An enhanced software tool to support better use of manure nutrients: MANNER- NPK

MANNER-NPK (MANure Nutrient Evaluation Routine) is a decision support tool for quantifying manure (and other organic material) crop available nutrient supply. The user-friendly design of an earlier version of MANNER was retained, but in response to user and stakeholder feedback, additional functionality was included to underpin new and revised nitrogen (N) transformation/loss modules (covering ammonia volatilization, nitrate leaching and nitrous oxide/di-nitrogen emissions, and organic N mineralization) and also to estimate manure phosphorus (as P2O5), potassium (as K2O), sulphur (as SO3) and magnesium (as MgO) supply. Notably, MANNER-NPK provides N availability estimates for following crops through the mineralization of organic N. Validation of the crop available N supply estimates was undertaken by comparing predicted values with data from more than 200 field experimental measurements. For cattle, pig and poultry manures, there was good agreement (P<0.001) between predicted and measured fertilizer N replacement values, indicating that MANNER-NPK provides robust estimates of manure crop available N supply and N losses to the wider environment.