WHOLE FARM NITROGEN BALANCE ON POULTRY FARMS IN CENTRAL BOSNIA REGION

UDK 636.2:66.074.32(497.6) At livestock farms most part of nitrogen arrives as purchased products (fertilizer, animal feed and purchased animals). Within the boundaries of the farm, nitrogen recycles between the livestock and crop components. Finally, nitrogen exit a livestock operation unit preferably as managed outputs (meat, crops and manure) sold off the farm. Difference between the inputs and the managed outputs represents an itrogen balance that can be an indicator of environmentally sustainable production. Nitrogen (im)balance consider only amount of the nutrient that cross the border of the farm. In ideal conditions the nitrogen input/output ratio should be 1:1. Some nitrogen exits the farm as losses to the environment (nitrates in groundwater, ammonia volatilized into the atmosphere, and nitrogen into groundwater and surface water). A study was conducted on five small poultry farm in order to determine whole farm nitrogen balance as difference between total nitrogen inputs (one day chickens, litter, animal feed) and outputs (meat, dead animals and manure). Selected farms differ according to capacity (ranging from 5,000 to 40,000 birds), producers of poultry feed, type and length of manure storage as well as other sensible farming practice which could influence on nitrogen balance. Collection of data on all farms is done using a questionnaire. Nitrogen content in all substrates (feed, manure, litter) was determinate by Kjeldahl procedure. The results of the whole farm nitrogen balance with the recommendations of its balancing in order to reduce the negative environmental implications are presented in the paper.