So as we find ourselves grinding through the month of August, we also have experienced a cool down. With these cooler temperatures has come an opportunity to look at our soybean strategy. Usually, August is when things pick up for our Soybean irrigation scheduling. We find ourselves at R4 to R5 right now depending on the maturity of the beans in our field. With that still comes a tremendous amount of water use, probably somewhere in the neighborhood of 5.5” or a little more. And while some people look at the number of weeks to maturity (6-7) and water use is about the same, they have an irrigation plan of 1” per week to meet their needs. But with this strategy comes several opportunities for failure as well.
With our AquaSystems platform, I think that most growers will tell you that it is every bit as important understanding when not to water as it is to water. With soybeans, this is especially true. As we look at the negative effects of overwatering, like excessive vegetative growth, lodging, and white mold, we have plenty of reasons not to over water. I was adamant back in the early part of July about not watering our soybeans unless they were truly at drought levels. I stand by that statement. I saw several fields in Northern Nebraska that had no rain from May 25th to July 25th that need 2-3 shots of water to stay alive and healthy. Anything more than that was for our benefit as producers to feel as if we were doing something to help this crop.
But now we have transitioned to the other side of the coin. With the demands that soybeans have in the last 1/3 of their life that I talked about before, can we still afford to be patient? My answer: absolutely. We have done our homework and studied these plants all season long. One of the benefits of being conservative with the amount of water to our beans early is that we developed roots. And by roots, I mean significant roots. Several fields of beans I look at have 30”-40” of active roots under them this season. As we enter mid-late August and go to September, we need to remember that those roots are there to help this crop along. Watering every time the top 8 inches is dry is more detrimental than beneficial. If White Mold hasn’t hit you in the last few years, I am willing to bet you know some neighbors that it has. Keeping the surface from being wet any more than possible is one of the best strategies against White Mold we have.
So that is the take home for today. Even though our water use will ramp back up with some warmer weather, patience still pays when it comes to irrigating soybeans. I have seen it enough times to know that we can work these soybeans backward to manage our water for the rest of the season. While we are still a good 2 to 3 weeks too early to start that strategy, the thought process begins now. For those of you without an AquaSystems moisture probe, talk to your ACS Regional Specialist about what they see in your area. For the rest of you, visit with your FSA about your field and what the best strategy for you is right now.