| With the rapid development of industrialization,urbanization and agricultural modernization,agricultural soil and water resources have become two rigid constraints restricting grain production in China.In the face of a series of practical problems,such as the imbalance of water resources development and the rapid increase of paddy field area,too high exploitation intensity of groundwater and underutilization of surface water have seriously affected the dynamic balance of water resources and the improvement of agricultural production capacity.Sanjiang Plain is the most important area of japonica rice production in China.As the basic unit of developing paddy production,irrigation areas have important research value in exploring the improvement of grain production capacity.Therefore,the analysis of the impact of irrigation areas on cultivated land use and productivity can provide scientific basis for coordinating the distribution of water resources and the distribution of agricultural productivity.It is of great scientific research significance and practical meaning to guarantee the food security of the country and to promote the sustainable development of the agricultural health.Based on the boundary vector data of irrigation areas,this paper analyzes the quantity,scale and spatial distribution of irrigation areas.In order to explore the influence of irrigation areas on cultivated land use,this paper compares and analyzes the differences of cultivated land scale,cultivated land use structure,cultivated land location index and landscape index between irrigated and non-irrigated areas by using vector data of arable land in 2015.In order to explore the influence of irrigation areas on cultivated land productivity,this paper superposes NPP spatial data and cultivated land utilization data in 2000,2005,2010 and 2015,and analyzes the inter-annual variation characteristics and spatial distribution differences of cultivated land NPP between irrigated and non-irrigated areas.The main contents and conclusions of this paper are as follows:(1)Analysis of distribution characteristics of irrigation areas in Sanjiang plain.There are obvious regional differences in quantity,scale and spatial distribution of irrigation areas.The quantity of irrigation areas is as follows:Songhua River basin > Wusuli River basin > Heilongjiang River basin,and the number of irrigation areas in agricultural area is larger than that in reclamation area.The scale of irrigation areas is as follows:Wusuli River basin > Songhua River basin > Heilongjiang River basin,and the proportion of irrigation areas in reclamation area is obviously higher than that in agricultural area.In addition,the distribution of the quantity and scale of irrigation areas in different basins shows that the lower reaches of the river are larger than the upstream regions.The distribution patterns of irrigation areas in each basin are mainly uniformdistribution,and individual basins show agglomeration and random distribution.The distribution of irrigation areas in reclamation area is more uniform,and the distribution of irrigation areas in agricultural area is more random.The distribution advantages of irrigation areas in different basins show a trend of increasing gradually from south to north and from west to east.The distribution advantages of irrigation areas in lower reaches of river are higher than those in upstream areas.Moreover,the distribution advantages of irrigation areas in reclamation area are much higher than those in agricultural area.It shows that the centralized management mode,flat terrain and sufficient water resources in the reclamation area make it more advantageous than the agricultural area in the construction of irrigation areas.(2)Analysis on the influence of irrigation areas on cultivated land use.The reclamation rate of irrigated areas is significantly higher than that of non-irrigated areas(85.54% and 46.03%respectively),and the reclamation rate in reclamation area is higher than that in agricultural area.In different cultivated land use structure,the irrigated areas are dominated by paddy field,which accounts for 78.45% of the cultivated land area in the irrigation areas.Meanwhile,the non-irrigated areas are dominated by dry land,which accounts for 68.20% of the cultivated land area in the non-irrigated areas.The area of irrigated and non-irrigated paddy field in reclamation area is larger than that in agricultural area,while the dryland area in both irrigated and non-irrigated areas is smaller than those in agricultural area.There are obvious differences in location index and landscape pattern between irrigated areas and non-irrigated areas.The location index of paddy field and cultivated land in irrigated areas is higher than that in non-irrigated areas,while that in dry land is lower.In different regions,the location index of paddy field and cultivated land in irrigated and non-irrigated areas in reclamation area is higher than that in agricultural area,while that in dry land is lower.In irrigated paddy field and non-irrigated dryland,patch aggregation is lower,landscape fragmentation is smaller,man-made disturbance is lower,and patch area is quite different,while non-irrigated paddy field and irrigated dryland show the opposite.In different regions,the landscape fragmentation degree of paddy field in both irrigated and non-irrigated areas in reclamation area is lower than that in agricultural area,while that in dry land is higher.The man-made disturbance degree of paddy field and dryland in irrigated and non-irrigated in reclamation area is higher than that in agricultural area.Furthermore,the difference of patch area between irrigated and non-irrigated paddy field in reclamation area is larger than that in agricultural area.The difference in patch area among dryland in reclamation area is larger than those in agricultural area,while that in non-irrigated areas is smaller.It shows that the conditions of cultivated land resources development in irrigation areas are better,and the accumulation degree of paddy field and cultivated land resources is higher,which is more conducive to large-scale production and professional management,and the performance is more obvious in reclamation areas.(3)Analysis on the influence of irrigation areas on cultivated land productivity.In terms of time,the average NPP of irrigated and non-irrigated cultivated land showed an increasing trendduring 2000-2015,in which,the average value of NPP of irrigated paddy field decreased first and then increased,while the average value of NPP in non-irrigated paddy field showed an increasing trend.In the meantime,the average value of NPP in irrigated paddy field was higher than that of the non-irrigated areas in the four-period.The average value of dry land NPP in irrigated and non-irrigated areas increased,except in 2010,the average NPP of dryland in irrigated areas was higher than that in non-irrigated areas.Moreover,the coefficient of NPP variation of cultivated land,paddy field and dry land in irrigated areas was lower than that in non-irrigated areas.From the spatial point of view,the average NPP of cultivated land in Sanjiang Plain was generally higher in the north-central part,lower in the northeast and the south.The change trend of NPP in cultivated land,paddy field and dry land was mainly slight increase type from 2000 to 2015.The area with slight and significant increase of NPP in non-irrigated cultivated land and dry land was larger than that in irrigated areas.The area of NPP increased slightly and significantly in irrigated paddy field was larger than that in non-irrigated areas.For the productivity level of different grades of cultivated land,paddy field and dry land.The middle-yield cultivated land was the type with the highest proportion of cultivated land productivity in each grade of irrigated areas,while non-irrigated areas showed fluctuation.The middle-yield paddy field was the type with the highest proportion of paddy field productivity in irrigated and non-irrigated areas,and the increasing area of middle-yield paddy field and high-yield paddy field was higher than that of non-irrigated area.The productivity level of dry land in irrigated and non-irrigated areas showed fluctuating changes,meanwhile,the area increase of high-yield dry land in non-irrigated areas was obviously higher than that in irrigated areas.This indicates that the productivity of cultivated land,paddy field and dry land in irrigated and non-irrigated areas were generally increased.The quality of cultivated land in irrigation areas was more homogeneous.The agricultural production stability,disaster resistance ability of cultivated land in irrigation areas were better than those in non-irrigated areas.Moreover,the increasing trend of paddy field NPP in irrigation areas was more obvious,and the irrigation areas were more advantageous in increasing the yield of paddy field,while the non-irrigated areas were more suitable for the development of dry land crop cultivation. |
