
MAX Yield Fertility Plan (Sulphur and Phosphorus)
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Gonna start out today, we’re diving a little deeper into this MAX Yield System‒Fertility Plan. Specifically, we’re going to talk about phosphorus and sulfur, and we probably should call this episode sulfur, because there’s just so many things that we’re learning and experiencing with sulfur these days. Areas where really, it gives us a lot of opportunity to improve our production, improve our plant health, and improve our nutrient uptake all around but phosphorus and sulfur is going to be the main piece of it.
I just want to follow up a little bit, though, on our last episode, you know, we kind of closed out that episode talking a lot about nitrogen. And obviously, nitrogen is, you know, the most widely used fertilizer. The things that we see with nitrogen, you know, we get a bigger, greener plant, typically get higher yields. But the question with nitrogen, I think that everybody asks, because it’s such a volatile nutrient, you know, with its ability, literally, to volatilize off the top of the soil, its ability to leach out of the soil is, how much nitrogen do we need? And how much is too much, and this is a really difficult thing for a lot of growers to grasp. It’s a really difficult thing for crop consultants to grasp. But nitrogen recommendations vary by application timing, by product, by crop, and many other things. And so, I think it’s important to know what you’re doing with nitrogen today, and when you start making changes to that nitrogen system, make them slowly in steps, so you don’t get yourself out of sync to where you see nitrogen deficiency in your crop, or you apply nitrogen in excess. Because excess of any nutrient causes a problem in the soil where we have too much one thing, it can tie up another thing. Or it can create a loss of productivity. It’s something as you try to dial in these programs you want to be careful about how quickly you turn those knobs. And if we’re going to talk about corn, a lot of guys want to know, “Hey, Matt, where are you going with your recommendations?” You know, corn good farming practices in our area, I’m typically looking at like point nine to 1.2 pounds per bushel on your yield goal. And then we’re going to subtract several different credits, depending on what soil test we’re looking at. We might subtract credit for organic matter, and we might subtract the credit for nitrate on that soil test. And then, the other thing we’re going to subtract is we’re going to pull out those pounds of nutrient that we’re crediting to biological sources like Pivot Bio. And so we’re going to come down to a final number. This is our nitrogen rate for this field for the year, through that Max Yield System, through field scouting, we’re going to go out there, we’re going to confirm in season how that nitrogen program is working. You know, there’s always the opportunity to make a little adjustment along the way, bump yourself with some amino acid or some foliar nitrogen in season. You know, to get that last push if you think you have a chance for higher yields, or if you think you’re seeing a little nitrogen deficiency there, that’s all about nitrogen for today.
I’m going to jump back and we’re going to talk about sulfur and phosphorus, and really we’re going to spend some time on sulfur. I want to talk about why sulfur is so important. And I actually started kind of pushing sulfur three or four years ago, more and more, just as our soil test levels continue to show that we’re low in sulfur, a lot of soil tests that I’m pulling these days, and even for last few years, are showing single digit available sulfur numbers. And just here last fall, Certified Crop Advisor sent out an email, it was about a webinar that was titled Sulfur, The Fourth Macronutrient. So we obviously have N, P, and K, nitrogen, phosphorus and potassium as macronutrients. We’ve been taught that. That’s been the lingo of crop fertility for years and years, and now they’re starting to turn around and say sulfur, the fourth macronutrient.
Why is it becoming more important? Well, sulfur is lost in our soils through leaching. And it’s used in our soils in a high amount by our crops. And so, you know, that’s why we’re really seeing these sulfur levels in the soil decrease over time, and then there’s a decrease in the amount of natural deposit of sulfur into our soils. So before the Clean Air Act, we had acid rain, and acid rain deposited a lot of sulfur into our soils for our crops to use. And since the Clean Air Act, we’ve cleaned up pollution in the atmosphere, and we get a lot less sulfur out of our rain water. Now, you know, we need to pay more attention in our soil testing to what our sulfur levels are, and start applying that sulfur through various forms. There’s AMS dry flowable, a lot of guys use it as a water conditioner. It can also be applied as dry for a source of nitrogen and sulfur. There’s also ammonium thiosulfate, or thiazol as most guys would call it, liquid form 12-O-O-26, you’re going to get sulfur through that.
So the question is, how much sulfur do we actually need? And the thing to understand about sulfur is, it’s used by the crop in the sulfate form. And this would be similar to phosphorus, it’s used by the crop in the phosphate form. So, SO₄, sulfate, and phosphate, P₂O₅, the crop uses about the same amount of these two in in the form that they use them. So a pound of sulfate for a pound of phosphate. And so when we look at those soil test levels, we haven’t been paying any attention to sulfur for years and years, we’ve just been using nitrogen and phosphorus. It’s time to really start looking at that sulfur and think about, how much sulfur do we need, how fast can we afford to bring our soil test levels up, and what are we going to get back in return? Well, you know, a lot of the focus has been on phosphorus and starter fertilizer to get that faster growing and greener plant with very little emphasis on sulfur. And so now we’re going to take that sulfur emphasis, and we’re going to talk about why. So sulfur makes your nitrogen use by the crop more efficient. Nitrogen is one of the biggest dollar spends on a crop annually and why wouldn’t we want to make that nitrogen work more efficiently in the plant? This is also one of the keys when we look at what that right nitrogen rate is, if we have low sulfur levels in our soils, and we’re not using sulfur in our fertilizer plan, then we need to increase that nitrogen rate closer to that 1.2 pounds per bushel. If we have good sulfur levels, we can back that off some, because we get that efficiency of the nitrogen and sulfur.
The other thing sulfur does is sulfur buffers the soil pH. You know, we have a lot of lot of high pHs out here in our soils in this area, and pH is above 6.5 and pushing toward 8 in a lot of these soils, 6.5is kind of where you see that sweet spot, micronutrient availability, or just overall nutrient availability. As you push 7 and north of 7 toward 8. You see a lot of those micronutrients are getting tied up in the soil. And so when you use sulfur, you can buffer that soil pH, you can kind of trick that soil into releasing more of those micronutrients than you would typically see if your sulfur levels are low, thats really the things we’re trying to accomplish with phosphorus and sulfur are how do we do this efficiently and tricking that soil pH allowing that phosphorus and micronutrients to be more available is really important. Theres a lot of studies out there talking about soil applied phosphorus only about 20% of the phosphorus that you apply to your soil gets into the plant. The other 80% of it is tied up by something else in the soil, most likely tied up by calcium. And so its like how quickly can we make that change, well we don’t want to make it too fast. Again similar to the nitrogen program, we want to make strides at increasing that sulfur level in the soil so that phosphate and those other micronutrients are available.
So we talked about we need sulfate and phosphate basically in the same level in the soil so that those plants can grow and respond to that fertilizer. We talked about how sulfate really increases the efficiency of nitrogen. And it’s going to increase the efficiency of phosphorus and your other micronutrients as well by buffering that soil pH. I think those are the important things we’ve got to look at as we try to round out that nutrient plan. There’s a lot of micronutrients that we can talk about, zinc, copper, iron, and others, but lets focus on these big ones first and make sure that we have those pieces dialled in, so that when we get to using the micronutrients, which are usually the most expensive nutrients, then we know that what we’re applying is going to get into our plant and going to make a ROI for us, versus just making those applications of nutrients and letting that get tied up in those soils.
That’s all for today. I’m Matt Long. Thanks for joining us on this episode of EZ Ag. Grow your yield. Grow your legacy. Grow strong with Axis Seed, thank you!
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