By Gregory W. Roth
We could see some rain this week on drought stressed forages and this could set up for nitrate accumulation silo gas and wetter forage next week. This article shares a few ideas for managing that situation.
In some areas, the drought has been eased a bit and the corn is recovering somewhat. In other areas, salvage harvests have started and now some rain is in the forecast. Under these conditions an accumulation of nitrates could be an issue in corn fields that have been heavily manured and chopped immediately after a drought ending rain. To reduce nitrates in drought stunted crops, its best wait at least 3 days after an appreciable rain after crops have had some exposure to warm sunny days. Ensiling corn usually reduces nitrates by 50 to 60%, so wait at least 3 to 4 weeks before feeding to allow a good fermentation to complete. Then test any suspect silage before feeding it to animals and consult with your nutritionist on a feeding program. Nitrates in fermented silage are fairly rare, based on a Cornell study, but its best to err on the safe side.
Another important consideration is the formation of silo gas during the first few days of fermentation under these conditions. High nitrate forage could contribute to nitrogen dioxide production. Each year we hear of incidents of silo gas exposure to producers and livestock. Be aware of the danger and avoid entering silo before thoroughly ventilating. Review our Silo Safety factsheet if you anticipate harvesting drought stressed forages this summer and make sure all employees are aware of the risk.
The final consideration is rehydration of the silage. Often when significant precipitation occurs, we can experience an increase in moisture levels in corn, especially in immature crops that had dried down due to drought stress. Be sure to monitor dry matter levels when harvesting resumes to avoid harvesting silage that is too wet.