The microbial product Kopros may help reduce methane and ammonia emissions from dairy cattle housing. Researcher Herman de Boer has found initial indications of this potential. The treatment altered several properties of the manure.
Dairy farmers sometimes use additives in their cattle housing to reduce emissions from slurry. Emissions of substances such as ammonia occur when urine and faeces mix on the floor of the housing. At the same time, dairy farmers want to increase the fertilising value of the manure when it is applied to agricultural land.
De Boer investigated whether the product Kopros B could fulfil both functions by testing whether the treatment changes certain properties of the manure. Kopros needs to be sprayed onto the housing floor periodically. The micro-organisms are expected to multiply in the manure on the floor and subsequently continue to act in the slurry pit.
Estimated ammonia reduction of almost a third
Measurements of various manure properties indicated that applying Kopros could reduce both methane and nitrogen emissions. Based on these findings, the researchers estimated that ammonia emissions from the cattle housing decreased by 30% or more during the study period. This percentage was derived from changes in manure composition and does not represent a directly measured reduction in emissions.
One possible explanation for lower ammonia emissions is that the micro-organisms used form a protective biofilm on the housing floor or on the surface of the slurry in the pit. A biofilm is a thin, slimy layer of micro-organisms that attach themselves to a surface. Whether such a biofilm actually forms and has this effect remains to be investigated.
Effects after manure application
The higher pH and ammonium content following treatment with Kopros mean that the manure could produce higher emissions after being applied to agricultural land. However, the treated slurry is also less viscous, allowing it to infiltrate the soil more quickly and counteracting the effects of the higher pH and ammonium content. Further research is needed to determine the overall effect on ammonia emissions after manure application.
The research was conducted by Wageningen Livestock Research and funded by the municipalities of Altena and Woudenberg, Rabobank, the Mesdagfonds and Novus AgroEcology.
Read the full report: Effecten van Kopros op ammoniakemissie en stikstofwerking van rundveedrijfmest.
