Transcript for:
Establishing Alfalfa and Grasses for Hay and Silage

hello I'm doctor Dan under sander extension research forage agronomist with the University of Wisconsin and we're going to talk today a little bit about establishing alfalfa and grasses for hay and silage the first thing to consider when establishing stands is that we need to have the right soil pH we need to have a firm soil and we need to place at the right depth low soil pH loose soil and improper seeding depth are responsible for about 90 percent of the stand failures that we have in alfalfa and grass establishment we do recommend a soil pH of 6.8 when we get lesser PHS we will have slower establishment and poorer stands the other thing is is seating depth a lot of our alfalfa seeded with a brilliant cedar and then depth is not an issue because we're distributing on a packed soil and then punching it into the soil a little bit but as we're using more and more drills for seeding depth and seeding too deep becomes a major issue what this graph shows is that our recommended seating depth which is a quarter to half an inch is fine it will give us the best stands it'll give us a little bit of ground cover it'll hold the moisture in place as we go deeper than a quarter of an inch particularly on the sands and the Clay's what you see is that the establishment declines very rapidly with seeding depth and so this is one of the examples that kinds of things that we see in the field where you see a row that came up just fine and right next to it on either side is a row that did not come up that means that one disc opener was putting a seat at the right depth and the disc openers on either side we're putting the seed either too deep or too shallow so seating depth is a key issue we need to with drills have depth fans have them properly adjusted the other thing that we need for getting a good stand is a firm soil when we put that seed in the ground we need to pack the soil against it so that that seed can absorb water from the soil if the soil is loose that means there's too much airspace that means that the seed does not contact the soil and the seed will not take up the water so here's an example of a field where the soil was not packed and you can see that in this case the grass came up fine where the wheel lugs of the tractors were where there was a little additional packing of the soil and we got absolutely no stand in between the only difference being how loose or tight that soil was so again the three major causes of stand failure are low soil pH a loose soil and improper seeding depth of we're using a grill if we could overcome those in most cases we would get good stands nothing works all the time but we would get good stands most of the time and I would strongly invest that as you or your clientele are working with fields that you suggest proper seeding equipment proper adjustment too often we use old equipment that isn't properly repaired isn't properly adjusted and then we end up with stands like we've seen in the previous pictures now let's talk a little bit about the germination process alfalfa is a kidney-shaped seed you actually don't see this so much anymore because most of the seed that is sold is coated with a clay or polymer coating and that polymer coating holds the inoculum it holds in some cases usually fungicide one or two and in some cases some minerals and and other products such coating is is actually in most cases beneficial to the seed and would be recommended we need to keep in mind that there are two distinct lines of coding the standard clay coding is about 32% of the weight the polymer coatings can be as low as eight to ten percent of the weight you can tell what you have by looking at the tag on the bag and the inert material would be largely the seed coding so in one case you might have 32% inert material in your bag and in the other case you might have eight or ten percent inert material look at the seed tag on the bag to determine how much pure seed you have and what the germination is now as that seed begins to germinate the first thing that it does is pick up water and if you have good seed soil contact and then that seed swells in size and then that seed coat cracks as you see here on the bottom and that water uptake is called imbibition so the twenty five cent word for the day is imbibition water uptake by the seed coat now one of the challenges that we can run into is that we can have partial water uptake we can have the enzyme processes begin and then if we don't have enough water for full emergence of that radical then what we have is the seeds dying on us and that's one of the reasons why we recommend a spring or a fall planting unless we have irrigation because we're likely to have a prolonged period of wet weather and be able to maintain soil moisture so after the seed coat cracks the radical comes out then the radical grows down and at some point that radical anchors itself and then it pushes this hook up through the soil surface and drags a cotyledons with it and the seed coat falls off so that pops up above-ground these are the cotyledons that were in that seed coat and this is the growing point the first leaf then is a modified leaf alfalfa's generally a trifoliate leaf plant but the first true leaf up here is a mono foliat leaf and then here again are the cotyledons and here are the new leaflets beginning to grow the reason that this is important is that when we talk about herbicide applications they oftentimes recommend a four to five leaf stage and it is important to recognize that the cotyledons and this mono foliat do not count in that when we talk about four to five leaves we're talking about four to five trifoliate leaves so after a little bit more growth you see the first trifoliate leaf out here again are the cotyledons the mono foliat that we saw whoops and then another set of leaves coming out and then here again is a little later stage and part of the reason I put this here is I usually ask people okay what leaf stage is this and will usually get answers that this is around four or five leaves when we counted leaf stage remember first we do not count this leaf because it's not trifoliate but also when we talk about a leaf stage we are counting leaves where the leaflets have fully expanded so that they're not touching each other so this one would count this one this one this one but not this one since these have not fully developed yet so this is about a three or four leaf stage alfalfa again that's important to understand just from the standpoint of when you can first apply certain herbicides this is a little later then and here you see those cotyledons that we've seen green all the energy has been absorbed from them they then dry up and essentially fall off on the ground and here is the stem going up now one of the things that happens and this is an important process to understand is that those plants begin to grow the root goes down the stem comes up and then at some point that crown pulls back on itself and forms a little Ridge here and this is the crown you can always feel this in a plant by taking your hand and rubbing it from the stem down to the root and at early stages you'll feel a little Ridge somewhat like an o-ring and then it'll eventually develop more significantly like this I often times get asked on false eating is my alfalfa big enough to make it through the winter and that's not really the appropriate question the appropriate question is does the alfalfa have a crown if you can feel a crown then that plant has per any ated and it will make it through the winter if it does not have this crown then that plant is not a perennial and it will not survive the winter usually this crown develops at about that three or four inch height of plant but again the real test is to look for that crown this then is an established plant and really what I'm showing here is you can see the shoots coming off that develop the next series of growth you can see some existing stems up here that have in this case been cut that others are growing up but these are the buds that will provide the next cycle of growth of that alfalfa so this is a good healthy crown with a lot of stems usually what we like to see is that ground level is something around here so the crown is just below the surface of the soil if we have the crown above the surface we're more susceptible to traffic damage and to winter injury now the other thing to kind of keep in mind about growth then is that when L falfa's cut generally speaking we are talking about regrowth from those buds on the crown however if if you cut high enough then alfalfa shoots will develop from those axillary buds this is where an old leaf was you can see this stem has been cut off here is the cut tip of each stem and then new shoots are coming out from axillary buds along that stem so generally we don't see this in alfalfa because frankly we shouldn't be cutting this high but if for any reason we do that is what happens sometimes will sometimes we'll see this in the spring if we have some growth and we've seen a few times where the stand might get up to 10 or 12 inches and the tip freezes and then what happens is is that along the leaf of axillary buds up along the stem up to the point of frost kill we will see new branches come out of that alfalfa wrong button so generally speaking we want alfalfa varieties with good winter hardiness will have less winter kill but the other thing that happens is that will have less winter injury remember with alfalfa that the buds are put down in the fall and then they survive the winter and then those are what come out and green up in the spring if the stand is lacking and winter hardiness then many of those buds die and we see very few shoots come out in the spring like this and then the plant has to start over in the spring putting out new buds so here too this is a winter injured plant this is a good healthy plant I think you can very quickly get an idea of which is going to produce more yield on first cutting and therefore more yield for the year so we want winter hardiness we're generally recommending a winter survival score of two or less and that winter so injure winter survival score is necessary to reduce the potential for winter kill we still have some we did a few years ago but more importantly year in year out we'll give us less winter injury and more yield in the growing season following the winter now when we look at winter survival we did recommend a winter survival score of two and the way that that is done is to plant the varieties in rows each row here is a separate variety we cut very frequently during the year we seed these plants and then we cut on September 20th when we tell everybody not to cut and what we're trying to do is stress these plants by having them spaced planted by having them cut frequently and cut it a bad time we are putting stress on those plants and so what I think you can see is some rows like this one came out very healthy with lots of shoots and some rolls like this one had lots of dead plants very few shoots coming out so this plant has less winter survival ability than this roll or this roll or this roll so that is a standard test that is run I encourage people when they're selecting alfalfa varieties to select an alfalfa variety with a winter survival score of two or less so we want very winter hardy winter hardy or moderately winter hardy alfalfa varieties again a winter survival score of two or less the other thing is is to evaluate the stands in the spring if you see an uneven Greenup frequently that then means that a lot of the buds are dying over winter that you've got a few that came up when you see two or three stems per plant they made it through the winter the other 15 or 20 didn't and so then that plant has to start over and that will show reduced yield we additionally want more winter hardy varieties if we're cutting at less than 35 day intervals which most of us are for dairy quality hay and also if we're going to take a late fall cutting we generally will give us more yield at this point but it is putting stress on the plant and so we would like a little bit more winter hardiness if we're going to take late fall cuttings the other thing I do want to point out is that with regard to seating it really is a good idea to calibrate your cedar and too many people just throw the bags of seed in the cedar whether it's a brilliant or a drill and then take off it should be recognized that every lot of seed will seed at a different rate because we have variations in seed size we have variations in density so here's an example of a little trial that was done where we took six varieties of alfalfa we put them through a brilliant cedar all without adjusting the rate other words the same setting was left on the cedar and what you see is that these variety is seeded from about 21 pounds per acre down to 15 pounds per acre so here's an example well actually down to 14 we did the same thing in a John Deere drill where we left the setting the same we put those same six varieties through and what you see is that most of the varieties seated at about 16 pounds per acre but a couple were seating up around 20 or 21 pounds per acre so what I generally recommend we're probably not going to take the time to calibrate our drills but our recommended seeding rate is about 12 pounds per acre I would suggest that you look at using that 12 pound rate put a third of a bag in the drill and see if you see it about an acre or put a whole bag in and see if you see close to 3 acres by doing a test with one bag you can get a pretty good idea of how that lot of seed is going to seed and then to recognize that if you buy two different varieties you need to repeat the process for each because the seeding rate is going to be slightly different for the two different varieties of seed the other thing that I will say is that our recommended seeding rate is 12 pounds per acre we usually figure something around six seeds per square foot per pound of seed so six seeds per square foot times twelve pounds is 72 seeds per square foot what you see in this trial here is a study that we did where we seeded at four different rates from nine pounds up to 18 and yes we had a few more come up up to 90 seedlings per square foot as compared to 40 seedlings per square foot but no matter how much we seeded all of the stands thinned down to about 32 plants per square foot by the fall of the seeding year so when you see it at a higher rate yes you have more plants come up but you will also have more die out in that seeding year and you will end up with about the same stand and we had about the same population over the life of this study so a higher seeding rate doesn't really help us in any way it does increase your cost and the other thing that I would be concerned about since all the seeds in the variety don't have the same disease and insect resistance you could in this establishment period here lose plants that had resistance that you might need later on in the life of that stand so we would recommend a 12 pound per acre seeding rate and many people seed more than that but all it's going to happen is those extra plants will come up and then die out by the end of the seeding year if you need further information on this or any of the other things that we discussed you can go to a number of our websites you can use our variety trial update for looking at characteristics of varieties of grasses and alfalfa and for availability we would consider in all cases that we should select premium varieties for improved disease and insect resistance to provide the highest yield for you on your farm