Iowans have enjoyed nights with the windows open and the air conditioner off compared to the traditional sweltering heat and high humidity that are often the norm in July.
I.S.U. program specialist Richard Pope says while it’s good weather for sleeping, the cooler nights aren’t the best thing for developing corn and soybean plants. Pope says the cool nights make it a little difficult for the soybeans to set on pods and we’ve had some delayed development of soybeans. He says there have been some warmer nights lately that have helped the development.
Pope says the key now is what happens in August, as warmer temps and some more rain would keep the crop developing. He says beans are the biggest concern when it comes to nighttime temperatures.
Pope says the development model starts at 50 degrees and for soybeans they like to see the mercury drop no lower than 56. He says temperatures below 56 won’t kill the plants, but will “stop development quite a bit.” Since May 1st, Iowa is 143 to 205 degree days behind normal. Pope says weeds are another problem in these conditions.
Pope says some weeds can deal better with the cold, and with the beans developing slower, the leaf canopy isn’t as developed, allowing sunlight to get to the weeds. And the cooler wetter conditions in the spring made it tougher to get in and control weeds. “So this is also gonna be a year we are gonna remember as a year of weeds,” Pope says.
Pope says the slowed development is something farmers need to stay on top of — but he says it’s too early to write anything off. Pope says one year ago there was a lot of concern about a late crop, but then we had a nearly perfect August and we wound up with fairly normal crops in most places.
He says that can happen this year as we’re looking at a good crop right now. “If we can just get the right kind of weather in August, not to hot and not too cold, it’s just right. You know, like ‘Goldilocks and the Three Bears’. We’re looking for a ‘Goldilocks and the Three Bears’ August I guess,” Pope says.
Pope says but even 80-degree highs and 60-degree lows will help in August. The latest state crop report said 54% of the corn was rated in good condition and 26% excellent. While 59% of the soybean crop was rated good and 20% rated excellent.