Nitrogen fertilizer replacement value of dairy soiled water in grass swards as affected by timing and rate of application

Abstract

Dairy soiled water (DSW) is produced on dairy farms from the washing of milking plant and cow holding areas during the milking process.In Ireland, and in other countries such as New Zealand, Australia and the UK, dairy soiled water (or, dairy shed effluent, or dirty water) is commonly collected separately to slurry from animal winter housing. In Ireland, this is a policy requirement for it to be considered as dairy soiled water (SI 605 of, 2017). Dairy soiled water typically consists of a relatively dilute mixture of cow faeces, urine, spilt milk and detergents, and therefore contains plant nutrients. The dry-matter (DM) content of DSW in Ireland would be typically <1% (Minogue et al., 2015), compared to typical cattle slurry/liquid manure DM contents of approximately 2%-16% (e.g.