 Okay, good morning everyone. My name is Audrey Gamble. I am soil scientist for the Alabama Cooperative Extension System, and I'm an assistant professor in the Department of Crop Soil and Environmental Sciences at Auburn. And so today I'm going to be giving a webinar on cover crop systems for specialty crops. I primarily work in the area of row crops or agronomic crops, but I think a lot of the information related to cover crops for row crop systems relates very well. So hopefully this will be beneficial to you all. So to get started, I want to talk about why we plant cover crops. So cover crops are crops which are grown when our cash crops are not actively growing, and we typically are planning them to provide some benefits to the soil. And there's an array of benefits that cover crops can provide, and it's up to the producer to determine which of these benefits are most important to them. So at minimum cover crops typically help to protect against soil erosion and run off of nutrients. They also can help to conserve soil moisture, improve organic matter storage, which is very important for improving nutrient holding and water holding capacity and overall health of the soil. They can also be to press early season weeds. They can help improve water infiltration, provide supplemental nitrogen, in the case of legumes. They can scavenge for nutrients and break up soil compaction. So today I'm going to be going over just some basics of implementing cover crop systems, and as I go along I'm also going to try to point you in the direction of additional resources that you can use to get more in-depth information. So this is kind of my outline for the presentation. First I'm going to start with how we select cover crops to sit in with our cash crop rotation. Then I'm also going to go through some basics of cover crop planning and cover crop management as well as cover crop termination, and lastly planning into cover crop residues. So to get us started about thinking how we're going to select our cover crop species, I first want to talk about the amount of residue that a cover crop can provide, because the amount of residue or biomass that a cover crop provides is very important for achieving certain goals. So as I mentioned before, even at low levels of biomass as seen in these first two pictures here, we can at least help protect against erosion and nutrient loss to an extent. We can also help with water infiltration. But some of these other benefits that we achieve through cover crops such as increased organic matter storage and suppression of weeds actually take very high levels of biomass. And so it's important for producers to think about what benefits they're trying to achieve as they select their cover crops and decide how they're going to manage their cover crops. So these are some of the considerations that I think are very important for cover crop selection. And typically the first questions I would ask a producer if they may be asking for advice on which cover crops to implement. So the first question is somewhat obvious, but what cover crop planning dates work with your crop rotation? Obviously if you're using, if you're planting summer cash crops, you're going to implement a winter cover. And conversely, if you're planting a winter cash crop, you're going to be looking at summer covers to implement. And so but we can get a little bit more specific with that too and I'll talk about that in coming slides. One of the most important considerations is what benefits are am I trying to achieve? I have a picture above this here of a brassica. Brassicas have a deep tap root which can go and scavenge for nutrients deeper in the soil profile and bring them up. They also, certain brassicas have the ability to suppress certain nematodes and so in plant parasitic nematodes specifically. So these are some of the considerations that you may have is what are you trying to achieve with a cover crop? And then lastly, what cash crop will follow in my cover crop? And so this is important because certain covers can actually negatively impact the growth of a cash crop and that's not what we want. So for example, if we're growing a legume cash crop, we don't want to plant a legume cover crop before that cash crop because planting a legume in rotation with a legume can promote disease cycles and it can also inhibit those rhizobacteria that help legumes fix their own nitrogen. And so that's a specific consideration. And then in certain cases, there can actually be allelopathic effects of a cover crop residue on a following cash crop and that just means that the plant itself may cause harm to the following cash crop. So an example of that would be planting corn following ryegrass. Ryegrass as opposed to cereal rye has an allelopathic effect on corn and so those are some considerations as well. So kind of going back to that first question of what cover crops work with your crop rotation. These are some typical planting dates that we would use for fall and winter cover crops. And this is taken from the Southern Cover Crops Council, which I'm a board member and I'll point this out in future slides, but this is a great place to go for additional information on cover crops. So we put together these planting guides for dates at which specific cover crops should be planted. You'll notice that a lot of our winter covers such as oats and rye, they do best when planted particularly in October and then can be beneficial as well in November. But as we start to move down to our brassicas like daikon radish, these really have to be planted a good bit earlier in order to really produce. So brassicas like daikon radish like to be planted as early as August and on 30th September and once we get into November in Alabama this is typically too late to plant brassica. This is the same type of graph but showing early spring and summer planted cover crops. So again most of these covers you can plant them in May and June. This includes our summer grasses like millet and sorghum sudangrass, legumes like cow peas and sunhemp and some of our broadleaves. But these same species can some of them can be planted through August whereas others such as cow peas we sorry such as buckwheat we may not want to plant that late. So the next consideration when it comes to cover crop selection that I mentioned was what benefits are you trying to achieve and we can kind of group cover crops into these three categories when we're thinking about benefits. The first category and our most prominent category as far as cover crops planted in Alabama would be small grains such as rye and oats when we're thinking about winter cover crops or millet and sorghum sudangrass when we're thinking about summer cover crops. These are excellent at producing a very high biomass especially when they're planted in a timely manner. This high biomass can serve to help with weed suppression in the early season, conserve soil moisture and improve soil organic matter. They also of course can help with nutrient scavenging with their root systems as well as help prevent erosion. Legumes such as clovers, betches, sunhemp, these are are excellent for fixing nitrogen for the subsequent cash crop and brassicas or other broadleaves. Some examples being brassicas being radish and canola. These have deep tap roots and in some cases they can help to break up soil compaction and they can also scavenge for nutrients deeper in the soil profile. And this is just to go a little bit more in depth with the legumes. This gives an example of nitrogen production per acre. So a lot of our clovers, betches, they'll produce approximately 150, 100 to 150 pounds of nitrogen per acre depending on the stand that you have. Of course not all of that nitrogen is going to be available to the subsequent crop but we can typically get about a 30 to 50 pound nitrogen credit on the subsequent crop per acre when we follow their legume. A very obvious consideration when selecting cover crops would be where you can get seed. So we we have on the southerncovercrops.org website. We have some seed sources listed by state. You can see we have a few listed in Alabama. If you have any that you would like to add to this list please feel free to contact me. I'll provide my contact information at the end of this presentation. But you can go to this website to access websites and phone numbers for some of our local seed sources. So moving on from cover crop selection to cover crop planting. Cover crops can be planted in a variety of ways but the most uniform stand is going to be provided with the drill because that ensures good seed to seed to soil contact. We can also broadcast seed on top of the soil surface but we're typically going to have to increase seeding rates by approximately 20 to 50% when we broadcast. So on the southerncovercrop.org website we do have information sheets for each for a variety of cover crop species which tells seeding rates or drilled planting as well as recommended seeding rates for broadcasting as well as seeding depth and some additional information on those specific cover crops. And we also have resource guides for setting up and calibrating drills and spreaders and this is the link to find those. This is just an example of the types of information sheets that we have. So in this particular case I selected the information sheet for cereal rye. So you can see we have some information about specific varieties. We have planting information including depth seeding rates and then we also have some information on how to terminate that cover crop and just some some of the specific traits of that crop and such as the relative cost, the typical amount of biomass that it produces and some specific cautions that you may need to follow. So these are an excellent resource for finding out information about a specific cover crop and also whether the specific cover crop will provide the benefits that you're trying to achieve on your farm. Moving on to cover crop management I want to briefly cover fertilization of cover crops. For pH phosphorus and potassium we're going to want to maintain soil test recommendations. So of course you can always take a soil sample and send it to the Auburn University soil testing lab to determine that. Typically as long as we're maintaining our pH phosphorus and potassium for our cash crops they should be an adequate supply for our cover crops. However when it comes to nitrogen we're going to have some different considerations. So nitrogen management is going to depend on the type of species as well as the amount of biomass that you're trying to achieve. Specifically with small grains which we're often planning for that high biomass we may have to supplement some nitrogen. So supplemental nitrogen of 30-50 pounds will be necessary typically to get that additional biomass and if we delay planting past the optimum window we may even have to apply more nitrogen to meet our biomass goals. And so this graph that I'm showing here this is some research that was done at the U.S.D.A. soil dynamics lab in Auburn, Alabama. It just shows rye biomass according to nitrogen rate and this was done at one of our research stations in Alabama and it's showing here in the red line we can see early to mid-December planting dates for rye and then we have in green mid to late November in yellow we have early to mid November and in blue we have mid to late October. So you can see the earlier we planted our rye the more biomass we achieved but we were able to make up for it a bit when we put out nitrogen. But this highlights the importance of getting your cover crop planted in a timely manner so you don't have to add more cost to your system by applying more fertilizer. So here when we compare an early to mid December planting date to the mid to late October planting date you can see it took us 90 pounds of nitrogen to achieve approximately the same amount of biomass that we achieved with no nitrogen at our earliest planting date. So again you can can work around your nitrogen, nitrogen rates according to how much biomass you're trying to achieve and when you planted and that applies to our small grain covers. When we have a legume in a mixture we typically do not need to apply that additional nitrogen as long as we have approximately 30 percent sand cover of our legume cover crop. So it is important though to make sure you inoculate legume seed this helps promote nitrogen fixation and you can look up for instance on those fact sheets what specific inoculant is needed for a specific legume. Moving on to cover crop termination so termination is just when we kill the cover crop in preparation for planting of the following cash crop and timing of termination is it's critical for optimizing that biomass production. We want to allow enough time for our cover crop to grow to really produce a good bit of biomass typically but we often want to terminate two to four weeks prior to planting to help ensure that we have good soil moisture since actively growing cover crops can deplete soil moisture and this also helps to prevent nitrogen immobilization which is important with small grain. So when we have a lot of small grain residue on the soil surface it has a high carbon and nitrogen ratio and it actually can tie up the amount of nitrogen or it can tie up nitrogen as we apply nitrogen for our cash crop and terminating ahead of time can reduce the risk of some insect pests as well as seedling board diseases. There are producers who are able to plant into standing cover crops or plant terminate directly at planting or right after planting. However we recommend that if you're attempting to do this you start out on a very small area because it is a little bit more risky to terminate that late in the season just because of these these reasons that I have listed on this slide but there there can be some benefits to that but but we suggest that if you're interested in terminating you know right at planting or planting into an actively growing cover that you do that on a very small area or acreage to to try that out and make sure you can learn to manage it appropriately. There's several different methods for termination and I'm gonna go through three of those right now. Chemically terminating means that we're spraying with herbicides and I don't have time to go through specific herbicides to use or tank mixes to use for specific cover crops but we do have information about that on the southerncovercrops.org website I've got the link to that here so you can check that out. The advantages of chemical termination are that we can leave the residue on the soil surface and this is very important when we're trying to achieve weed suppression and improve soil moisture storage in our fields. So additional options for terminating cover crops is roller crimping and you can you can also crimp without that shouldn't actually not say whether without rolling but rolling and crimping is another method to terminate small grain cover crops specifically. When it's not as easy to kill legume covers or our broadleaf covers through rolling and crimping and it often takes three to four passes with a roller crimper to kill those those covers but small grains as you can see in this top picture here this is a picture of a roller crimper it's just basically a bar that has these kind of blades soldered on to them that will cut into not actually cut through the cover but will crimp that cover and kind of kill the vascular or cut into the vascular tissue and prevent that crop from continuing to grow but again this is is not as effective for legume cover crops so when crimping small grain we typically crimp at soft dough stage or later and soft dough is kind of intuitive it's when that grain that's being produced when you push into it with your fingers that it kind of feels like a soft dough and the ground should not be soft at the time of rolling and crimping because in order to to crimp into that residue we need to have a little bit hard ground in order to effectively crimp. Mowing and incorporating is another option for cover crop termination and this is more frequently used in organic systems this when you're when you're mowing and incorporating there's some considerations so cover crops are easier to kill with mowing when they've reached maturity whether that be you know grain fill with a with a small grain cover crop or full bloom with a legume cover it's easier to kill them when they're at maturity and mowed cover crop residue should be incorporated with tillage as soon as possible but you want to keep in mind that you you don't want to have more residue than your tillage equipment can handle turning under the soil so that's a specific consideration for mowing and incorporating. So mowing and incorporating it has has the advantage of the you don't have to use chemicals to terminate but then you don't have that residue on the soil surface to help with with moisture storage and wheat suppression. So moving from termination to planting into your cover crop residue these are just some considerations for setting up your planters of course when you have a residue that hasn't been turned under and you just have it laying on the soil surface in order to plant through that you're going to need a sharp culture to ensure that residue is cut and doesn't wrap with whatever type of planter you're using. So I've got a picture here this all this is a on the bottom here we've got a no-till vegetable transplant and it has cultures that are cutting through the residue that's shown in this photo in order to to create an area that we can get good seed to soil or transplant contact with the soil. Also important cultures going back to cultures these perform best on firm ground so anytime you're using culture to cut through residue you want to avoid try to avoid that wrapping so put it far enough in front of any tillage conservation tillage equipment to avoid that. Wheel cleaners are also important to help ensure seed to soil contact these basically just sweep residue out of the way as you're planting you can see a picture of that on this top picture here this is a row cleaner that just kind of sweeps that residue out of the way while planting and it's also important to maintain correct down pressure and use closing wheels so that you can if you're planting seed that you can ensure seeds of soil contact as those wheels press back down and you can't see it in this picture here but there's actually some closing wheels on this vegetable transplant or that helped to kind of put pressure on the soil around around the transplant. So that's a brief introduction to cover crops for more information I've mentioned several times the website southern cover crops.org again this is a group of scientists university scientists government scientists farmers from throughout the southern region of the United States who put together information we have this is some examples of fact sheets such as how to terminate herbicides how to ensure good seed to soil contact should you fertilize your cover crop we've got a little schematic for that so I encourage you to check this website out another website will is alabamasoilhealth.org this is on the Alabama Cooperative Extension System website and it was sponsored by the Alabama School and Water Conservation Committee so we've actually tried to put together some information on just on soil health and how cover crops can improve soil health on this website we've also tried to put all of our research related to cover crops both from Auburn University and Extension as well as the USDA soil dynamics lab and we tried to update research on here and we have it divided into row crops specialty crops and pasture and hay soil conservation and so there's some some information on cover crops on here as well so that's all I have today thank you if anyone has any questions please send them to agamble at Auburn.edu I've also listed my phone number here so again thank you for for your attention and I hope you all have a good day