Factor analysis of environmental impact of manure utilization

Modern livestock farms feature a large number of animals and subsequent significant environmental load. The biggest negative impact is on the atmosphere and on water bodies, with manure being the major pollution source. The proper choice of an effective low-cost manure handling technology with low nutrient loss ensures the environmentally sound operation of these farms. Manure utilization is understood as a set of activities, including manure processing, manure storage (if necessary) and soil application of produced organic fertilizers. It is important to deal The article considers the nitrogen loss during manure utilization depending on such factors as type of manure processing, manure storage conditions, soil application practices, moisture content of raw manure, nitrogen-carbon ratio in the raw manure, and quality of the staff. To identify the dependence of nitrogen loss from these factors a method of logical-linguistic modelling was applied, by which the expert data were formalized in a mathematical model. In view of the differences of processes, which take place during the storage and processing of liquid and solid manure, two models were considered - for liquid manure with the moisture content is greater than 92 % and solid manu re with the moisture content is less than or equal 92 %. The analysis of the coefficients of the obtained equations showed the significance of each factor and their mutual dependence. Most significant factors were the type of manure processing and the soil application method. The simulation study results were compared with the values obtained by measurements on operating farms, with the maximum inaccuracy being 5.35 %. The obtained equations may be used for express calculation of nitrogen loss and to forecast the variations of nitrogen loss under different manure handling technologies.