Ammoniakförluster vid flytgödselhantering
myllning och surgörning som metoder för att minska avgång vid spridning
The ammonia emissions are an environmental issue since they contribute to eutrophication. By far the largest source of ammonia emissions is manure from agriculture and should therefore be reduced. Loss of ammonia is not only negative for the environment but also to the farmer who loses nitrogen that could have been used by the crop. The focus of this study has been emissions from spreading slurry where the loss can vary widely depending on slurry-, soil-, and weather conditions. There are mainly two different ways to reduce the emissions. One is to inject or mix the slurry into the ground to avoid air contact. The other way is to use acid to reduce the pH in the slurry to a level between 5 and 6 where the equilibrium is so strongly pushed to NH4+ that hardly any NH3 can be lost. Injecting slurry can effectively reduce the emissions under proper ground conditions but can also cause reduced yields because the roots are being damaged by the injection tines or discs. Another problem with this technique is the higher demand of draught force required and the lower capacity compared to band spreading. To reduce the pH of the slurry has been shown to be at least as effective as injecting slurry but without the troubles with root damages and low capacity since band spreading technique can be used. The negative side with acidification is the risk of handling strong acids, the cost of the acid and the fact that the technique is not established in Sweden and not proven during Swedish conditions. Low ammonia emissions can be achieved even without acidification or injection if the spreading is done under perfect weather conditions. If there isn?t perfect weather conditions during and after spreading slurry may acidification and injection be good ways to effectively reduce ammonia emissions.