| Irrigation water use efficiency is an important basis for evaluating irrigation water use in irrigation area.Correctly evaluate the irrigation water use efficiency in irrigation area can provide a scientific theoretical basis for the development of irrigation water saving in irrigation area.Heilongjiang Province is an important commodity grain base in China,over the years,its irrigation water use efficiency were lower than that of the national average.At present,There are 338 large and medium irrigation areas,9136 small irrigation areas and 300,000 pure well irrigation area.The differences of irrigation water use efficiency between different types of irrigation areas are due to the differences of environmental and management methods,therefore,it is necessary to analyze the temporal and spatial variation of irrigation water use efficiency in different types of irrigation areas in Heilongjiang Province,find out the main influencing factors of irrigation water use efficiency,and scientifically make water-saving schemes,so that different types of irrigation areas can achieve a balanced growth of irrigation water use efficiency in Heilongjiang Province.Based on the survey of Heilongjiang Province irrigation area samples and experiment of some typical irrigation area samples,the temporal fractal characteristics and spatial distribution pattern of irrigation water use efficiency of different types of irrigated areas were analyzed.The influence factors of irrigation water use efficiency were analyzed by spatial modeling technique.Finally,from the aspects of engineering water saving and crop water saving,calculate the irrigation water saving potential.The water saving potential of large irrigation areas in Heilongjiang province were evaluated by the method set.The main research contents and results of this study are as follows:(1)Irrigation water efficiency index system and measurementThe irrigation water use efficiency,canal water use efficiency and field water use efficiency were determined as the index system of irrigation water efficiency in this study.The modified irrigation water use efficiency is calculated for the well canal combined irrigation area.The modified irrigation water use efficiency of the well canal combined irrigation area is calculated by the method with the consideration of groundwater movement and return water.The results showed that modified irrigation water use efficiency was higher than the traditional irrigation water efficiency.(2)Fractal characteristics of irrigation water use efficiency in Heilongjiang ProvinceIn order to study the fractal characteristics of irrigation water use efficiency in different typesof irrigation areas,the annual fractal characteristics of irrigation water use efficiency in different types of irrigated areas in Heilongjiang Province were studied by using the Rink-Scale method.The results showed that the annual fractal dimension D of irrigation water use efficiency in Heilongjiang Province in 2009 ~ 2014 was in the range of(5.26,6.25),and the structural characteristics of irrigation water use efficiency changed from multi-fractal to single fractal.The balanced maximum of irrigation water use efficiency in different types of irrigated areas is: when D1 = 4.58,?1 = 44.44% was for large and medium scale irrigation areas;when D2 = 4.79,?2 =53.81% was for small scale irrigation areas;when D3 = 6.98,?3 = 70.41% was for pure well irrigation areas,when D = 5.13,? = 57.03% was for the whole irrigation areas.(3)Spatial pattern of irrigation water efficiency index system in Heilongjiang ProvinceThe spatial distribution characteristics of irrigation water efficiency index system and its influence factors in Heilongjiang Province were studied by using geostatistics theory.The results showed that the field water use efficiency was the most affected by the spatial structure,and the spatial positive correlation range was 145 km.The irrigation water use efficiency was affected by the spatial structure,and the spatial correlation was 124 km.Water use efficiency is influenced by random factors,and the spatial correlation was the smallest.At the junction of Daqing,Harbin and Suihua,the irrigation water use efficiency,canal water use efficiency and field water use efficiency were all high,and the three indexes of Jixi were low.(4)Influencing factors of irrigation water use efficiency in Heilongjiang ProvinceThe irrigation water use efficiency was taken as the dependent variable,and eight main influence factors were selected: rainfall,evapotranspiration,water saving irrigation area ratio,canal lining ratio,irrigation project intact rate,canal structure complexity,irrigation project supporting rate;The ordinary least squares model(OLS)and geographic weighted regression model(GWR)were established respectively,the influence degree of each influence factor on irrigation water use efficiency in Heilongjiang Province was analyzed from the global and local perspectives.The results showed: In the global analysis,canal structure complexity and irrigation water use efficiency were negatively correlated with the irrigation water use efficiency,the other influence factors were positively correlated with the irrigation water use efficiency.The spatial distribution of the regression coefficients of the influencing factors was obvious in the local analysis.The spatial degree of the GWR model was higher than that of the OLS model because of the spatial factors.(5)Calculation of water saving potential in irrigtion areaIn order to estimate the water saving potential of irrigated areas,taking the Hulanhe irrigation area as an example,the irrigation water use efficiency and water production efficiency of Hulanhe irrigation area were calculated from the two aspects of "engineering water saving" and "crop water saving" by research and remote sensing technology.The results showed that the calculation of SEBAL model were in good agreement with the measured results.The irrigation water use efficiency are positively correlated with the rainfall,and negatively correlated with the net watervolume..The water saving potential of(1.702,5.103)×108 m3,(1.783,5.184)×108 m3,(1.865,5.266)×108 m3 and(2.301,5.702)×108 m3 were calculated for 5 years,8 years,11 years and 15 years respectively.Based on the cumulative frequency of water production efficiency in Hailanhe from 2007 ~ 2014,the water production efficiency target of the short-term water saving plan(near50% of the cumulative water production efficiency)and the long-term water saving plan(70%cumulative frequency of water production efficiency)were 1.03 kg/m3 and 1.22 kg/m3,respectively,and calculated the short and long-term cumulative water savings were 1.18×10 8m3 and 2.74×108 m3.(6)Irrigation water saving potential evaluationIntegrating 5 aspects of water volume,irrigation water efficiency,irrigation planting,irrigation benefit,irrigation environment,established the irrigation area water-saving potential evaluation index system of Heilongjiang province.Evaluated 23 large scale irrigation area samples using evaluation method set.The results showed that the the evaluation method set could revise circularly the results of single method results,which made the evaluation results more convincing,The correlation between the rank of water saving potential and the irrigation water efficiency index system were calculated,which showed that the correlation between canal water use efficiency and water saving potential of large irrigation area was largest. |
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