关键词: 表达, 表达

Abstract: To serve for disaster prevention and mitigation and ensure grain production safety, the paper adopted atmospheric precipitation data in three cities of Chaoyang, Fuxin and Huludao from 1953 to 2013, and applied methods of variation trend, variability rate, standard deviation, crop drought index etc., to analyze the ample-deficient relation of precipitation and water requirement and drought frequency in West Liaoning area during maize production period. The result shows that: from 1953 to 2013, the precipitation has shown an increasing trend during maize seeding to elongation stage, a trend of significant decrease during elongation stage to mature period. In recent 10 a, the precipitation was reduced 62.0 mm during flowering stage and 64.2 mm in all growth period. Water requirement of maize in all growth period was bigger than average rainfall while in the 61 a, amply rainfall accounted for 47.5% and deficient rainfall accounted for 52.5%. West Liaoning area in maize all growth period belonged to semi-arid climatic zone with 37.7% of the time in a year was semi-arid.Among which, drought frequency during seeding to emergence period was the highest (55.7%), followed by the elongation to flowering period (34.4%); and drought frequency was the lowest during flowering to mature period and emergency to elongation period which was 16.4% and 13.1%, respectively . The recent 10a crop drought index has been upgraded from semi-arid to arid; the drought frequency has obviously increased. Under the situation of growing agricultural arid tendency, adjustment of crop structure should be speeded up and groundwater resources should be made full use to complement insufficient rainfall so as to reduce drought damages.