By Stefano Pinna, Poultney Mettowee Natural Resources Conservation District
This summer has been challenging for farmers across Vermont. A very wet spring led to a very late corn planting and a dry July/August stressed many hay fields in the Southwestern part of the State. Most corn fields are way behind compared to more “normal” years and the crops in many cases will be harvested wetter or later in the season. In this article we are providing a few tips to offset excessive moisture in the silage during harvest and some thoughts about cutting hay in dry years.
Corn Harvest:
Before harvest, it’s good practice to review how corn quality evolves over time in order to maximize the quality of our feed.
The chart below, from the University of Wisconsin, shows the amount of milk produced for each ton of corn, in relation to the growth stage of the crop.
As with any other plant, a peak in quality is reached right before flowering (V11 to V14) when the plant goes through a very rapid growth. Milk production per ton of feed is very high (black line) but milk production per acre (red line) is very low, due to little tonnage per acre.
Quality then starts to decline and reaches the lowest at R3 which is the milk stage, when a lot of the nutrients are moved from the roots and the leaves to the ear. After this stage, grains start to fill up very quickly and we get an increase in yield of approximately four bushels/acre per day over the next 30 days.
The peak in corn quality and milk per acre is reached at maturity. In an ideal situation we want to harvest at this stage, but this year things are a bit different and for those fields where the corn is still short it could make sense to move up the harvest to V11 rather than waiting for extra tonnage and increase the risk of getting a frost. If our corn has already passed milk stage but it’s not dry enough for ensiling and we cannot wait any longer (for example, if we have a custom operator scheduled in advance), I would suggest raising the cutting bar and leaving more material in the field.
In this way, you will increase the dry matter content of your silage by having proportionately more grains (which are the driest part of the plant) in it. This is particularly important when it’s time to pack that material in the bunker.
Having very wet silage in bunkers produces a lot of leachate that gets lost and potentially causes runoff issues. Also, a lot of leachate means losses in milk production, because leachate carries high levels of digestible sugars from the silage.
Another adjustment that can be used to avoid feed quality losses in leachate is to adjust the length of cut on the chopper. Tom Kilcer, from Cornell University, suggests using a cut length of one inch or more for highly digestible forages such as immature corn. The reason is that chopping corn at shorter lengths would potentially turn the forage into the consistency of soup, which would create issues when it’s time to pack that material in the bunker.
The last recommendation is to use a high quality homolactic bacteria to preserve the nutrients in the silage. Make sure to choose an inoculant that is designed for wet, high sugar forage. Kilcer from Cornell reports a gain of 2.3 lbs of milk/cow/day when an inoculant was used in the silage.
Hay fields update
A very dry July/August had some repercussions for the second cut of hay. Slow growth and cracks in the soil were the most evident signs of stress in the fields. The weather station in Rutland reported 2.12 inches of rain from July 15th to August 20th of which only 0.6 inches fell in early-mid August. Considering that most of that precipitation was received during very quick thunderstorms, plants and soils didn’t have enough time to adsorb it.
Here are a few tips to mitigate dry soils and crops during dry weather spells.
Leaving more grass in the fields can feel counterproductive, but it’s the easiest method to prevent the negative effects of a dry season. Every time we cut the grass low to the ground, leaving only 2 inches behind, we expose more bare ground to the sun which literally bakes it and, with clay soils, can turn it into something that resembles concrete. Also, the shorter we cut the plant, the more we force it to move nutrients stored in the roots for leaf regrowth. However, in a dry
year, the plant will struggle to move nutrients, and this will result in stunted growth.
In addition, the baking effect caused by the sun creates a crusted layer on the surface that prevents eventual rainwater from infiltrating into the soil.
Cutting the hay field to a higher height, allows longer leaves to remain in our fields and maintains shade on the soils, avoiding the formation of a hard crust on the surface. Second, leaving more stubble on the field helps the hay to dry up faster because air can flow underneath it.
The minimum recommended cutting heights are:
- 3 inches for Alfalfa
- 4 inches for grasses
Finally, leaving more vegetation in the field reduces the time in between cuts since the grass grows back faster and doesn’t have as much shock after cutting. Less nutrients, in fact, are required for leaves to regrow.
The Poultney Mettowee NRCD offers several services:
- Assistance understanding the programs and funding sources available to you
- Confidential on-farm assessments of regulatory compliance
- Assistance identifying potential water quality issues on the farm
- Renting of conservation tillage equipment (no-till drill, aerator)
- Portable tractor scales for weighting loads
- Comprehensive support for nutrient management plan establishment and updates.
Feel free to contact either of the agricultural program staff below for more information:
Stefano Pinna, (802) 373-5766 or stefano@pmnrcd.org
Jennifer Alexander, (802) 558-6470 or jennifer@pmnrcd.org