Evaluation of mitigation strategies to reduce ammonia losses from slurry fertilisation on arable lands

To evaluate the best practices in reducing ammonia (NH3) losses from fertilised arable lands, six field trials were carried out in three different locations in northern Italy. NH3 emissions from cattle slurry were estimated considering the spreading techniques and the field incorporation procedures. The measurements were performed using long term exposure samplers associated to the determination of the atmospheric turbulence and the use of the backward Lagrangian stochastic (bLS) model WindTrax. The results obtained indicate that the NH3 emission process was exhausted in the first 24-48h after slurry spreading. The slurry incorporation technique was able to reduce the NH3 losses with respect to the surface spreading, where a contextual incorporation led to reductions up to 87%. However, the best abatement strategy for NH3 losses from slurry applications has proved to be the direct injection into the soil, with a reduction of about 95% with respect to the surface spreading. The results obtained highlight the strong dependence of the volatilisation phenomenon by soil and weather conditions.