There has been a lot of discussion about the impact of the El Niño weather cycle on North American weather conditions. El Niño is the warming phase, but soon we may be faced with La Niña, or the cooling phase. But even if we do get a La Niña later this year it doesn’t necessarily mean that the Northeast will be cooler than normal. In fact, some models predict that while the Pacific Northwest and parts of the Deep South will be cooler, beginning in mid- to late-summer, much of the northeastern U.S. will be warmer than normal. These same forecasts suggest that precipitation amounts in this part of the U.S. will be less affected than will temperature.
What steps should farmers take when anticipating these possible events? My recommendation is that farmers shouldn’t make drastic changes in their crop management – including seed selection – based on predictions of what could happen. We’re all well aware of the problems and pitfalls of forecasting the weather more than a couple of days in advance. Meteorologists have improved their near-term forecasting ability – we tend to remember their errors more than their successes – but weather forecasting is still far from reliable.
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Don’t get caught short
Consider the impact of changing your seed corn order to hybrids with relative maturity (RM) 10 days or so longer than what you normally plant. What can you gain? You may gain a few percentage points higher yield, with no appreciable difference in silage or grain quality. State university trials show slight increases in yield for hybrids with 10 days longer RM where the growing season is sufficient for them to properly mature but no difference in quality. But what will you lose if frost arrives before the corn has reached its proper state of maturity? For grain harvest this can mean that the crop will remain standing in the field waiting for the grain to dry. It can also result in lower test weight and higher drying costs after harvest. Reduced grain quality is likely because if there’s still a lot of moisture in the grain, then ear molds can set in prior to harvest. For silage harvest the impact can be even worse: Repeated trials by universities and seed companies have found considerably lower whole plant digestibility when corn is chopped for silage before the recommended stage of maturity, normally 32 percent to 35 percent dry matter, but this can differ slightly with hybrid and growing season. Corn chopped for silage at less than 30 percent DM will almost always have less milk production potential and an increased chance of silage effluent. As corn matures from the dough stage to the proper harvest maturity, the plant is adding grain weight every day. The wet weight of the crop doesn’t change much during these couple of weeks, but dry weight and grain weight increase daily. Therefore, you have more to lose by getting caught short with a long-season corn than you have to gain – from yield and quality standpoints.
Short- or long-term weather and climate changes
Weather is the state of the atmosphere at a given time and place. This includes variables such as temperature, precipitation, wind velocity and barometric pressure. Climate is the meteorological condition including temperature, precipitation and wind. Therefore, since both El Niño and La Niña are temporary in nature, usually lasting less than one growing season, they represent changes in weather, not climate. Growing season temperatures in the northeastern U.S. and eastern Canada are increasing and have been doing so for some years now. This is proven in the field by the increasing ability of farmers to plant corn hybrids and soybean varieties that take longer to mature. For instance, 30 years ago in northern New York we were able to plant soybean varieties that were in the “0” maturity group with a good chance they’d mature prior to a killing frost. We could mature only the earliest Group 1 varieties, though in some areas even that was a risk. Cornell University research has found that we can now plant later-maturing soybean varieties with higher yield potential. Similarly, we’re now successfully maturing corn hybrids that are five to 10 days longer in relative maturity than we were planting a generation ago. This has much less to do with El Niño, La Niña or other short-term weather changes than with a long-term change in climate.
However, let’s not lose sight of the impact of improved longer-season crop management. Over the years we’ve learned that soybeans are more tolerant of cool, early season weather than they once were, and the combination of improved cold tolerance and better seed treatments allows farmers to plant corn and soybeans a week or so earlier than their fathers and grandfathers did. “The book” states that corn needs a soil temperature of 50 F and soybeans 54 F to germinate and grow. However, on many farms improved soil drainage and tillage have resulted in the soil warming faster in the spring. During spring a wet soil is a cold soil, so improving drainage can mean getting into field a bit sooner: Not only will the field tolerate equipment better, but the soil will more quickly warm to the desired temperature. Therefore, though our climate is changing, so is farmers’ ability to lengthen the growing season via improved crop and soil management.