石家庄平原区降水变化与农业生产的适应性研究

Research on Adaptability of Agricultural Production to Precipitation Change in Shijiazhuang Plain

通过对石家庄平原区降水特征及主要耗水型农作物需水规律的分析,揭示了农作物生长缺水量及缺水时段年内分布规律。结果表明,石家庄平原区降水量较小,降水集中,与农业生产之间表现出了明显的不适应性;自然降水条件下,丰水年、平水年、枯水年冬小麦-夏玉米一年两熟制种植模式缺水量分别达8.3、10.3和12.6亿m3,蔬菜缺水量分别达1.2、1.2和1.3亿m3;丰水年、平水年、枯水年时,缺水时段均主要集中在3～5月份,其缺水量分别占年缺水总量的66.8%、59.9%和57.3%。虽然从20世纪70年代开始,3～5月份降水量呈增加趋势,但增加有限,远不能抵消作物生长缺水量,仍需大量开采地下水补充灌溉。

This paper firstly analyzed precipitation characteristics and crop water requirement regulation.Then it calculated quantity of crop water shortage and revealed the regulation of water shortage in different months.Finally,based on variation trend of precipitation,it revealed the impact of precipitation change on crop water shortage.The results showed that mean precipitation of recent years was small and it was concentrated in the flood season,which did not adapt to agricultural production.In wet years,water shortage of winter wheat and summer maize rotation system reached 8.3×10^8 m^3,and it was 10.3×10^8 m^3,12.6×10^8 m^3 in normal years and dry years instead.For vegetables,water shortage achieved 1.2×10^8 m^3 in wet years.In normal years and dry years,it respectively reached 1.2×10^8 m^3 and 1.3×10^8 m^3.Both in wet years and normal or dry years,water shortage period was concentrated in March,April and May.The quantity of water shortage in this period accounted for 66.8% of annual total water shortage in wet years,and the ratio was 59.9% in normal years,57.3% in dry years.Although precipitation in this period of March to May increased from 1970s,the increase was very limited,far less than quantity of crop water shortage.So in order to guarantee crop water requirement,it was still necessary to exploit a lot of groundwater resources for irrigation,which was the main reason of groundwater table obviously dropping down.