With lower hay production in a dry year like 2018, beef and dairy producers may be relying a little heavier on silage production and may even seek out some grain corn producers willing to sell their corn for silage.
Ongoing drought conditions are making silage decisions difficult. Maturity appears to be very uneven, and also seems to have progressed extremely quickly in some areas. An important thing to consider is that even if a plant appears to be drying down, almost completely, it will likely still be maintaining a lot of its moisture in the stalk at this stage. Due to poor environmental conditions during pollination, there may be an increased incidence of plants with very small ears, or possibly none at all, which will also have an impact on plant moisture content. To determine if any given corn crop is ready for silaging, it will require several plants being tested in different areas of the field. Do not just go begin harvest based on the appearance of the crop because it looks more mature than it actually is, with regards to plant moisture.
There are two major factors when considering when to cut corn for silage: plant moisture and nitrate concentration. When a plant’s moisture is too high, there may be leakage and lead to spoiling when ensiling. When too dry, the silage may not ferment properly and lack the quality and energy the livestock require.
Nitrates accumulate in lower corn stalks when certain stresses (drought) reduce yield to lower than applied fertility levels. Nitrates can be toxic when fed to livestock and nitrate-rich silage may produce gases that are lethal to both humans and livestock. When a drought-relieving rain occurs, it may improve nitrate levels, however it is best to wait a few days to silage following the precipitation to allow time for the nitrates to lower back down. Data shows that nitrates generally accumulate in the bottom 6 - 8” of corn stalks, so to avoid silage with high nitrate concentrations, raise the cutter bar to 10 - 12”.
Source : Manitoba Corn Growers Association