| It is an important basis for the optimal allocation of agricultural irrigation water resources and the improvement of agricultural irrigation efficiency by analyzing the analysis of the effective precipitation and crop water requirement in different fertility stages.Hebei Province is a large agricultural province,but also agricultural use of water in one of the larger areas in China.With the characteristics of uneven distribution of precipitation,and agricultural irrigation water is much higher than other industries and etc.Under the situation of relative deficit of water resources,the source of agricultural irrigation water almost comes from groundwater.According to statistics,the amount of groundwater in Hebei Province up to 5billion m~3,over-extraction rate of up to 23%.Long-term over-exploitation of groundwater for agricultural irrigation,not only in the region of water resources and water environment caused serious damage,but also caused the ground sinking,cracks and the risk of collapse,causing a great threat to human safety.Therefore,it is of great practical significance to clarify the effective precipitation and crop water requirement in Hebei Province,and to make rational use of water resources and improve the utilization rate of agricultural water resources.Based on the daily meteorological data,soil data and rainfall data of 13 meteorological stations in Hebei Province in recent 60 years.Select the three main crops were planted in Hebei Province,According to the current period of the agricultural sector for different years of different crop growth phase of the specific time statistics,based on the single-valued average coefficient method,the daily crop coefficients of the three main crops were calculated for the past 60 years.Then through the United Nations Food Organization recommended a series of crop water requirement calculation method,the water requirement,water deficit and moisture loss index of different crops in different sites in Hebei Province were calculated separately.Finally,analysis the time and spatial law of the effective precipitation and water requirement law of the three crops were analyzed by Man-Kendall(M-K)method,Morlet wavelet analysis method and ordinary Kriging interpolation method.The results showed that:(1)The winter wheat planting area is mainly distributed in south of the Great Wall which in addition to Chengde and Zhangjiakou outside the region in Hebei Province,mainly include13 meteorological stations.The whole growth period contain the initial growth period,freezing and thawing stage,wintering stage,fast development stage,middle growth period and maturation stage.The crop coefficient changes in the range of[0.40,1.29].In the past 60 years,the annual effective precipitation,water requirement and water deficit of winter wheat in Hebei Province showed no significant decrease,and there are about 40 years of the main cycle.The average annual effective precipitation is 51.47mm,the average crop water requirement was600.72mm and the average crop water deficit was 594.26mm.The moisture loss index showed no significant decrease trend,the average value was-0.91.The maximum effective precipitation and moisture loss index in the whole growth period appeared in Handan,the values were64.27mm and-0.88.The maximum water requirement and water deficit were appeared in Nangong,the values were 711.32mm and 661.59mm.The spatial distribution of effective precipitation and water requirement law in different growth period is different.(2)The summer maize planting area is mainly distributed in the south of Langfang area in Hebei Province,mainly include 8 meteorological stations.The whole growth period contain the initial growth period,fast development stage,middle growth period and maturation stage.The crop coefficient changes in the range of[0.49,1.24].In the past 60 years,the annual effective precipitation,water requirement and water deficit of summer maize in Hebei Province showed significant decrease,and there are about 40 years of the main cycle.The average annual effective precipitation is 90.39mm,the average crop water requirement was 345.96mm and the average crop water deficit was 255.56mm.The moisture loss index showed no significant decrease trend,the average value was-0.74.The maximum effective precipitation in the whole growth period appeared in Handan(105.52mm),the maximum water requirement appeared in Huanghua(375.02mm),the maximum water deficit appeared in Huanghua(282.26mm),the maximum value of moisture loss index appeared in Handan(-0.66).The spatial distribution of effective precipitation and water requirement law in different growth period is different.(3)The cotton planting area is mainly distributed in addition to Chengde,Zhangjiakou and Qihuangdao outside the region in Hebei Province,mainly include 11 meteorological stations.The whole growth period contain the initial growth period,fast development stage,middle growth stage and maturation stage.The crop coefficient changes in the range of[0.30,1.29].In the past 60 years,the annual effective precipitation,water requirement and water deficit of cotton in Hebei Province showed significant decrease,and there are about 40 years of the main cycle.The average annual effective precipitation is 117.82mm,the average crop water requirement was 575.71 mm and the average crop water deficit was 457.89mm.The moisture loss index showed no significant decrease trend,the average value was-0.79.The maximum effective precipitation in the whole growth stage appeared in Handan.The maximum water requirement and water deficit were appeared in Huanghua,the values were 618.10mm and496.57mm.The maximum value of moisture loss index appeared in Handan(-0.79).The spatial distribution of effective precipitation and water requirement law in different growth stages is different. |
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