Study On Soybean Evapotransiration,Drought And Irrigation System In Heilongjiang Province

Soybean production occupies an important position in Heilongjiang Province.With the increase of soybean export and the expansion of planting area,it is great of significance to clarify the law of Evapotransiration,the characteristics of drought and the division of irrigation system in the growth period of soybean in Heilongjiang Province.In this paper,the author collected the meteorological data of 28 stations and 22 agricultural meteorological stations in Heilongjiang Province.According to the soybean crop coefficient selected by FAO,the growth period;The effective precipitation,evapotransiration and irrigation evapotransiration in the growth period of soybean were calculated,the three index changes were analyzed by M-K trend test and mutation test,the path analysis of evapotransiration and meteorological factors in the growth period of soybean was conducted,the spatial distribution of the three indexes was analyzed by Arc Map spatial analysis function,and the relationship between water supply and demand in the growth period of soybean was further explored;According to the drought frequency of soybean growth stage,Heilongjiang Province is divided into different regions,and the representative stations are selected to divide the water year of each representative station,and the change rules of effective precipitation,evapotransiration and irrigation evapotransiration of each station are analyzed.The irrigation systems of different water years are formulated by using CROPWAT model,which provides suitable irrigation systems for different regions.The results of this study are as follows:?1?The average annual effective precipitation in soybean growth period is 321 mm,which increases first and then decreases from west to East.The average climate tendency rate is positive,showing an upward trend in L_ini;The climate tendency rate of L_deve is on the rise in the western region;the average annual effective precipitation of L_mid is 143 mm,and the effective precipitation of 14 stations is on the decline;the average annual effective precipitation of L_late is 72 mm,and the climate tendency rate is on the decline in the western region,and on the rise in the eastern region.The spatial distribution of effective precipitation in L_deve,L_mid and L_late showed a trend are same.?2?The average annual evapotransiration of soybean is 388 mm,the west is decreasing from south to north,while the East is increasing from south to north,the average climate tendency rate is negative,and the overall trend is decreasing;The evapotransiration of L_ini is decreasing from west to East,and the average value of climate tendency rate is decreasing;The average annual evapotransiration of L_deve soybean in the west is decreasing from south to north,while that in the East is increasing from southwest to northeast,and the overall climate tendency rate is decreasing;The climate tendency rate of lmid is generally on the decline in L_mid;the average annual evapotransiration of L_late is 76 mm.Through general analysis,it can be seen that the inhibition effect of sunshine hours on soybean evapotransiration is the largest,the contribution of net radiation hours through sunshine hours on soybean evapotransiration is the largest,the contribution of humidity hours through sunshine hours on soybean evapotransiration is the largest,the inhibition effect of radiation on Soybean Evapotransiration is the largest,the contribution of wind speed and over radiation on soybean evapotransiration is the largest,and the contribution of sunlight hours through sunshine hours is the largest The inhibition of soybean evapotransiration was the most.?3?The average annual irrigation evapotransiration of soybean is 79.6 mm.From west to East,it decreases first and then increases.The climate tendency rate is an overall decreasing trend.From north to south,it decreases in the eastern region;In L_ini period,the distribution trend from west to East decreases first and then increases,the average value of climate and meteorological rate is negative,and the overall trend is decreasing;The average value of L_deve period is 29.5 mm,which shows a trend of decreasing first and increasing later from west to East;The average value of L_mid is 44.3 mm;From west to East,the distribution trend of L_late period decreased first and then increased which is the same L_deveand L_mid?4?The average annual CWSDI of soybean is-15%.From west to East,it increases first and then decreases.The average value of climate tendency is 1.64%/dec,which shows an overall upward trend;In L_ini stage,the CWSDI increased gradually from west to East,and the climate tendency rate was positive;In the period of L_deve,L_mid,and L_late,CWSDI first increased and then decreased from west to East.In the period of L_deve,the climate tendency rate was positive in the southwest,and negative in the East.The average value of lmid was 1.4%/dec,which showed an overall increase trend.The CWSDI in the period of L_late showed a downward trend.?5?In L_ini period,the frequency of light drought increased first and then decreased from east to west,the frequency of moderate drought decreased from north to south,the frequency of heavy drought decreased and then increased from west to East,the frequency of severe drought was the highest in West,the second in East,and the smallest in middle;The frequency of light drought is higher in the northwest of L_deve,and the frequency of moderate drought is decreasing from west to East,then increasing.The frequency of severe drought is decreasing first and then increasing from west to East in the East and Nenjiang,and other places in the West;The frequency of light drought in L_mid decreases first and then increases from west to East,the high value of medium drought frequency distributes more in the northwest and East,the frequency of heavy drought decreases first and then increases from west to East,and the frequency of serious drought decreases from west to East;In the period of L_late,the spatial variation trend of light drought frequency was not obvious,the high value of medium drought frequency was mainly distributed in the central and eastern areas,the frequency of heavy drought increased from west to East,and the frequency of severe drought decreased from northwest to south.In L_ini stage,the frequency of middle drought and above decreased from west to East,while in the other three periods,it decreased first and then increased;the distribution trend of drought intensity was similar to that of middle drought and above.?6?In general,the effective precipitation in soybean growth period is Sui fenhe>Jiamusi>Qiqihar,and the evapotransiration and irrigation evapotransiration are opposite;the evapotransiration of different water years in L_mid period of each station is larger than that in other periods;the net irrigation quota of Suifenhe,Jiamusi and Qiqihar in wet,normal,dry and extremely dry years is 0.34,97.7,132 mm,0,88.1,124.1 and 156.9 mm;91,130.6,152.9 and171.9 mm.