New Zealand’s dairy farm systems produce large quantities of nutrient rich effluent which are captured from milking sheds, holding yards, feed pads, standoff pads and animal shelters. These products are often highly variable combinations of faeces, urine, teat washings, wash down water and bedding materials. This effluent is commonly grouped into three broad categories based on dry matter (DM) content: liquids (0–5%), slurries (5–15%) and solids (>15%).
Management of these effluents is typically via land application to pasture. Less common is the use of effluents as a nutrient source to grow high value forage and arable crops (e.g. maize, fodder beet, brassicas, cereals) which are commonly integrated onto the milking platform or support blocks.
In a cropping context, using effluent either to supplement or replace fertiliser presents an opportunity to capitalise on a cost-effective nutrient resource while improving whole farm nutrient use efficiency.
The Forages for Reduced Nitrate Leaching research programme has produced a publication called Using dairy effluent to grow crops – an update for industry, farmers and consultants. The guide summarises key aspects relating to the use of effluents to grow crops, including effluent nutrient composition, nutrient supply, chemical characterisation and application considerations.
Forages for Reduced Nitrate Leaching is a DairyNZ-led collaborative research programme across the primary sector delivering science for better farming and environmental outcomes. The aim is to reduce nitrate leaching through research into diverse pasture species and crops for dairy, arable and sheep and beef farms. The main funder is the Ministry of Business, Innovation and Employment, with co-funding from research partners DairyNZ, AgResearch, Plant & Food Research, Lincoln University, Foundation for Arable Research and Manaaki Whenua-Landcare Research.