Study On The Balance Effect Of Soil And Water Resources In The Black Soil Region Of The Northern Songnen Plain

The Black soil region of Northeast China is an important food production base in China.However,the area of wetland and woodland has been greatly reduced,the area of dry land and paddy field has been increasing,and the water demand in the region has been increasing because of people's irrational use of land resources.The situation of crop water deficit in the region is increasing continuously.The north of Songnen Plain is located in arid and semi-arid region.Water resources are the key factors restricting the development of regional agriculture and the unreasonable use of land resources.The serious mismatch between water resources and land resources in the region restricts the sustainable development of the economy and the safety of food production in the region.In addition,the black soil area in the northern part of the Songnen Plain is located in the transitional zone between the Lesser Khingan Mountains and the Songnen Plain.Due to the influence of leeward slope in the Lesser Khingan Mountains,this area has become one of the regions with the least rainfall in Heilongjiang Province,and the rainfall in Songnen Plain is mainly distributed in July to August,accounting for about 70%of the total rainfall in the whole year.Leading to frequent seasonal drought and waterlogging disasters in the region,known as"ten years and nine spring droughts".Therefore,to clear up the water profit and loss situation in the black soil region of the northern Songnen Plain during different growth periods is of great importance to ensuring the safety of grain production in the region.It is of great significance to protect the ecological environment in the region and the sustainable use of the land in the black soil area.Based on this,this study takes the black soil area in the north of Songnen Plain as the study area,and takes 1985 years,1995 and 2015 years as the time points,through collecting the meteorological data and hydrological data of the long time series in the study area.On the basis of Budyko's coupled equilibrium theory of water and heat,the parameters?equation is fitted again by using the data of land use data and soil attribute data.Finally,the fitting equation which accords with the parameter?of this research area is obtained,and the calculation of parameter?and the actual evapotranspiration is carried out,which is easier to reflect the actual evapotranspiration under different land use conditions,geomorphological characteristics and soil properties.Therefore,the evaluation of soil and water balance effect is carried out accurately,and the situation of water profit and loss under the condition of land use change and climate factor change is analyzed in order to make rational use of soil and water resources in the ecotone of agriculture and animal husbandry,and to coordinate the distribution of agricultural production.And for the realization of regional sustainable development to provide reference and reference.?1?In the recent 30 years,the land use of the black soil area in the north of Songnen Plain is mainly dry land,the area of wetland and woodland is decreasing year by year,the area of dry land,paddy field and construction land is increasing gradually.The area decreased by 1737.9 km²,the area of dry land increased by 1412.5 km²,the area of paddy field and woodland increased by 351.8km²,and the area of paddy field increased by 351.8 km².The forest land was reduced by 305.9 km²;for construction land,the change was not very obvious over the past 30 years,with an increase of94.4 km².?2?In recent 30 years,the average potential evapotranspiration in the north of Songnen Plain ranged from 432.8 mm to 605.8 mm,and the distribution of the potential evapotranspiration decreased gradually from southwest to northeast of the region.The change trend of the potential evapotranspiration in the study area is gradually increased from the middle to the north.The variation trend of the whole region is-0.51 mm a^-1,and the variation trend of each month in the growth cycle is-0.27 mm a^-1?-0.16 mm a^-1?-0.09 mm a^-1?-0.03 mm a^-1 and 0.02 mm a^-1;the temperature increases year by year at 0.3?/10 a,and the rainfall shows no obvious change trend.But rainfall fluctuates more and more.?3?According to the actual situation of the study area,the actual evapotranspiration obtained from the fitting parameter?can effectively reflect the land use status,geomorphological characteristics and soil properties.This can greatly improve the accuracy of calculating actual evapotranspiration.From the overall variation of actual evapotranspiration,the distribution of actual evapotranspiration in the north of Songnen Plain is gradually increasing from northwest to south,and the actual evapotranspiration in time decreases first and then increases,and generally shows an upward trend.?4?According to the balance effect of soil and water resources,the water deficit situation was greatly affected by climate change from 1985 to 2015.The water deficit rate increased gradually from 1980 to 2009,and the water deficit rate decreased from 2010 to 2015.At the same time,due to the increase of paddy field and dry land area,the area of wetland and woodland decreased greatly,which aggravated the situation of water deficit in the north of Songnen Plain.As a whole,the average water deficit rate between 1985 and 2015 was 0.25?0.2?0.31 and 0.13,respectively.It can be seen that the water deficit situation in the north of Songnen Plain is fluctuating up and down,and the value of water deficit in 2011-2015 is small,which may be caused by the abundant rainfall and other climatic conditions in the study area in recent years.?5?On a monthly scale,the most serious months of water deficit in the north of Songnen Plain are May and June,and the more serious ones are August and September.Because the area of paddy field and dry land is increasing continuously,especially for paddy field,the water demand of paddy field in May and June is obviously larger than that of wetland,and the water demand of forest land is higher than that of wetland,which exacerbates the water deficit degree in May and June.?6?From the point of view of the annual change trend,the water profit and loss situation in May?June and July is in the form of fluctuation and decreasing trend,but the fluctuation range of water deficit is increasing,due to the influence of climate factors.The results show that the intensity of water deficit does not decrease when water shortage occurs from May to July.For the water deficit in August and September,the water deficit fluctuated up and down,and the fluctuation range of water deficit decreased.It shows that the probability of water deficit in August and September becomes higher,and its performance is relatively stable.Because of the influence of land use change,the degree of water deficit increased in every month during the growing date,and the obvious change was in May and June.The purpose of this study is to analyze the water profit and loss of crops during the growth period under the change of land use and climate factors.So as to provide reference and reference for regional land use,promote the sustainable development of regional agricultural economy.