Microorganisms show promise for reducing emissions from manure

This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Dairy farmers sometimes use additives in their cattle housing to reduce emissions from slurry. Emissions of substances such as ammonia occur when urine and feces mix on the floor of the housing.

At the same time, dairy farmers want to increase the fertilizing value of the manure when it is applied to agricultural land. De Boer investigated whether the product Kopros B could fulfill both functions by testing whether the treatment changes certain properties of the manure. Kopros needs to be sprayed onto the housing floor periodically.

The microorganisms are expected to multiply in the manure on the floor and subsequently continue to act in the slurry pit. Measurements of various manure properties indicated that applying Kopros could reduce both methane and nitrogen emissions. Based on these findings, the report showed 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 microorganisms 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 microorganisms that attach themselves to a surface.

Whether such a biofilm actually forms and has this effect remains to be investigated. 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. For the study, a dairy cattle house with a slatted floor was divided into a treated and an untreated section. Each section had its own slurry pit.