Keeping an eye on fertility inputs and steps to fight Iron deficiency chlorosis are covered with Brady Goettl, NDSU Soil Science Specialist.
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Keeping an eye on fertility inputs and steps to fight Iron deficiency chlorosis are covered with Brady Goettl, NDSU Soil Science Specialist.
What is In the Pod: Soybean Updates?
The NDSU Extension weekly podcast In the Pod: Soybean Updates delivers timely insights and expert advice on soybean production.
Bruce Sundeen:
You're listening to In the Pod, Soybean Updates, a weekly trek into the latest soybean information from NDSU Extension. Top quality soybeans, along with higher yields, are directly linked to soil fertility. How does a farmer achieve these basic goals? Brady Goettl, NDSU soil science specialist, has some answers. Brady, here we are heading into a year with high fertilizer prices. Where should farmers be focusing their soybean fertility efforts?
Brady Goettl:
When we think about managing soil fertility in North Dakota for any of our major crops, it's really nitrogen, phosphorus, potassium, and sulfur are the major nutrients we look at. When we're dealing with soybeans, nitrogen just isn't needed. Some people in the past have advocated for small amounts of nitrogen at planting to increase yield, but our research in North Dakota and across the North Central Region shows it's really not an economical addition. So this year when prices are high, maybe avoiding that nitrogen application to maximize our profit. Phosphorus, on the other hand, is only needed in low soil testing level soils. So phosphorus below eight eight parts per million, broadcast P will be profitable. Above that, we're probably not gonna see an increase in yield. Potassium is probably becoming one of the most important soybean nutrients. K levels in North Dakota have been decreasing fairly steadily over the last decade, And we have to remember, an average soybean crop removes about 55 pounds of k two o per acre. So that's a hundred pounds of potash. Any field that has a soil test k level below 150 to 200 parts per million depending on your region, check out our NDSU soybean recommendations for more information on that, we should be applying K to not only build up our low soil test levels, but also to compensate for what's being removed by that soybean crop. Sulfur is the last nutrient we need to majorly think about in soybeans, especially if we're expecting a sulfur deficiency. Soil tests for sulfur really aren't that useful and probably aren't going to be reliable for making recommendations off of. Just a flat rate of 10 pounds of sulfate sulfur per acre should be more than enough to make up for what that soybean needs and especially we should think about applying that sulfate sulfur if we have a wet spring, if we're in a sandy field, or we have low organic matter. All of those factors are going to cause potential sulfur deficiencies.
Bruce Sundeen:
Iron deficiency chlorosis or IDC is a big problem in North Dakota. What kind of management strategies should farmers be thinking about?
Brady Goettl:
When we think about major soybean problems that we have throughout the year, iron deficiency chlorosis is really at top of mind. And I think the biggest impact that we can make for reducing the amount of IDC we're gonna have in our field is really coming from field and variety selection. So choosing soybean varieties that are resistant to IDC is going to be our first line of defense against yield reduction. The second thing is looking at field selection. So we know that fields that are very calcareous are going to have a high IDC risk, and that's going to be exacerbated by wet conditions in the spring or high electrical conductivity. So, managing your fields in order to reduce water logging, to reduce EC, is going to help over the long term reduce IDC risk. In the short term, if we have a field that's really high in nitrate, that can also exacerbate IDC risk. So, we know that soybeans don't need extra nitrogen, they're a legume, they're gonna fix their own. If we have a field that's very high in nitrate, consider planting a high end demanding crop. You know, we can use that nitrogen that's in our field already in a more economical way while at the same time reducing IDC risk. Another good tool in our toolbox for managing IDC in North Dakota is using chelated iron, but we have to remember that this is a good tool and not a silver bullet. Using chelated iron with other control practices, including variety selection and field selection, is gonna help to reduce IDC risk. The best chelated iron we can use is going to be in the ortho ortho iron EDDHA form to be the most effective. There's a few other cultural controls that have been used in North Dakota with varying degrees of success, including increasing plant density. So if we have more soybean roots close together, they can help overcome that calcareous soil in a way that then the plant is able to take up more iron. Also, using a spring nurse crop or cover crop can help to firstly reduce the amount of water in a potentially waterlogged field reducing that IDC risk, also take up some of those nitrates in addition to having that living root in the soil then helps make more freely available iron.
Bruce Sundeen:
Thanks, Brady. Our guest has been Brady Goettl, NDSU soil science specialist. You're listening to In the Pod, Soybean Updates, a weekly trek into the latest soybean information from NDSU Extension.