Optimization Of Crop Planting System Under The Condition Of Reducing The Exploitation Of Groundwater In The North Of China

The buried depth of groundwater level in North China Plain is unstable under the influence of temperature and rainfall changes and human irrigation activities.In this article,based on field data and related analysis,a conclusion was drawn as follows by analyzing amplitude of underground water table,amount of precipitation and change of underground water table under climate change's effection of recent 15 years.(1)In the period between 2001 and 2015,average temperature and average amount of precipitation was increased by a small amount of 0.019?/a and 6.16mm/a respectively.(2)The mean yearly production volume was decreasing year by year along with the increase of the amount of rainfall and production of grains,however the underground water table was still lowering.Superficial water level was lowered by 0.7m/a,deep level water height was lowered by 4.25 m/a.(3)The setting depth of underground water was constantly increasing,a certain regularity was found,the maxium setting depth was 42.46m which is recorded in Aug 2014.(4)Deep level water height was more likely to be affected by evapotranspiration volume and amount of precipitation.In order to solve the problem what excessive exploitation of groundwater,in this paper,the groundwater depth data provided by hydrology and Water Resources Surveying bureau in Hebei province,"Hebei Water Resources Bulletin" Query the data of irrigation water,China meteorological Science data Sharing Service Web site to find rainfall data to carry out field experiments,existing cropping system and irrigation methods under the premise of Analysis on planting structure of Hengshui crops:(1)Reducing the amount of irrigation water and adopting water-saving irrigation methods,the total output is almost flat under the extent that the amount of irrigation by drip irrigation is only 40%of that by flood irrigation.In the case that the amount of irrigation water by the micro-sprinkler irrigation method is only 60%of that by the flood irrigation method,the total output is increased by about 23%.(2)Strengthen water resources management,change crop irrigation system.Winter wheat under adequate conditions,reduce joint water irrigation,summer-corn can grow without irrigation,reduced consumption of total irrigation water,and keep the total output relatively stable.(3)Change planting methods and increase land use efficiency.Based on the traditional winter wheat-summer corn rotation model,increased the cultivation of crops such as oil sunflowers and high-consumption grasses such as oil grass and spring grasses between winter wheat and spring maize.(4)Rration ally optimize planting structure,improve economic efficiency.When the average price of water is 0.60 yuan/m3,when the planting area of winter wheat is relatively reduced,when the planting area of winter wheat is relatively reduced,the amount of irrigation water consumed will be reduced accordingly.Can appropriately reduce the planting area of winter wheat,increase the cultivation of cash crops such as fruits and vegetables and cotton.