Experimental Study On Water And Fertilizer Distribution Of Irrigation Uniform And Non-uniform Application Conditions

Nowadays,used in agricultural irrigation nitrogen fertilizer is one of the most important pollution source of agricultural non-point source pollution in our country.Surface irrigation is the most widely applied irrigation mode on the yield in our country,its water and fertilizer use efficiency is generally low,excessive loss of fertilizer pose a threat to the environment.Therefore,express the conditions of surface irrigation,do the technology research on fertigation,it has significant theoretical significance and application value to enhance the nitrogen use efficiency on the yield and lighten the agricultural non-point source pollution.So far,on one hand,research results at home and abroad using bromide as a tracer to simulate the running condition of nitrogen in soil profile and change trend of temporal and spatial distribution.On the other hand,minority focused on very soluble nitrate fertilizer.The study shows,the traditional method is that do artificial surface broadcasting of nitrogen fertilizer firstly and surface irrigation secondly,irrigation water is easy to wash the solid fertilizers that are even broadcasted on the yield,that results in the uneven distribution of fertilizer on the yield.Solute concentration in surface-subsurface flow on the end of border has significant difference on previous each measuring point,he content of soil nitrogen increased significantly on the end of border under the broadcast mode and reduce the fertilizer use efficiency.Therefore,do experimental study on the distribution of soil moisture-nitrogen movement under the non-uniformity broadcast mode of border irrigation,it would have great significance for practical application on establishing the reasonable mode of border strip fertigation.Study on the object of winter wheat,through getting the datas of field trial after ammonium sulfate applied in the growth period,this thesis tries to do research on the change trend of temporal and spatial distribution under the uniformity and non-uniformity broadcast mode of border irrigation in returning green stage.Analyses on sulfate ion and ammonium ion distribution law of temporal and Spatial variability in surface flow,the spatial distribution of the soil water content and sulfate ion on 2 hours before the irrigation and pouring irrigation after 2 hours,And the spatial distribution of the soil water content ?nitrogen and sulfate ion and on 2 hours before the irrigation and pouring irrigation after 2 hours?5 hours?10 hours and 40 hours for typical border irrigation.The system evaluation is given for the uniformity and non-uniformity broadcast mode of border irrigation,and do discuss suitable operation mode of border strip fertigation.Through the study of the above content,the main conclusions and innovation of this article,as follows.By Analyzing the dynamic changes of the concentration of ammonium nitrogen and nitrate nitrogen in 0~80cm and 0~40cm soil layers during winter wheat growth periods,ammonium nitrification occurs mainly in pouring irrigation after 2 hours,a large amount of ammonium ion in irrigation water have translated into nitrate after infiltrating.Pouring irrigation after 10~40 hours,the concentration of ammonium nitrogen are decreased but its changing scale are small,the concentration of nitrate nitrogen are decreased in plant uptaking at the moment,the concentration of ammonium nitrogen and nitrate nitrogen showe a declined tendency on the whole.Now we can say that nitrification-denitrification is weak;Nitrification-denitrification happen in pouring irrigation after 5~10 hours and 40 hours~ before harvest,the phenomenon what the concentration of ammonium nitrogen are increased while the concentration of nitrate nitrogen are decreased has appeard during these two periods.Based on what non-uniform broadcast ammonium sulfate has uniformity of soil application and fertilizer efficiency,non-uniformity broadcast mode of border irrigation would balance that irrigation water could make the difference on in washing?carrying and moving for fertilizer.Enhance the uniformity of soil and fertilizer,it would form the conditions on the temporal and spatial distribution of water and nitrogen on the yield that would help to uptake and utilization the uniform distribution of water and fertilizer for crops,it is adequate for during winter wheat growth periods.