Abstract:

On the basis of the meteorologic data observed by 4 meteorological stations in southern Hebei from 1962 to 2009, the variation features of agricultural climate resources during the growth period before overwintering was studied by applying the methods of climatic trend rate, wavelet analysis and M-K methods. The results showed that the first day of winter wheat overwintering period was postponed and climate heat resources was more abundant in recent fifty years. The first day of winter wheat overwintering period and climate heat resources were also existed abrupt change over 1987. Sunshine hours and aridity-wetness homogenized index during the growth period before winter did not change significantly and there were no abrupt changes. The first day of winter wheat overwintering period had mainly the interannual oscillation periods of 6-7 years and 12-16 years. The accumulate temperature of ≥0℃ before overwintering had mainly the interannual oscillation periods of 6-8 years from 1962 to 1988 and that of 8-10 years from 1989-2009. Multi-scale variations existed in sunshine hours and 10-12 years variation period was identified over the past twenty years. Aridity-wetness homogenized index during the growth period before winter had mainly the interannual oscillation periods of 4-6 years and 14-16 years. The results indicated that climate heat resources and the first day of winter wheat overwintering period changed obviously. Appropriate readjustment should be made by full consideration of.climate change in recent ten years.Aridity-wetness homogenized index showed the wetting trend and the probability of freezing damage was little.With the interannual changes of dry and wet , irrigation before wintering was the important measures that reduced risks of the wheat frozen injury.