Cultivated Land Change Induced Water And Land Balance Effect In Naoli River Bain

As the bottleneck factors of land use for regional agricultural,the quantity of water resource owns the significant effects whether the land use structure was reasonable.The unreasonable utilization of water resources resulted in a set of unsustainable land resource problems that places a serious constraint on the future of food security,economic development and social stability in dry areas.Naoli River Basin,as the watershed which was cultivated earliest in Sanjiang Plain that located in the Northeastern of Heilongjiang Province,it was one of the most important reclamation area since the establishment of since the founding of new China.Since early 1990s,the agricultural structure of Naoli River Basin has been greatly adjusted with large amount of dry land which could be easily waterlogged changed into paddy field,water shortages have steadily worsened during the past decade,led the agricultural irrigation water increased sharply,which brought the continued decline of groundwater table,and a series of ecological environment problems caused by secondary.The key point was how to coordinate the distribution of agricultural production,the ecological environment protection in the rational use of local distribution conditions of water resources,which has become serious problems that need to be solved urgently.It should then start to design everything it does around the use of water resources and land resources,intensity of the resources and the coupling relationship between them,which would contribute to the effective protection for the local sustainable utilization of land resources and ecological environment.In recent years,the drastic expansion of the paddy field in the Naoli River Basin has resulted in a change in the underlying surface conditions and a great change in the mechanism of the yield and confluence,which has made obvious changes in the water cycle links such as vegetation interception,land evaporation and soil infiltration,and the change of the balance of soil and water resources.This article follows the research train of thought of "theoretical mechanism process simulation strategy response",focusing on the major practical needs of comprehensive response to the balance of water and soil resources under arable land utilization.Taking the Naoli River Basin as the research area,based on the grey theory,the theoretical hypothesis of cultivated land information statistics is proposed,and then the spatial distribution data of the effective cultivated land in the Naoli River Basin are extracted and the arable land pattern is studied.Based on the information of the balance factor of soil and water resources,the distributed hydrological model based on the remote sensing drive is constructed,and the research area is simulated on the day by day scale.The water and soil resources are divided into 3 levels,and the balance situation of soil and water resources at 3 levels of climate,crop and soil and the balance effect of soil and water resources under the cultivated land use are discussed by increasing the limiting factors by step by step.The water resources balance of the river basin is integrated with the balance of water and soil resources and precision irrigation management.The main conclusions are as follows:(1)The theoretical hypothesis of the cultivated land information statistics is put forward,that is,on the premise of excluding the special plots with large area(such as large woodlands and construction projects),in the area of a certain area of non cultivated land,the area of non arable patches with a certain area interval is calculated and several times accumulated,and the data will be displayed.Significant exponential regression characteristics.By mining the "grey" rule of the change law of non cultivated land information,we can predict the accuracy of grey prediction under different intervals.Then the spatial distribution information of the effective cultivated land in 2000,2005,2010 and 2015 was extracted.The results of the study on the pattern of effective cultivated land showed that the water field process was extremely strong in the Naoli River Basin during the 15 years,the coefficient of water field increased from 10.23%in 2000 to 23.39%in 2015,and the area of dryland was sustained.The main axis of the dry land distribution in the 4 studies is distributed along the north-east and south-west.It has a very strong randomness and discrete type in the space,and the area of water field in the dry land concentration area is also larger.The spatial distribution of paddy fields is clockwise,the distribution tends to be centralized,and the distribution center of gravity slowly moves southward;(2)The difference of rainfall characteristics in the Naoli river basin is more obvious than that in the Sanjiang plain,the rainfall in the basin in the summer is gradually decreasing,the rainfall in the Sanjiang reclamation area is slowly rising,and the water supply conditions of the Naoli River basin gradually become worse,and the characteristics of this change are also reflected on the potential evapotranspiration and the vegetation on the surface of the surface.On the elements,the supply situation of water resources is getting worse.(3)Balance of water and soil resources is essentially the problem of temporal and spatial matching of water resources and land resources.Due to the coupling relationship between water resources and land resources,the balance between water and soil resources should be incorporated into complex systems to carry out research.The remote sensing driven hydrological model(RS_DTVGM)constructed in this paper can be used to simulate the daily inversion of surface runoff,soil flow,potential evapotranspiration and actual evapotranspiration in the Naoli River Basin.At the same time,the data test results show that the model has good applicability in the river basin.At the same time,the runoff simulation results show that the runoff distribution in the Naoli River Basin is very different,the runoff in the southern and southeastern regions is low,and the surface runoff of the Naoli River main stream and the inside and outside Qixing River is high.(4)The study on the balance effect of soil and water resources shows that,for the climate water balance,the Naoli Basin is in a "negative" climate water profit and loss situation for a year,and the absolute value of the profit and loss in the western and northeastern Rao counties is significantly greater than that in the middle and South regions,and the overall trend is decreasing from west to south.At the same time,the high value area of summer profit and loss is just the low value area in winter.With the dramatic changes in the internal structure of cultivated land,the absolute value of climate water and loss in dry land and paddy field declined year by year,and the climate water profit and loss situation in the paddy field became more and more severe,and the total amount of profit and loss in 2015 reached-31.77 ×108 m3.The water deficit is the common feature of the climate water balance in the Naoli Basin,and the water problem in the paddy field will still be the focus of the comprehensive utilization of agricultural resources in the Naoli River Basin and the Sanjiang plain area.(5)In the water balance of crops,the water profit and loss characteristics of middle rice,spring wheat and spring corn vary greatly.Most of them are in the state of mild water deficit,and the profit and loss of spring wheat is the best.Most of the area is in the state of normal water profit and loss between 2000-2015 years.For spring corn,because of its water demand for spring corn.At the same time,spring maize in dry crops is the most important crop type.In 2000,the light water shortage area accounted for 94.43%of the total area,and the proportion of mild drought area in the other years was 17.65%,31.24%and 24.08%in the other years.(6)In terms of soil water balance,the water deficit situation in 2000 is more severe than that of 2005,2010 and 2015 for the 3 major crops.For middle rice,water shortage is the most important characteristic of soil water balance in this basin.At the same time,there is a significant difference between different years.Deficiency is also the characteristics of soil moisture balance in Spring Maize in the multi year cropland of the Naoli River Basin,but spring maize in some areas is in a state of water surplus.Spring maize showed obvious water balance characteristics of water deficit farmland,but its soil water balance situation gradually improved.At the same time,in terms of soil moisture balance of cultivated land,the balance situation in 2000 was extremely severe,with severe and severe water shortage,and 2005,2010 and 2015 were mild and moderate water shortage.(7)For the balance of water and soil resources in the basin,Fujin,friendship County and Jixian county are in the condition of irrigation and water shortage,in which the water shortage in Fujin is 2.71 ×1.1 m3,the corresponding water field balance is 556.76 km2,which is the most severe irrigation situation in the basin.The relative water shortage situation and the balance of the paddy field in Baoqing county are good.584.68 km2,for dry land,the irrigation guarantee degree in each county is basically the same as that in the paddy field.That is,Baoqing County,Rao River County,Qitaihe city and Shuangyashan city are in the development surplus state,and the existing water supply conditions in Fujin,friendship and Jixian counties can not meet the needs of their cultivated land.(8)In order to ensure the comprehensive utilization of soil and water resources in the Naoli River Basin,it can be carried out from 4 aspects:the scientific adjustment of crop structure,the implementation of precision irrigation management of farmland,the implementation of interregional water diversion project and the rational exploitation of groundwater,in which the precision irrigation management of farmland can be constructed by the principle of intelligent body model(Agent).(AgentLA)under the double layer target management area with complete irrigation layer and high irrigation demand.In view of the comprehensive exploitation and utilization of water resources and land resources in the Naoli River Basin,the local government should scientifically adjust the structure of cultivated land(Fujin,friendship County and Jixian county)on the basis of the assessment of soil and water resources balance,and implement the water diversion project between regions in order to ensure the distribution of water resources across the region and take the combination of the water resources.The management measures of precision irrigation can reduce the consumption of agricultural water under the condition of sufficient water supply of crops,and rationally exploit the groundwater resources according to the distribution of groundwater.This study is of great value to the development of agricultural structure adjustment,farmland precision irrigation management and construction of high standard farmland in the modern agricultural test area of the Naoli River Basin and the Sanjiang plain area.It enriches and perfects the study of soil and water resources balance,and has strong theoretical significance and practical value.