The Statistical Analysis of Artificial Snow Augmentation Effect on Freeze Injury of the Winter Wheat

Since 1978, artificial snow augmentation by aircraft silver iodide seeding to the winter stratiform clouds have been conducted continuously along Tianshan Mountains in Northern Xinjiang, China.  The freeze injury comparison of the winter wheat was made between the 18-unseeded years and 17-seeded years.  The result has showed that the average annual freeze injury area has been decreased over 80% during seeding period in the present study.  Three main factors affected wheat freeze injury which include wheat seed improvement and wintertide temperature increase as well as artificial snow augmentation have been analysized.  The obtained results suggest that the cloud seeding is a primary factor.  Its main effect on freeze injury of winter wheat were found to be that, during critical period of December for wheat through winter, the snow cover depth was increased 2.2 centimeters and the first day of stable snow cover of five centimeters was advanced 5-7 days.