Augustine Obour on Soil and Nutrient Management

(Augustine Obour) My name is Augustine Obour, the soil scientist out here in Hays. I’ve been with K-State for about three years. Most of what I do is soil and nutrient management in dryland systems. Some of the projects that we’re working on are looking at different tillage systems and nitrogen fertilizer management; and how that affects crop production; and nitrogen use, efficiency and things like that. So over the years, we’ve been seeing there’s been a lot of adaptions, moving from conventional tillage to reduced kind of tillage or strictly no-till systems, and that is very good; reducing tillage intensity helps to improve soil quality and also reduces specifically runoff from erosion. And the wind erosion is significantly reduced where you have no-till or reduced till systems and that tends to improve the soil quality. Now we’ve seen problems with glyphosate resistant weeds. So people are now reverting back to conventional tillage to take care of this weed issue. And that is our big concern. One of the things that we are trying to do is to put in something like cover crops. Planting cover crops in dryland systems to try to suppress some of the weed issue. We have been seeing some good results from our work in the cover crop work we are doing, like we are doing in Colby, and our ranch. But we’ve seen when you grow cover crops in the fallow phase, we suppressed weeds very significantly. So this could be a way forward, trying to reduce some of these glyphosate resistant weed issues that we are seeing in our dryland system. We’ve seen that, if you have too many species mixes you don’t have more biomass compared to where you have a simple kind of cover crop mix. Where you have just grass mixes, where we have oats and triticale mix or we have oats, triticale and pea mix does better than when we have oats-triticale-buckwheat-radish mix, that’s kind of—if you have too many species mixes you have cost—the seed cost is higher. But if you have only simple mixes, the cost is significantly lower. What we did last year, we just planted the cover crops in the spring. We didn’t spray anything; we just came back and killed the cover crops in June. And then we came back in October and planted our wheat. We didn’t spray anything. We sprayed just once to kill the cover crops. And most people were saying, it’s the same thing, you may spray once to end the cover crop or you spray like twice. You ended the cover crops, weeds come up, and you spray again. But on the other hand, we spray like three times to take care of the weeds. And even at some point, some of the glyphosate resistant weeds were not dying we needed to mow them down, we just have to mow it. So in terms of cost, I think the cover crops is relatively—I think in terms of the cost compared to using herbicide sprays several times, the cover crops may be cheaper. Yes, in addition to just growing the cover crops just for cover, we are looking at different management systems where you can use the cover crop for forages. Where we graze some of the cover crop or we hay in it or just as hay. So we have oats and triticale that we plant in March, and then we come in and graze it towards the end of May or early in June for the grazing. And then, we have the simple hay. When it hays out, then we go in and swath it for hay. And what we’ve seen is, if you grazed it, you reduce some of the biomass for the cover for the grazing. So what you have to do is try to—you don’t have to graze everything, you can graze and leave close to about 50% of the biomass in the system. Then when you’re harvesting it for hay, you try to cut it a little bit higher, taller than when you do normally for hay. So we cut in just about six inches high so that we can leave a lot of residue in the soil.

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