 50 years,stable and suitable areas were distributed in Yuanjiang River Valley and Jinshajiang River Valley,Lancang River valley was more sensitive,and Nujiang River valley was non planting area.The stable and changeable planting area of scheme 1 is slightly larger.Scheme 1 can only be used in the north and southwest of the Hot-dry valley,and scheme 2 can only be used in the northwest and northeast of the dry and hot valley.Two kinds of wine grape delayed germination schemes were used in the region,and the maximum planting area limit of wine grape delayed germination scheme was achieved.