Ammonia emissions from broiler manure during handling

摘要

Broiler manure from poultry farms has become a commercial fertiliser mainly for farmers with ecological production. However, there is a lack of knowledge about nutrient losses from broiler manure during storage and after spreading within crop production. The aim was to determine what happens to the material during the course of handling, with special emphasis on ammonia losses, and to see how different measures affect the amount of ammonia losses. Broiler manure was stored for seven months from October until May. The manure was placed in two separate heaps, one uncovered and one covered with a 30 cm thick layer of straw. Ambient air temperature and temperatures in the heaps were recorded continuously. Ammonia emissions were measured five times during the storage period. A micrometeorological mass balance method, described by Schjomng et al. (1992) and applied by Karlsson (1994) was used. At the end of May, broiler manure from the uncovered heap and a commercial product based on broiler manure (Binadan) were spread on arable land at a rate of 110 kg total-N per ha. Ammonia emissions were measured from plots fertilised with broiler manure and Binadan, respectively, with and without harrowing four hours after spreading. A micrometeorological methodof measuring gaseous NH_3 was used, which is based on passive diffusion sampling close to the ground (Svensson, 1994). Temperature measurements in the heaps during storage revealed high biological activity. The highest temperatures were observed in thecovered heap. Despite this, the nitrogen lost in the form of ammonia was limited. The cumulative ammonia losses in per cent of total N were 7 percent from the uncovered heap and 10 percent from the covered heap. In total, 13.5 percent of the total nitrogen in the broiler manure was lost as ammonia after spreading without incorporation of the manure and 7.5 percent was lost from plots with incorporation four hours after spreading. After incorporation no ammonia emission occurred. No emissions occurred from plots fertilised with Binadan.