Study Of The Influrence Of Late Frost Damage On Grape Vine In North Xinjiang In 2008

The late frost had a great influence on agriculture production in North Xinjiang from April 18, 2008 to April 21, 2008. This research focused on wine-making vineyard of the Manas River Valley, the frost damage of grape vine with different varieties, time of bud-break, time of de-hilling and length of bearing shoots were investigated. The meteorological characteristics and harmful mechanism of late frost were analyzed according to 20 years meteorological data from 1991 to 2009, the results showed that:1. The tender shoots of different varieties had nearly same endurance upon low temperature, while the tender shoots in different growth period had great difference in endurance.2. Rain, snow and frost weather occurred in large range resulted in great loss upon grape vines in all parts of North Xinjiang. A yield reduction by 60% was occurred in No.222 Farm near the desert in 2008.3. There were some differences among varieties in rate of yield reduction, which mainly associated with different bearing habit and prunning method of different varieties. Increasing buds on bearing shoots was benefit to yield recovery.4. There were siginificant different among vines de-hilled in different date in terms of frost damage. The frost damage was more and lighter with the delay of the date of de-hilling. The lighteset damage was associated with the date when late frost was just gone (April 21), too late de-hilling increase the damage of vine.5. The degree of frost damage was determined by the lowest temperature and sustained time of low temperature. The frost occurred this year brought nearly same degree of damage upon different vineyards, site condition such as chained vineyards, vineyard near reservoir, vineyard near shelterbelt ,vineyard near residential area, even vineyards with irrigation and smoking protection measure.6. The frost was prone to occure before April 15, and the probability of occurrence of frost damage was reduced with the temperature rose followed by time gone, but once occurred, the heavy harmfulness probably increased. On April 19 the frost-free day(lowest temperature≧0℃) probability came up to 90%, on April 15 the frost-free day(lowest temperature≧0℃) probability came up to 80%.7. The date of de-hilling should not precede April 10 in local area, the date of de-hilling for cabernet sauvignon can associated with≧10℃accumulated temperature (150℃) .