PA-Precision Agriculture Reduction of Ammonia Emission by Slurry Application Techniques

Livestock manures and slurries are, currently, almost entirely surface applied to land in the UK but research has shown that, under experimental conditions, injection of slurry or restricted surface placement, can considerably reduce ammonia (NH3) emissions following land spreading. In experiments reported in this paper, treatments were based around a slurry plot applicator, incorporating surface broadcast, band-spread, trailing shoe and shallow injection (open slot) application techniques. In a total of 16 experiments over the period July 1995-June 1997, NH3losses following application were significantly reduced (probability P<0·05) on five occasions by at least one of the modified application techniques and averaged, 40, 25, 23 and 17% of the ammonium-N (NH4-N) applied, respectively, for splash-plate, band spread, trailing shoe and shallow injection techniques. The overall reduction in NH3emissions provided by the bandspread, trailing shoe and shallow injection techniques, was 39, 43 and 57% relative to conventional surface broadcast application. Whilst application technique consistently affected NH3emissions, there was generally little observable effect on crop yield or nitrogen offtake in assessments undertaken within this project. It is apparent that soil moisture content, soil temperature, slurry dry matter content and crop growth are all factors with potential to affect the results obtained. Greater understanding of the interaction of application technique with these factors is required.