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Farm cooperation: swapping clover grass for manure & slurry

Clover grass in the crop rotation ensures soil stability and increased soil fertility – benefits that stockless farms like to take advantage of as well. Cooperations also have the advantage that manure and slurry can be used to fertilise other fields as required.

A farm cooperation with an arable farm exchanging clover grass for manure and slurry from livestock farms was tested in Upper Austria.

With an exchange ratio of 1 t of clover grass silage for 1.2 t of manure (conventional), 95 % of the N exported with the clover grass returned to the farm, as well as 77 % of the carbon and 69 % of the potassium. For phosphorus, calcium and magnesium, one-and-a-half to double the amount was returned.

In the slurry cooperation, with an exchange ratio of 1 t of clover grass silage for 2.35 m³ of slurry (organic), significantly less of the carbon exported with the clover grass came back, namely only 29 %. Of the nitrogen, 79 % returned, 70 % of the phosphorus, 46 % of the potassium, and all Ca and Mg. Remarkably, copper, zinc, manganese and iron came back in much higher quantities from the conventionally managed farm with the manure, presumably through the supplementary feed of the cattle.

The manure cooperation performed significantly better than the slurry cooperation in terms of CO2 emissions and costs: 254 kg CO2e vs. 614 kg CO2e for 1000 kg C applied to the recipient field; with costs for 100 kg N of 400 € vs. 895 €.