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More data needed on cover crops and nitrogen leaching

A water quality specialist in Wisconsin says more data is needed to help determine how much cover crops help control nitrate leaching in soils.

Guolong Liang with the University of Wisconsin Extension tells Brownfield cover crops reduce nitrate leaching into groundwater but, “There are several researchers actively doing research projects on this topic however we don’t have enough data yet.”

Liang says for example, in sandy soils, the heavy rains can easily wash nitrates downward, even when using cover crops. “All of the biomass you’ve accumulated from the previous season is very likely to mineralize during that process, which means that it will transport from organic nitrogen into ammonium and nitrate, and that doesn’t prevent us from nitrate leaching.”

Liang says more collaboration is needed between farmers and researchers to gather data about nitrate losses with cover crops on different soil types.