Abstract:

Based on the spring daily meteorological data of 50 meteorological stations and the development period data of 19 maize stations in Jilin province from 1981 to 2018, the spatial and temporal characteristics of the first saturating rain and the first day of temperature stable passing through 8 ℃ in spring and their effects on the timely sowing of maize were analyzed by using the method of agricultural climate statistics.The results showed that the average occurrence date of the first saturating rain generally showed a trend of early in the east and late in the west, with a difference of 20 d between the earliest and the latest.There is a difference of 35~52 days between the earliest and the latest years of the first saturating rain in the three climate zones.The difference between the earliest and the latest year when the temperature stable passes through 8 ℃ under an 80% guarantee rate is 28~31 d.The difference in spatial and temporal distribution of water and heat conditions is an important factor that causes the difference in maize planting time and seedling situation between years.The timely sowing of maize in the west is mainly affected by the presence or absence of saturating rain and the time of occurrence of saturating rain, in the middle is mainly affected by the time of occurrence of saturating rain, and in the east is mainly affected by temperature conditions.Only by combining agroclimatic and agrometeorological methods, can the suitable sowing date of the current year be better determined.

Key words: Maize, Timely sowing, The first saturating rain, The first day of temperature stable passing through 8 ℃