In the US west (west of the 100th Meridian, or roughly the 20″ rainfall line), we worry more about drought than anything when we consider crop success or losses. Moisture, then too much heat, then frost seems to be the usual priority list.
Not this year. It is too cool to plant cotton, and maize is . . . interesting, based on the hybrids commonly grown in this area. The winter wheat looks OK, or did as of Sunday afternoon’s windshield survey.
When we talk about energy use in a building, we refer to “heating degree days,” based on a temperature of 65 F. In theory, at that temperature, a building uses the minimum amount of energy to be heated or cooled. However, I have heard it used in agriculture, as a short-hand for growing degree days. Growing degree days refers to the amount of heat energy needed for plants and insects to germinate, grow, and mature. They are very, very important in thinking about yield development and what type of seed to plant, if you are in an area that has a comparatively short growing season.
Different plant species have different GDD optima, but most food crops (corn, many wheats, soybeans, sorghum) do better above 50-55F, and growth levels off above 85F or so. Cotton needs a minimum of 60F, while alfalfa can take 41F. Soil temperature is also important, because if the soil is below a certain temperature, the seeds won’t germinate. They stay dormant, then rot if there’s enough moisture. There’s a “sweet spot” for ideal planting conditions, and then again for ideal growing conditions. Too hot and things can bake if the weather is dry, plus bugs get a head-start. Too cool and growth is slow and yields don’t reach their best level. Different pest plants also do better under different conditions. (Some places in the US and elsewhere have fields underwater. Unless you grow rice, that’s not a great situation, and even then you need the water to recede from time to time.)
Right now, the Texas Panhandle has been cool and dry. Too cool for cotton to be planted, and for most of the maize (corn) hybrids that are common in the area. If a farmer usually plants 120-day corn (estimated days to maturity and harvest), switching to 90-day corn can’t be done quickly. First you have to find someone with the seed, then get it down here, and so on. We’re pushing the northern edge of cotton growth up here, because we are cooler than where cotton usually grows (Deep South, South Plains). With cool soil and chilly weather, the farmers can’t get seed into the ground. This pushes back maturity and harvest, and no one wants unripe cotton to get hit by a freeze or snow (like October of 2019.) Ditto food crops.
Traditionally, US farmers worried about drought and heat, while Europe worried about cold and wet. This spring? Lots of the US and Europe are cold and wet. Solar energy output is low, which doesn’t help things like tomatoes. Anecdata about hone-grown tomatoes suggests that people are having to use cold-climate tomato breeds farther and farther south, and have been for the last decade or so. Canada has lost a lot of its grain to cold and wet weather the past few years. Global warming? Perhaps, but certainly not this spring, based on the weather patterns, and it is year-to-year that we produce food and fiber.
The High Plains region had a hard freeze the past two nights, with high temperatures in the 40s-50s. Things are supposed to warm over the next few days, then cool again. The Midwestern grain belt? Cool and damp. I haven’t been watching grain futures to see what the market thinks, but I would not be at all surprised to see futures prices start going up if the planting prognosis continues to be less than great.
I like cool weather for being out and about in. It’s not so great for agriculture.