Nitrogen Fixation in Cover Crops: How to Get Free Nitrogen from Bacteria

0:06 Hi, this is Dale Strickler with Green Kept Receipt. I'd like to talk today about nitrogen. Nitrogen is probably the plant nutrient that's most limiting in most cropping situations. We spend more money on nitrogen fertilizer than on any other plant nutrient, and that's kind of unusual when you think about it because the atmosphere that we breathe, that's above every acre we farm, is 78% nitrogen. There are literally thousands of tons of nitrogen in the atmosphere above every single acre that we farm, but it's completely unavailable to plants.

0:52 Getting that nitrogen out of the air and into our plants is kind of tricky. That's why nitrogen fertilizer is so expensive. The nut bond between two.

1:04 Nitrogen molecules have the strongest bond found in nature. It's a triple bond that is extremely difficult to break. In nature, this bond cannot be broken by plants but only by microbes that contain a certain enzyme. Now about a hundred and ten years ago, a couple of German scientists, Haber and Bosch, found out a process where they were able to use an energy source to break the nitrogen bond through intense heat and pressure and energy, and manufacture commercial nitrogen fertilizer. This was very effective work and made nitrogen fertilizer the only option. However, the problem is it takes a huge amount of energy, and as energy prices go up, this process becomes increasingly more expensive.

2:03 Some also some concerns about what effect commercial nitrogen fertilizer has on our soil microbiology. So there's more and more interest in how can we obtain nitrogen from natural sources rather than having to go and purchase commercial nitrogen fertilizer.

2:20 Historically the way of doing producing our nitrogen has been with by rotating with legume crops or in mixtures of grasses and legumes. And here at green cover see we specialize in cover crops and we have found that there's a lot of benefit to plant diversity having both grasses and legumes and forbs and brassicas all different plant types together. Problem with that is is that legumes tend not to

2:53 Share nitrogen with other plants. They like to use the nitrogen for themselves, and now it becomes available when those legumes die and the nitrogen might become available to the next crop, but they don't share much with the crops. Next up, some nitrogen sure, but not as much as we'd like. Never seems to be enough to maximize the growth of the neighbors.

3:18 What if there was a way that all the other plants in that cover crop mix could also make their own nitrogen? Wouldn't that be amazing? Well, actually, there it is, and the bacteria have got it here. This saves us by room. This is an organism that's very well known to science. It's actually there's more Acer Aspire.

3:42 Element ocula used worldwide than there is the Rhizobium inoculants that we used to inoculate legumes very effective nitrogen fixing organism. Does it produce huge amounts of nitrogen? We will never be able to produce enough nitrogen with our current strains of bacteria to vary 200 additional corn. So this does not replace commercial nitrogen fertilizer, but most of our grass legume cover crop or perennial pasture mixes we're not putting commercial nitrogen fertilizer out there because if you do that it makes the legumes lazy. They will produce their own nitrogen that way. So the niche that this organism and the other organisms that we're going to talk about, the niche that they have is in a

4:34 Mixture of grass and legumes that's not receiving nitrogen fertilizer. There's also some other benefits of the aegis biro. They also produce hormones that increase root elongation. You can see these rice seedlings over here to the right have were inoculated with the additional root elongation they beget. The ether spiral produces auxins that increased root elongation.

5:09 Now this is some research on pasture grass in Israel. Like I said, these are very well researched organisms overseas, very poorly researched in the United States. Doesn't mean they don't work here. It's just that in this country historically nitrogen fertilizer was so cheap, so available, so abundant that we really.

5:33 Didn't pay any attention to these in foreign countries that do not have the fertilizer distribution infrastructure that we have. A lot of interest in these organisms they've been really used like I said more nitrogen fixing organisms put on Azospirillum, Azotobacter, the other organism we're going to talk about more used worldwide and Rhizobium bacteria it goes on the grasses. You can see this is the control on pasture grass, this is the treated see a dramatic increase in biomass. This is an unfertilized condition as a lot of pasture grasses situations are.

6:21 Here's some data from India on sorghum and this is actually grain sorghum probably works a little better on forage sorghum.

7:26 To be a little more productive of nitrogen under optimum conditions but much less reliable. Li is so tobacker is kind of the slow and steady—this is the tortoise. The age of spyro elements the hare, one's a racehorse, this is the plough horse. More consistent, able to survive longer periods of time under unfavourable conditions. When you put the two together you get much more consistent results. A little diversity just like diversity of plant types—there's better results. Diversity of microbes gets better times. Now we have put together an inoculant that combines these two organisms together. Makes we can apply it to cover crops we can apply it to just basically.

8:15 Any crop and turn them into a plant capable of fixing a moderate amount of nitrogen. As we saw in the research, 40 pounds of nitrogen per acre seems to be a top in. I'd say 20 is probably more reasonable. I have used this product myself and I like the results. It's not night and day difference, but it is a very definite visual difference in growth and green in my perennial pastures. Very excited about the possibility of this. It's very cheap—we're talking less than three dollars an acre to apply this. If you can get 20 pounds of nitrogen for three dollars an acre, why not? I mean, to me, it's kind of a slam dunk.

9:07 One thing we do not know is how long these

9:09 Organisms persist in the soil. Whether they will carry over, we know what they'll do on the cover crop. Will they also carry over to the following crop? We don't know, but we suspect there will be some carryover effect, maybe not a hundred percent. Where I really like to use this in addition to perennial grass slingling pastures, sorghum seems to be an exceptional host for this. Longtime sorghum Seban—that's used for forage. Forage sorghum seeds for forage are routinely underfertilized because people are scared of nitrate toxicity. The form of nitrogen these bacteria produce is ammonium. Plants take up the ammonium from the bacteria rather than as nitrate, so this would be safer.

10:01 Nitrogen form than commercial nitrogen, which tends to be converted very quickly in the nitrate in the soil. So I think a lot of times people will plant sorghum Sudan, cowpeas together, sorghum with some hemp or mung beans, a grass legume mixture for better animal nutrition. You can actually turn that sorghum into a nitrogen fixer with these organisms. I guess it's not huge yield impact, not beneficial, well anyhow. This is something we're playing around with. I'm very excited about the potential. It's not going to be huge yield increases, huge amounts of nitrogen, there's a definite benefit as long as you keep your expectations in line with, you know, moderate bump in yield, moderate nitrogen fixation. I think this is product.