Transport Of Nitrogen And Phosphorus Nutrient Salts In Large-Scale Dairy Farming

With the rapid development of large-scale breeding industry,the application of dairy farming waste as organic fertilizer to farmland soil has become a hot trend in the treatment of farming waste.However,due to its characteristics of containing a lot of nitrogen and phosphorus nutrients,it may cause environmental pollution of farmland soil and surrounding groundwater.In this paper,through the monitoring of nitrogen and phosphorus nutrient content and ammonia volatilization in the farmland soil and soil water solution after different fertilization management,the movement law of nitrogen and phosphorus nutrient salt after the large-scale dairy cattle breeding waste returning to the field was studied,providing scientific basis and reasonable suggestions for the organic manure returning to the field.In the experiment,cow manure and effluent from tertiary oxidation pond after fermentation and composting were used as organic solid and liquid fertilizers.According to the local irrigation practice,field management included Q00management without fertilizer application,75%solid and 75%liquid fertilizer+top dressing 75%,50%,25%liquid fertilizer,namely SQ7575,SQ7550,SQ7525,SQ5075,SQ5050,SQ5025 management.Top dressing of base fertilizer was applied 100%,75%,50%,There are 11 kinds of field management of 25%liquid fertilizer,namely Q100100,Q7575,Q5050 and Q2525.The main conclusions are as follows:(1)There was a significant correlation between the average content of total phosphorus in each layer of soil under different field management;the average content of soluble phosphorus in the soil under solid fertilizer and liquid fertilizer field management was 2.37 times of that under liquid fertilizer field management,0-20cm soil was easy to produce Fe-P precipitation;the application of oxidation pond wastewater was beneficial to the formation of calcium and phosphorus,and inhibited the absorption of phosphorus by plants;the average content of moderately active organic phosphorus in the soil The content is the highest in four forms of organic phosphorus,two orders of magnitude higher than the average content of active organic phosphorus and medium stable organic phosphorus,and one order of magnitude higher than the average content of stable organic phosphorus;SQ7575 field management plants have the highest phosphorus content;the total phosphorus content of soil water samples at 20cm depth is lower than 40,60 and80cm;SQ5050 management is the most likely to produce the risk of soil phosphorus leaching.(2)With the increase of depth,the average content of total nitrogen in the soil of different depth and field management gradually decreased;the amount of nitrogen application had a significant positive correlation with the average content of nitrate nitrogen in the soil of different depth of field management;the content of total nitrogen and nitrate nitrogen in the soil solution was the highest at 40 cm and the lowest at 80 cm;nitrate nitrogen was the main form of nitrogen in the soil solution;The total nitrogen content of plants under SQ7575 management is the highest;the nitrogen conversion rate of SQ5025 field management is the highest,and the nitrogen conversion rate of Q100100field management is the lowest;leaching is the main project of farmland nitrogen output,and the nitrogen loss of SQ5075 field management is the largest;the average value of nitrogen surplus is 117.6 117.6 mg/m~2 in the balance of 11 kinds of field management nitrogen.(3)The volatilization rate of ammonia in 10 kinds of field management was close to the control group's Q00 management level from the first day after applying base fertilizer and top dressing,respectively.The amount of nitrogen application was significantly related to the total amount of soil ammonia volatilization in corn planting cycle.The loss of nitrogen produced by ammonia volatilization was 0.29%-1.08%.The accumulation of ammonia volatilization in different field management after applying base fertilizer and top dressing was studied by logistic nonlinear regression model.The result of dynamic fitting is better,R~2 is greater than 0.95.