Effect of frequent manure mixing on emissions

What are we investigating?

The manure storage contributes 25% to the total methane emissions in the dairy farm. Dairy stables in the Netherlands are traditionally equipped with slatted floors above a deep manure cellar. The manure often remains in the basement for a long time and after spreading, a layer of old slurry often remains in the basement. This layer forms the basis for methane formation, even when new manure enters the basement. In these conditions, a rotting process takes place that releases greenhouse gases and ammonia.

Frequent manure mixing may affect the formation of these gases. There are indications that briefly aerating the manure can reduce the emissions of methane and ammonia, among other things, in a more effective way than with the manure mixer. It is not yet known whether other mixing techniques, such as mixing by pumping manure around (usually in the Netherlands), give comparable results. This project will investigate these techniques.

Why is this important?

Through this research we can:

• gain insight into the effect of aeration and pumping of manure on emissions;
• determine how much each source (animals and manure storage) contributes to the total emissions from the dairy farm;
• find out what effect the removal of the 'leftover' manure from the manure cellar has on the methane emission.

The aim of the research is to gain insight into which solutions for methane reduction for livestock farmers can be efficient, feasible and profitable. Agriculture has been commissioned to indicatively reduce 3.5 megatonnes of CO2 equivalents by 2030, of which 1 megatonnes from methane. This research contributes to achieving this objective.

Which activities do we carry out?

Throughout 2019, we are investigating various ways of mixing manure at the Dairy Campus in Leeuwarden. We investigate two techniques: aerating and pumping manure around. In three rounds of about three months, we measure the effect of these two mixing methods on emissions and energy consumption.The emissions of methane, nitrous oxide, carbon dioxide and ammonia are continuously recorded.

When do we expect results?

We expect the first research results in the spring of 2020. We are expected to deliver the official reports in mid-2020. The results of this research are relevant for a large group of livestock farmers and can be used in both new and existing stables.

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This research was funded by the Ministry of Agriculture, Nature and Food Quality in the context of climate policy