 All right. Good morning. Thank you everybody for tuning in to the animal science and forage webinar series this morning this morning Our speaker is dr. Audra Gamble Dr. Gamble is our extension soil scientists in the Department of crop soil and environmental sciences And today she's going to be talking with us a little bit about graze cover crop systems and some of the work that we have going on In Alabama related to this topic. So with that, I'll go ahead and turn it over to dr. Gamble All right. Thanks, Kim. Um, today I'm going to be talking about graze cover crop systems and specifically I'm going to focus on winter annual forages which are planted into row crop production systems. But much of what I'm going to cover will also be relevant for any winter annual forage production systems or in some cases, maybe even summer annuals. So I want to get started just by talking about what exactly a cover crop is and how we use that term to distinguish from a more typical winter annual production System and so cover crops or crops which are grown specifically to provide some sort of benefit to the soil. And so At minimum cover crops are going to help protect against erosion and nutrient loss. So when we plan to cover instead of leaving soil bearing That provides a mat to protect the soil against erosion when heavy rainfalls come or strong wind storms come Cover crops can also help with improving water infiltration scavenging for nutrients and improving nutrient cycling. Um, in the case of legumes. They can provide a source of supplemental nitrogen and they can help break up soil compaction conserve soil moisture increase organic matter storage and suppress weed growth, all just depending on what types of cover crops you're using and how you're managing that cover crop. And so many of those benefits which I just listed For cover crops are related to the amount of biomass, which is left on the soil. Once another crop is planting. So, so again, When we have even low levels of biomass that cover can help to protect against erosion and nutrient loss. But as we increase the levels of biomass that can help with some of these other benefits like increasing organic matter storage. Conserving soil moisture and in cases where we have a very high amount of biomass of about 8,000 pounds of dry matter per acre or greater. We can help with suppressing weed growth. So this is particularly important to think about, especially when when cover crops are going to be grazed because we want to weigh out the benefits that we're trying to achieve. In terms of soil health with those that We're trying to achieve in terms of a forage production. So I'm going to cover several different topics today, but I'm really going to just scratch the surface on these topics, including cover crop selection cover crop planting. Cover crop management termination and then planting into cover crop residue, but I'm going to try to provide some some links to more in depth information. So that any of you who want want some more in depth knowledge about any of these topics. You have somewhere to look for that. In most of those links, which I'm going to provide are going to be on the southern cover crops.org website, which is put together by the Southern cover crop Council, which is a group of scientists from throughout the southeast. Including myself and Kip Balkum, who is a agronomist with the USDA soil dynamics lab here in Auburn, and then I'm also going to provide some links to information on the alabama soil health.org website, which is an Alabama Cooperative Extension System website where we have tried to consolidate information on cover crop research from Alabama. So to get started, we'll talk about cover crop selection. This is very important for producers to think about ahead of time. Again, so that you're not only considering the benefits that you want to achieve in terms of forage production and forage quality, but also the benefits to the soil. So small grains such as rye and oats are going to be excellent for putting on really high levels of biomass, which can help With some of those benefits like improving soil organic matter scavenging for nutrients and improving water infiltration legumes are excellent to include to help provide some supplemental nitrogen to crops and brassicas. Such as radishes and turnips. They have been shown in certain soil types to break up soil compaction with their deep tap roots and also scavenge for nutrients deeper within the soil profile and improve water infiltration. So these can be used, obviously, by themselves or in combination with each other to provide an array of benefits and also increase the grazing season. So with a mixture of Different species of cover crops. We may be able to extend that grazing season since crops like brassicas and small grains tend to put on some growth early in the winter, whereas legumes, it may be spring before we start to see some pretty substantial growth out of those crops. This is just to highlight the legume nitrogen production. Some of our winter annuals like crimson clover and hairy vetch can provide about 150 pounds per acre of nitrogen to the soil. And that nitrogen can help cut back on your cost for the crop. If you're using a mixture of cover crops such as maybe a legume with with Ryan Oates or something like that. And depending on when that crop is terminated, it may also be able to provide some some nitrogen to the subsequent cash crop. The last thing that I'll say about cover crop selection is know what herbicides were applied during the previous cash crop growth and check your pesticide levels to ensure that no herbicide residual activity is going to affect the growth of the crop. The last thing that I'll say about cover crop selection is know what herbicides were applied during the previous cash crop growth and check your pesticide levels to ensure that no herbicide residual activity is going to affect the growth of any forage species species, which are going to be planted. You don't want to buy seed only only to have it a poor stand from herbicide residual activity. This is a graph which we have on the Southern crop Council website showing optimum planting dates for various cover crop species, as well as the timing of when the rapid rapid growth is going to be put on. So we're getting on into October at this time and it's very important that especially for our brassicas and even our legumes that we try to get those planted as soon as possible because they really need to be planted by October to put in on substantial growth for the most part. Our grasses such as oats and rye can continue to be planted on into early December, but as I'll discuss a little bit later, the growth is going to be improved if you can get those crops in earlier. This chart also highlights how planting different cover crops can help extend your grazing season. You can see that brassicas, they're going to put on growth early. Even as early as December and January, you're going to start seeing substantial growth out of some of those crops, whereas the legumes are going to be putting on more growth in the spring. So a combination can help with extending that grazing period. When it comes to planting cover crops, drills are obviously going to provide the most uniform stand because we know we can ensure good seed to soil contact. For broadcasts, we're typically going to need to increase whatever our recommended seeding rate is for drilling by about 20 to 50%. Aerial broadcasting is another method that can be used to plant cover crops and ensure that we get them in early, but this tends to work best for small grain and brassica cover crops. And for any broadcasting, we really need to make sure that we've got adequate moisture when planting. I've got some links provided here to the Southern Cover Crop Council website. We have some information sheets that show seeding depth, seeding rate, variety, preferred varieties for some different cover crop species. I have an example of that on the next slide. And also we have on their resource guide for setting up and calibrating drills and spreaders. So if that's something you're interested in, be sure to check out the Southern Cover Crops website. This is an example of cover crop information sheet that's available. You can see that we have some varieties and the benefits of some of these different varieties as well as sources for seed, in addition to seeding depth, seeding rates for various planting methods. Of course with our cover crops, just like any crop, it's very important to make sure our fertility is managed to get optimum growth. We want to maintain our pH, phosphorus and potassium according to soil test. And nitrogen, there's a lot of considerations for nitrogen when we're thinking about cover crops. And that really depends on how much growth you're trying to achieve. So for maximum production of small grains or small grain ryegrass mixtures, apply up to 100 pounds per nitrogen per acre at plant. And that's as high as you should be going. And that's a little on the high side even. So you can reduce this if less than maximum production is required, or if a legume has just come out of rotation, or if you planted early. I've got a slide here from Dr. Balkum at the USDA Soul Dynamics Lab showing the effect of planting date and nitrogen rate on rye growth. And this is from a study that's been done at the Wiregrass Research and Extension Center for the last few years. So you can see here on this graph, we have in blue rye that was planted in mid to late October. And in red, we have rye that was planted in early to mid December. And for that mid to late October date, we can produce as much rye biomass without any nitrogen, just about as we can for rye that was planted in early to mid December with 90 pounds of nitrogen. So again, planting early is very important for getting growth and you can potentially cut back on your nitrogen for grazing grazed forages if you're able to plant early. We're typically going to want to add some additional nitrogen in late winter, early spring to maximize production if our cover crops are being grazed. But if you've got a grass legume mixture, no additional nitrogen is going to be needed if you've got about 30 to 50% of the stand at least, which is legumes. And my last note on fertility is be sure to inoculate legume seed prior to planting of legumes. Different legume cover crops are going to require different inoculants. So be sure that you have the appropriate inoculant in those cases. And just kind of going back to this, this diagram that I had on biomass production of cover crops and benefits from cover crops. When we're grazing, we've got to think about, you know, balancing animal production benefits with soil benefits, and that's going to be up to the individual producer to determine. So if we're trying to achieve some of these benefits such as increased organic matter storage and conservation of soil moisture for the next cash crop, we've got to allow some adequate growback time to maximize regrowth of that biomass. So that's that's one consideration as far as grazing management on cover crops. So seasonal grazing is going to be very important for, you know, preventing severe compaction, as well as distributing nutrients evenly across the field. Both of these are going to be an important for production of the next cash crop that's grown. And it should go without saying that we don't want to overgraze our cover crops. We're planning cover crops specifically to provide some benefits to the soil. So when we're overgrazing, we're reducing that soil coverage and increasing potential for erosion and nutrient loss. All right, moving on to cover crop termination. We typically recommend terminating cover crops approximately two to four weeks prior to planting, because this helps to ensure good soil moisture and recharge of soil moisture. So if we have a cover crop which is actively growing just before cash crop planting that can be actually taking moisture that that a newly planted crop needs away. Terminating early also helps to prevent with nitrogen immobilization, which is particularly important when we have small grains, because small grains have a high carbon and nitrogen ratio which can tie up nitrogen. So terminating early that helps prevent immobilization of nitrogen and in terminating two to four weeks prior to planting also helps to reduce risk of some of our insects and disease issues. Methods for termination. Typically we're going to be talking about chemical termination. So we have some suggestions here for chemicals for terminating covers. Most of our small grains with exclusion of ryegrass can be easily terminated with glyphosate, legumes. We may have to tank mix glyphosate with something like glufosinate or to 4D same with brassicas, but be sure to check your pesticide labels and ensure that herbicide residuals will not interfere with the growth of the next cash crop. So if you are interested in getting some more information on chemical termination of cover crops, there is a link to a fact sheet on the Southern cover crop council provided here. Planting into cover crop residue. It's been shown and Dr. Kip Balkam who's on with us right now, he's had research projects which has shown that cash crop yields following grazed cover crops. They tend to be best when we have some kind of non inversion tillage. And when I say non inversion tillage, I mean tillage which does not turn the soil, but instead till is only in that area where crops are going to be planted. So strip. And so, you know, we, especially after after cattle grazing, we want to ensure that that compaction is not an issue. So strip tillage and subsoiling is our good options for helping to prevent that. So I've got a link here to a fact sheet from the USDA IRS thing, which discusses some of the adaptions that may be necessary to conservation tillage equipment or planters when planning into heavy residue. So first we're going to want to make sure our cultures are sharp so that we can cut through any of the dry residue that we have left, so that it doesn't wrap up around our equipment and, you know, form little piles in places because that affects our crop stand. So planters are necessary, especially in high residue systems to help and ensure seed to soil contact. So I've got a link here to a video from our friends at the University of Georgia, which shows some information on setting up planters to plant into a heavy cover crop residue. Okay, so the last thing that I want to go through is just some current research that we have going in Alabama related to graze cover crop systems, myself, Dr. Kim Mullen X, Dr. Kit Balkam, Dr. Leanne Dillard, Rishi Prasad, and Dr. Yu Chung Fung are all involved in. So this is a trial that we have established at the Wiregrass Research and Extension Center in a cotton and peanut rotation where we have planted some, a cover crop mixture of rye, oat, crimson clover, and T. Raptor Brassica, which is a turnip-rape seed hybrid. And we're looking at both animal production and effects on soil health within this graze cover crop system. So we're finishing up our first year of this four-year study right now. We're planning to harvest cotton this week. So within this trial, we have grazing paddocks, which are replicated, and we have treatments with without any grazing, and then grazing with cattle removed in mid-February, grazing with cattle removed in mid-March, and grazing with cattle removed in mid-April. And so our goal with this is to look at what type of cattle removal dates are beneficial for both providing, optimizing, I should say, our cattle production as well as benefits to the soil health. And so this is results from the first year of the study in terms of how the forage species composition within our mixture changed throughout the growing season. So for these covers, which were planted in late October, you can see that by mid-January, about 70% of our biomass was contributed by grasses, small grains, about 10% from clover and 20% from our brassicas. The brassica contribution to biomass stayed pretty consistent throughout our growing season. The contribution of small grains declined, and the contribution of clover increased up until we terminated in early April. And so you can see, again, some of these benefits of including mixture for extending grazing seasons. This slide shows the grazing length for our different treatments. So when we removed cattle in mid-February, we were able to have a grazing season of about 32 days. So we started grazing in early to mid-January. Then for our mid-March timing, we had 46 grazing days, and for mid-April, 65 grazing days. Our biomass, when we stopped grazing in mid-April, is shown in this table as well. So you can see that in our control where we had no grazing, we had about 7,000 pounds of dry matter per acre at termination. For our mid-February cattle removal date, we had about 4,000 pounds of dry matter per acre. For mid-March, about 3,000 pounds, and for mid-April, about 2,000 pounds. So we had the longest grazing season for our mid-April treatment, but also the least amount of grow back time allowed there. So this graph was made by Dr. Kim Mullenek showing average daily gain according to treatment. Of course, you can see that our average daily gain in animal performance was greatest for the mid-April cattle removal date. But again, this removal date also had the lowest amount of biomass remaining. So right now we're in the process of evaluating many of the soil health or soil quality benefits associated with these different treatments. So we're looking at factors such as organic matter storage, nutrient cycling, microbial biomass. And so stay tuned on some of this continued research to determine how these grazing treatments are impacting soil health. We'll also be looking at cash crop yields as well, so we'll have our first year of data on that soon. So be sure and stay tuned to us to get some more information on this study. So that's all I have today. If anyone has any questions, I'll be happy to take them at this time.