Subscribe
Share
Share
Embed
The NDSU Extension weekly podcast In the Pod: Soybean Updates delivers timely insights and expert advice on soybean production.
You're listening to In The Pod, soybean updates, a weekly trek into the latest soybean information from NDSU Extension. Top quality soybeans and higher yields are directly linked to soil fertility. Managing the right mix of fertilizer can be challenging. Brady Goettl, NDSU soil science specialist, has some answers. Brady, here we are in a year with high fertilizer prices. Where should soybean farmers focus their soil fertility dollars?
Brady Goettl:Yeah. When we think about overall soil for fertility, n p k s, those are always the big things top of mind when making soil fertility plans. In the soybean world, really, we only have to worry about p, k, and s. When we think about fertilizing soybeans with nitrogen, there's some folks out there across the state that advocate for 50 pounds at planting. Research across North Dakota, a lot of work was done in Carrington, including surrounding states. It just doesn't show any economic advantage. If you have a well inoculated soybean, which you should be doing, they're gonna fix all the nitrogen they need. That extra 50 pounds or whatever at planting may allow the plants to green up a little bit faster, but it never really pays for itself.
Bruce Sundeen:What about managing phosphorus? Yeah.
Brady Goettl:Phosphorus, when we think about fertilizing corn, nitrogen is top of mind. When we think about fertilizing soybeans, really phosphorus should be pretty top of mind. Our soils across North Dakota are naturally relatively low in phosphorus. We see the levels continuing to decline, but phosphorus is really expensive. Okay, so we don't wanna just throw it out there willy nilly, it's gonna cost us a lot of money. Over the last two years across North Dakota, we actually did a soybean phosphorus rate study, and we actually found that if you have soil test levels that are eight or above Olsen, we're really not gonna see a benefit to the soybean crop by applying more phosphorus. Below eight Olsen, we should apply it. We're gonna see a benefit from that. But keep in mind, a soybean crop is gonna remove a fair amount of phosphorus. So even if you're at that critical level, you won't see a yield bump. You should still probably be putting it on if the pocketbook allows just to build up those levels for future crops.
Bruce Sundeen:What's the story with potassium?
Brady Goettl:Fertilizing soybeans with k is something I've talked about for the last three years. As soybeans continue to move west, we're removing more k from our soils than ever. You know, a good average soybean crop is gonna remove 55 pounds a k per acre, so that's 100 pounds of potash. With the history of not really applying a lot of fertilizer to soybeans, we're removing a lot of k from our systems, and we continue to see these levels decrease across the state, especially in areas where soybeans start moving into what was historically wheat country.
Bruce Sundeen:How important is potassium?
Brady Goettl:It's incredibly important. So for soybeans, yield is very strongly tied to having enough potassium out there. Even And when we start thinking about other crops, potassium is very important for having good seed quality. You know, with soybeans, if you're producing for the commodity market, you know, seed quality isn't the highest concern, yield is. But especially if you start moving into specialty bean markets where protein is important, where oil is important, k is gonna be your best friend for producing that high quality seed.
Bruce Sundeen:Brady, what's the best way to track these chemical elements in the field?
Brady Goettl:Yeah. So with all this talk about fertilizing soybeans and how much you should put on, where you should put it on, really the only way to know the answer to any of these questions is the soil test, and soil test regularly. If you've had a soil test within the last three years for p and k, can we probably rely on that and get some relatively good recommendations. Not so applicable to soybeans, but if you're sampling for nitrogen, that's really something that needs to be done every year.
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 supported by the North Dakota Soybean Council.