(April 20, 2018) - Cover crops can benefit production agriculture, particularly by providing nutrients accumulated or fixed during winter and early spring to the cash crop. However, understanding rates of nutrient release from different cover crop species will be critical to time termination to optimize nutrient availability and reduce potential losses.
In the January-February issue of Soil Science Society of America Journal, researchers in southern Illinois report on the timing of nitrogen release from above and belowground biomass of two popular cover crops: hairy vetch and cereal rye.
The group found that hairy vetch shoots and roots decomposed much faster than cereal rye, likely due to higher initial N content. In fact, hairy vetch released 70 kg ha-1 N within just 4 weeks, whereas cereal rye only released 5 kg ha-1. This burst of nitrogen by hairy vetch could be lost if termination occurs too early or planting happens too late.
These results suggest that if growers choose hairy vetch, they should delay termination until as close to planting as possible to decrease the risk of N loss prior to crop uptake. Future work could explore cover crop mixes to optimize nutrient cycling and synchronize N release with crop uptake.