by Katie Navarra
Wet, cool temperatures and the unpredictability created by the coronavirus pandemic are challenging farms on planting timely silage crops. The full impact of the weather on the 2020 growing season is still unknown; however, there are opportunities to implement strategies to improve the chances of a successful outcome regardless of what the season brings.
Joe Lawrence, forage management specialist for Cornell CALS PRO-DAIRY, led a webinar outlining the results of corn silage hybrid evaluation programs that can be useful in selecting hybrids. The program evaluates over 70 hybrids from over a dozen companies each year at multiple locations across New York and Vermont. The resulting information provides a useful decision-making tool.
“With corn silage or forage we talk a lot about what we can impact and what can’t,” he said. “Some of the research we’ve been doing with fiber digestibility is tied to the impact of weather conditions.”
Over the last few years there has been a focus on having the right forage quality for different groups of animals. The weather and COVID-19, which may pose labor concerns, can make “timeliness” feel like an unachievable ideal. That means hybrid selection as a management tool is even more critical.
Choosing maturities to match changing weather conditions
As much as farmers would like to control the weather, it is impossible. However, it is possible to implement management strategies for success despite the weather.
“Last year it started off wet and by the middle of the summer we saw some pineapple corn. Having the extremes of both in the same year is challenging,” he said.
Lawrence saw data presented at a conference last autumn that show the northeast is receiving about five more inches of precipitation each year as compared to 50 years ago. Most notably, the data indicated the rain is not distributed evenly throughout the year – 75% of it is arriving in autumn.
“When we think about corn silage harvest we’ve had a couple challenging harvest seasons recently related to weather conditions,” he said. “I don’t think it’s too much of a stretch to say that we need to be prepared for more of that.”
Picking maturities to fit the growing season
Choosing corn varieties based on what has traditionally performed well may not be enough to guarantee inventory that will last until the next harvest. Lawrence argues that choosing hybrids with a shorter season than what has been comfortable in the northeast may be necessary. That includes rethinking cover crop and double crop rotations.
“It’s a whole change in mindset because we don’t really need to or we shouldn’t just think about it in terms of adding a cover crop into our current rotation. Oftentimes that just leads to frustration and marginal benefits,” he said. “We need to think about changing our whole rotation so that all the crops we want to grow fit into it.”
One of the most obvious places to do that is shortening corn hybrid relative maturities to gain flexibility with planting and harvest windows. Regardless of where corn seed is bought, it is helpful to purchase based on past growing season’s performance data rather than picking arbitrary values to judge quality.
“I think it’s really helpful to use this sort of data to calibrate yourself to the growing season and say, well, here is what it averaged in previous growing seasons,” he said.
In many cases, drier soils are more important than the temperature at planting. There is still a risk when using hybrid seeds with treatment if the soil is cool; however, getting the corn in early enough to peak by harvest season impacts total volume.
The importance of timing
Lawrence pointed to data from Wisconsin showing two peaks of silage corn quality. The first peak is when maximum fiber digestibility is reached prior to tasseling. The next peak gives extra yield and better starch levels come from the extra yield.
“If we harvest an immature crop, we’re giving up a lot of yield. In Wisconsin, when planted by late May, 95% of their maximum yield was achieved,” he said. “After late May and into early June yield drops off rapidly.”
Timing doesn’t only affect yield – it also impacts quality. In the Wisconsin study, when planted past mid-May the rate of forage quality decline is more notable, especially in the central and northern zones.
“There might be more of a quality penalty on that side than a yield penalty in mid through late May,” he said. “Once we put that corn in the ground, we would like to see 50º temperatures and dry soils.”
Timing has equal consequences on the harvest end. When forced to harvest during mud season it is necessary to raise the cutter bar. Lawrence pointed to studies from Penn State that show a one-ton reduction in yield for going up six inches.
“If we take an 18 ton per acre yield, one ton is about 5.5%. If we look at what half a ton per acre represents, that represents about 2% to 3% of a yield,” he said. “Plus, we get into feed hygiene issues when we’re playing in the mud.”
The impact of frost is hard to quantify; choosing a longer season hybrid that is harvested after a frost can pose issues with fermentation or incomplete kernel maturity. That sacrifices more yield than what is gained.
In a perfect world, spring temperatures and moderate rainfall would arrive on schedule and last through harvest season. Since seasons are changing, planting strategies must also change. Make decisions based on data provides the best outcome.
Lawrence’s full webinar provides specific data and it can be viewed at https://tinyurl.com/ycjddste.