石家庄平原区粮食施肥增产对地下水开采量演变影响研究

通过对近30年来石家庄平原区农业开采地下水量与化肥施用量和粮食产量之间的关系研究,揭示了化肥施用在小麦玉米产量耗用地下水开采量中的影响作用。结果表明,化肥施用量增加使小麦玉米产量的增幅大大超过农用地下水开采量增幅,从而使单位小麦玉米产量所耗用的地下水开采量不断减小,从20世纪70年代的1.86 m3·kg-1减小到2000—2005年间的0.72 m3·kg-1。如果没有化肥的增产效用,按照20世纪70年代的化肥施用量水平(0.17 t·hm-2),达到现状的粮食生产规模需要耗用的地下水开采量将大大增加,20世纪80年代、90年代、2000—2005年间平均分别需要多耗用地下水10.35×108 m3、18.88×108 m3和20.12×108 m3。但是21世纪初期单位面积上化肥施用量水平已较高,继续增加化肥施用对粮食单产及单位小麦玉米产量耗用地下水强度影响不大。

Impact of fertilization and high grain production on groundwater exploitation in Shijiazhuang Plain

Shijiazhuang Plain is one of the main grain production areas in Hebei Province,cultivating mainly winter wheat and summer maize.Increased grain production in the plain is closely related with groundwater exploitation.This is because there is almost no surface runoff in the plain and winter wheat and summer maize cannot do well without irrigation.Generally,production increases with increasing groundwater exploitation.However,the rate of increase in grain production is bigger than that of groundwater recent years due to fertilization.Hence groundwater consumption intensity for wheat and maize yield is dropping.It is therefore critical to study the impact of fertilizer use on groundwater consumption in the agricultural sector.This paper analyzed the variations in groundwater exploitation for wheat and maize production.It also analyzed the effect of increased grain production on groundwater exploitation.Furthermore,the paper discussed the relationship between fertilizer use and per-unit wheat and maize yield.The results showed that increasing fertilizer use had led to decreasing groundwater exploitation for wheat and maize yield.While groundwater use was 1.86 m3·kg-1 in the 1970s,it dropped to 0.72 m3·kg-1 at the start of the 21st century.According to 0.17 t·hm-2 fertilizer use in the 1970s without considering yield-increasing effect of fertilization,groundwater exploitation sharp increased to get the total production levels of today.For example,groundwater exploitation respectively increased by 10.35×108 m3,18.88×108 m3 and 20.12×108 m3 in the 1980s,1990s and 2000—2005.From the relationship between fertilizer use and per-unit wheat and maize yield,fertilizer use reached 0.76 t·hm-2 to have the max per-unit wheat and maize yield.In the early 21st century,however,fertilizer use per-unit area was 0.72 t·hm-2,which was close to the 0.76 t·hm-2 dose for max yield.Hence with increasing fertilizer use,there was little potential to increase production and decrease groundwater use.