Recommendations for future work for including salt supplementation as a nitrogen mitigation in Overseer: Preliminary outline and proposed testing regime

Administering salt (sodium chloride) to grazing animals is a potential mitigation to decrease nitrogen (N) leaching and nitrous oxide emissions (an important greenhouse gas) from grazed pasture systems (Ledgard et al., 2015). Salt has a known diuretic effect, resulting in an increase in daily drinking water intake by grazing ruminants with an associated increase in daily urination volume (Ledgard et al., 2015). This leads to a decrease in the deposition rate of N in animal urine patches and increased recovery of urine-N by pasture, with subsequent reduced N loss potential (Ledgard et al., 2015).

Salt supplementation is defined as the deliberate administration of significant quantities of salt to the diet to change urination patterns. It excludes the use of salt for animal health or dietary requirements. The aim of this report is to summarise the results of salt supplementation research, how salt supplementation could be incorporated into Overseer, and to recommend an evaluation process of the implemented model.

Report no. RE450/2023/073