Field Crops Webinar Series - Soil Fertility for Forage Production
March 20, 2017
MSU Extension Field Crops Webinar Series 2017 Session 6, 3/20/17 Title: Soil Fertility for Forage Production, Presenter: Dr. Kim Cassida
And evening everyone my name is Jim sleb I'm an extension educator housed in unison Michigan and I'm your host for tonight's. Episode feel crops webmin our series we're on board tonight with me is James T. Decker jeans is the lead organizer for the series and this is the. Six in a seven part series our speaker tonight is Dr Kim CASSIDY On the subject of salt fertility for four H. reduction. Dr Cassaday is the M.S. You extension for IT specialist housed in East Lansing works all over the state with forged producers and in the industry the forge industry. OK Good evening everybody. I am going to be talking to you tonight as Jim said about managing yourself fertility for forage production so I hope I hope will be at all sorry I'll be able to learn something. And can please do it if you see a question that you think I should answer and I'm not noticing it flagged me down OK So because my little chat box isn't popping up right here at the moment. OK I want to start out just by talking a little bit about how soil nutrients move around on a hay field or pasture to begin with so we can get a little context for how we how our soil fertility fits into this picture. There's a number of ways that we can lose nutrients from our fields and of course the number one way is through our artistic forage whether we're harvesting that is hay or hail ignore or actually grazing it with animals we can also have movements of soil particles directly off the field either through surface erosion or through sole pores or tiles we can lose new. That dissolve in rain water and run off the field and surface runoff we have leeching which moves downward through the soil profile. We have volatile ization which is a loss to the atmosphere when our solar nutrients are converted to a gas and we have the nitrogen cation which is another way that our our soil nutrients specifically nitrogen can be converted into a gas and last from our field. We also have ways we can gain nutrients the primary way most of our nutrients arrived in the field in the first place that we think about used to weathering out of our parent rock material native to our area we also gain nutrients in rain we'll be learning a little bit about that as we go through the various nutrients. All that material that eroded off over here had to end up somewhere so we can have erosion deposits with the wind or the water deposits the the soul somewhere else and now we have a new source of nutrients in the new area we have animal urine and dry and as a source fertiliser of course that will be talking about quite a bit we also have other types of saw amendments which might include things like compost bio char biosolids manure which is technically not the same thing as urine and done deposited directly by the animal manures often mixed with bedding or sand or other things as well and wood ash and other sorts of. Materials we can have mineralisation of the organic matter that is present in the soil from decaying plant and animal matter and we have biological nitrogen fixation so I may be presenting a little bit of an unconventional viewpoint on Saul fertility here because in a forge system to me you have to consider all of these things and how you can control them in order to. You better manage your resources. It's also important to understand our basic nutrient response curve. This is a pretty standard idea regardless of what type of crop that you're growing. And hey if you look here for any generic nutrient along the X. axis on the bottom here we have increasing levels of that nutrient in the soil from. No Zero to non to very high levels and over here we have the applied nutrient rate. In over here we have and that are the applied nutrient rate corresponds to this black line and over on the right here we have the percent yield and that's expressed as a percent of the maximum possible yield and that relates to this dotted green line so that you can see that as we increase the amount of nutrient in the soil we get an increasing response of yield from whatever the crop is in till we reach a certain level where it's going to level off because at that point the plant has all that it needs and adding more is not going to drive any more yield. And we typically defied the critical level here as ninety five percent of that maximum meal. So when we are before when the sole test is before that ninety five percent maximum yield for the crop we call that the response zone so in that point we're going to get. A response by the plant to our addition of nutrients. This is also sometimes called the build up range because if you. Can afford to if you actually apply more nutrient than the plant can use in this range you can start to build up a buffer. Nutrient in your soil. Once you're over that critical level there's really. We call this the maintenance range and it's an adequate zone for our plant nutrition. And then for most a chance we also define what we call a draw down range where we're well above the maintenance or well above that critical level and at that point was some nutrients we may actually be. Having too much that will cause some environmental problems we will talk about that as we go along so sometimes when you're in that zone it's actually beneficial to not apply any more nutrient to the field and actually try and draw it down by removing more nutrients in the crop than what is. Then what is out there. OK I wanted to present some numbers here I know this looks like a big table and numbers were going to come back to it in a couple of places. But this is just to give you an idea of the annual nutrient remove all that we have in hang a crops and in corn silent crops. So what you're looking at here the first column of numbers for phosphate and pot ash is the amount of that nutrient per ton of dry matter of these crops that are listed over here so in other words for corn solids in one ton of dry matter there is thirty four pounds of nitrogen twelve pounds of phosphate and twenty nine pounds of potash. And then I'm converting that to a total amount of nutrient pulled per year per acre by taking that per ton number in multiplying it by a typical yield and most of these were just taken from our M.S. You variety test numbers as is realistic yields here from Michigan. I don't know why my little cursor keeps disappearing on me. Anyway so what you end up with here is the total amount removed. A year for and this is ranked in order by the amount of nitrogen. From the most nitrogen to least nitrogen it's because I wanted to rank it by something. So you can see that corn solid is actually removing the most nitrogen. But not the most potash because some of our other crops have a higher concentration of potash in them and therefore even though the yield is lower they may be pulling more out of the soil so my point that I want to make here is if you look at these us a pretty big numbers. That you are draining from your soil every year when you take off your crop. Now in the case of the ones in blue these are all humans and so they can make their own nitrogen. Which is good if you don't have to worry about those numbers but you do have to worry about these ones and they are pulling a significant amount of P.M.K. out of your soil. And before we get into the nutrients themselves I just have to make a plug for small testing because when I have someone call me. On the phone and they want to ask me a question about their fertility on their forage field the first question I always have to ask them is do you have a salt test and what were the numbers because if you don't know what you're starting with you really don't have any way to make a reasonable guess about what you should do so this is always your for your first step is to get that soil test so that you know what your what your baseline is and I just looked up numbers here for the basics all tests cost at the M.S. You saw a plant nutrient lab is currently eleven dollars for a basic sole test which includes ph P.K. magnesium calcium and C.E.C. and it comes with recommendations for what you should apply unfortunate from their lab if you want to soil organic. Under test that's going to cost you five dollars more. And of course there are other labs other than ours where you can get similar testing done for sometimes less money I hate to say. But it doesn't matter where you get it as long as you get it. Now it's important that she. Get a separate small sample for land units that are similar and we're going to I'm going to show you how to do that in the next slide Typically I recommend to test grasslands at least every three years. Maybe every two years if you're really trying to do some fast improvements. One of the current changes to our recommendations here in Michigan for grasslands is that typically in the past we have told people to salt test to a six inch depth. Regardless of what kind of crop it is but the current recommendations for pasture and hay field is that if that area has not been cultivated recently in other words it's been established for a while you should really only sample to a three inch depth because in a perennial pasture most of the time where surface supplying all of our nutrients after the established phase and that tends to concentrate them in the opera saw levels and that's where most of the roots of the plants will also be and so it doesn't really help you to get that deep or soil profile but if it's been recently cultivated you can go ahead and go to the six. And you can use these results to help guide your correction of your most limiting nutrient first so and in other words if you perhaps are limited in money. Look and see what the soul test tells you about what is the worst thing that you have going and fix that first beef and don't try to fix everything at one. OK so here's a little bit of information about how to set up the sampling scheme in a field where you have a field maybe that is not very homogeneous across the whole field it's got a lot of different things going on. So maybe this is all harvested as hay at the same time. But you have this wooded area and there's an area of mock his there's where your line pile was once upon a time and there might be some difference all types of here so split this into three areas typically an area shouldn't be any bigger than twenty acres. You know order to be able to get good distribution of your samples and then go out there and get samples at least twenty from each area in this zigzag pattern so you can see if you look at all of the different spots here it kind of evenly covers the whole area of the field and then you would do that over here the same way of avoiding the spot where the line pile was because that's not going to give you good numbers and over here the same thing so you end up with three samples for this field. And then you will composite those twenty cores per field into one bucket mix them up put them in a bag set off to the lab. These this way to do testing is to get a soil probe these costs are seventy five to one hundred dollars and a lot of people have told me it's probably about the best seventy five two hundred dollars they ever spent because it really does make getting small samples a whole lot easier but if you don't have a soul probe you can still do it with a shovel or a trial. Just digging a little trench like this and then taking a half inch thick slice on a diagonal off the wall of that trench and that is what you would then get twenty of those slices from different spots and mix that your buckets and it off. And this will be a lot more work and it's a lot harder on your back. All right. Soil ph is the first thing I'm going to talk about because to me this is absolutely the number one sole fertility consideration you need to have for for ages. Because if this is not correct. Your nutrients are not going to be used correctly by the plant so basically I tell people if you're buying fertilizer without first cracking your soul ph you're wasting your for lives or money because if the plant can't use it. What what's the point of buying it and here's just an example of what that would look like with alfalfa where we have increasing ph cross the bottom of this chart and then dry matter alfalfa yield in pounds per acre over here and you can see that as the PH is increasing we are getting more yield from our alfalfa with everything else being the same intil you get up for Alfalfa are out of ph of six point eight or so and at that point is where it levels off. So if you want to get the best bang for your buck you need to be in this ph range. Why is that so important it is important because of this whole chart right here at low ph plants can't access their essential soil nutrients. This box is showing the optimal range of PH for forage crops so basically between five and a half to seven is the range you want to be in and what you see here for each one of these nutrients the with the this bar indicates how available the nutrient is at that PH So the wider the bar is the better and you can see that at low ph a lot of these essential nutrients are not very available and you get up into this range your bar is wide and your plants can take up the nutrient. Another thing that happens. Is it that low ph soil aluminum and manganese actually can become toxic to some of our Lithium specific or some of our for just specific leetle humans. Particularly alfalfa So again keeping the PH towards seven in the high end of this range for those crops is better. When the PH Saul ph is too low it reduces the soil biological activity of the microbes so that they are less able to mineralize nutrients and make them available for plants it also reduces rise O.B.O. nitrogen fixation. We also know that low ph Saul's lack good structure and tilt which is another factor in your nutrient availability. And it's been shown that in no till systems low ph at the sole surface sometimes reduces the effectiveness of our No two herbicides. So for pretty well forage crops the PH of range that we would like to see differs a little bit depending on what kind of forage it is the grasses can take the lower end of this range so they can be down around five point five to five point eight before you need to really think about changing your PH clovers and tree falls or medium they need to have it no lower than six and a half and alfalfa we really want to be up there in that six point eight. So it's also important when you send in your soul test to be accurate in telling the lab what crop you're going to be planting are growing so that they can give you the right recommendations for the plants you have. In your field. So how does the soil ph get too low in the first place it's not always anything that we did. In fact here in Michigan and the biggest thing that contributes to that is our native soul condition because whether glacial soils tend to be low in Ph. Just the nature of them. Due to natural leeching of elements out of the soil over you know thousands of years due to the fact that we are in a fairly high rainfall area compared to some other parts of the world. However we also know that application of acidic synthetic fertilizers will help build a city in our soil this chart down here is. Just showing the amount of lime equivalent that's required to neutralize is City in one pound of nitrogen from different nitrogen sources. So ammonium nitrate produces enough acidity. That it would take one point eight pounds to neutralize that ammonium sulfates our most acidic nitrogen source which takes five point two pounds a lime to neutralize it so just something to think about how do you know you may get the Ph corrected at one time but it's going to. It's going to continue to citified over time and go back in the direction that it started from another thing that contributes to Los all ph is destruction of solar get it matter through tillage or some of our other crop practices and the reason for that is that soil organic matter has actually a fairly large amount of buffering capacity and helps by itself neutralize some of the acidity in the soil and lastly a factor that is affected by our management is erosion of topsoil because typically the subsoil is more acid than the topsoil is and if the top soil erodes away and leaves you with you know an inch or two of topsoil or no topsoil on top of that acid subsoil then you're going to have a more acid situation then if you had been able to hold on to. That topsoil. So how do we fix this one way is to increase the amount of soil against matter in our soil this is a very slow process however and you can't really rely on to say I need to fix it right now and get it better so that my alfalfa will grow but the good news there is that growing pressure for ages in and of themselves is a very good way to increase oil again it matter. It's just slow. I see there is a question there about nitrogen fixation by legumes and does that lower the soul ph in the answer to that is no in fact the rise O.B.O. require a pretty high PH So they would if they were going to lower the if they were to lower the PH They would actually put themselves out of business. So our second way that we can try and increase our Ph It's faster but still slow is to apply line. And this is still going to take six to twelve months to correct the PH using lines so this is not a quick fix it requires some forward planning. To get things set up. So that the soil is got the right ph when you need it to have it. It takes more line to change that ph in a heavy soil than it does in a sandy soil. One thing we have learned here in Michigan is that if you're trying to grow forages on a mock soil. Really don't benefit from lining. Because of the higher getting matter that they already have. Let's see live typically needs to be reapplied every two or three years as it leaches out in is. And as you apply nitrogen the best timing for putting it out there is to apply it to the grasslands in the fall so that that soil reaction. Can be proceeding during the dormant season in the winter when your plants are not growing so that everything is ready to go there in the spring and also avoids you having to drive on the soil with a heavy live truck in the spring when everything is wet. For forages typically recommend not to apply lime at more than two tons per acre in one application if you need to apply more than that you just need to do multiple applications a do it phase it in. Jim we've got a question in the check box we do yes does some of PH affect the rate of leeching of nutrients. To soil ph affect the rate of leeching Well that's kind of a good question I'm not sure I know the answer to that my initial my initial answer is no leeching is more a factor of. Four The things that leech mostly are not going to be strongly attached in small particles and so it's more a function of how much water is moving through the soil. Things that are strongly bound on to the soil aren't affected that much by water. Or Ph So I'm so much. OK now I've lost my picture here we go. All right our lining materials differ in their neutralizing value based on both their chemical purity and their processing this chart and actually the charts I just gave are taken from this bulletin line from Michigan soils which you can find online at the end of this talk I have a list of the sites where that those could be located. But this is just showing different liming sources and their neutralizing value based on pure calcium carbonate as the base. This figure is showing the the factor that the finer the grind size of limestone the quicker the PH will change basically if you grind up limestone rock. Into big boulders and throw it out on a field you're really not going to get very fast change of your ph because the surface area is not large enough and big rocks just don't. Do much for your for your Ph You want to have it finally ground you don't want to have very many particles or a larger than what we call an eight mesh size and that's roughly equivalent to an eighth of an inch so you want to see Actually most of your particles should be in here in the fifty to one hundred mesh size which is very fine growing. Also there's two systems used to describe the effectiveness of limestone one is called the E.C.C. system effect of calcium carbonate which is a calculation based on the fineness of the grind times this neutralizing value if you go to this were bullets and it will actually give you the fine details of how to calculate that but this is the most useful way to assess the effectiveness of most materials. But you also sometimes see calcium carbonate equivalent used. And this is used mostly for things like the sugar beet or water treatment lime or morrow because those are those are hard to convert into the other system. I get questions about pelletized live people have the perception that it works faster than regular lives all pelletised line is is finally ground lie processed into pallets that are easy to spread in any kind of offer lies or spreader but research shows that doesn't actually change the sole ph any faster than other sources of equivalent E.C.C. that are applied at the same rate and it is significantly more expensive I just looked up some prices today. I'm not sure actually this is an older bulletin so I'm not sure what the price of. EGG line is today but pelletised live is right on one hundred sixty five to six hundred dollars a tonne and I'm pretty sure that's more expensive than one. So probably not worth it. I also get questions about gypsum people want to use that as a lining material gypsum is got some good features it's an excellent nutrient source for calcium and sulfur. But it has no significant acidity neutralizing ability. It gets that reputation because it does have some chemical features by which it helps to neutralize aluminum toxicity and subsoil which is as I said before is beneficial for lithium for ages but in this case it's not really related to Ph. In a calcium situation the calcium in gypsum is more saw your ball and will reach the subsoil faster than the calcium in line but most of the time calcium is not limited in our mission soil so we don't have to worry about that. Also gypsum can improve structure of salient soils which increases moisture retention and drought tolerance but again sailing soils are rare in Michigan. So primarily what people in Michigan are using gypsum for is a sulfur source. All right now we're going to walk through our major nutrients. Just did brief nitrogen is very important in the play and it's a component of protein enzymes the D.N.A.. Plant can't live without it as I've said before nitrogen fertilizer is going to acidify soil and increase the need for lining. You don't see available nitrogen available on a standard soil test because nitrogen in the soil at any moment in time is a function of mineralisation is constantly being added and lost and so by the time you would get the results back from your sole task your number in. Your soil would now be different. And so therefore it's not usually reported author told us we just have recommendations for how much nitrogen to apply to our various crops the three mechanisms that it's lost by include volatile cation leaching. And we have our natural gain mechanism which is our biological nitrogen fixation which occurs in these little. Nodules on the roots of our league games where our result real bacteria live. And pulled nitrogen out of the air and make it available to our plants and this is a very good source of excellent more or less free nitrogen. In fact I recommend. That. Rise O.B.L. nitrogen should be the primary end source and forage systems. Like gives have a lot of beneficial. Characteristics for animal nutrition as well. We like to aim for having at least twenty to sixty percent lead you on a dry matter basis in a mixture of for ages. Typically one hundred percent the game is not used in past years but is perfectly acceptable for hey the reason we don't like it in pastures is because it increases our risk of pasture below. But over all our advantages of the early years are low cost renewable source of up to two hundred fifty pounds of nitrogen per acre per year this is inherently slow release nitrogen because it's organic. And that Legume tissue needs to break down and be mineralized by the soil microbes to before it becomes available to plants. And so it's you know just be gradually metered out over time and you get a more and more consistent supply to your forage than. We can over seedling gives it to existing stands without have. To use tillage. They're also a rich source of a variety of different bioactive compounds that assist with protein degradation in the silo or in the room and of the animal help with parasite control and have some health benefits for immune stimulation and other factors which is a whole nother talk to go into. On the down side like humans. If they are being grown in a mixture they can have challenges with chemical we control because we don't have herbicides that will take a grass out of the lagoon or a lick you mout of the grass. It's also with a mixture it's difficult to maintain a constant percentage of the game in every cutting which can make rational balancing very challenging for dairy cattle. And there's a perception that that when you have a natural system based on the games that you're not going to be having any leaching of nitrogen into groundwater some of the other environmental disadvantages and that's actually. Probably less of a problem with forage systems but in a poorly managed four system you can leak just as much nitrogen as of in a fertiliser based system. So you have to be careful how you do it. Now in a forged crop the timing of application is critical because nitrogen really pushes plant growth unlike any of our other nutrients you can use this to your advantage by using the application timing to compliment your seasonal forage budget so that you get the growth where you need it to be. Typically after you apply nitrogen you should be ready to use extra forage two to four weeks after that nitrogen was put on. And it with typical application rates here in Michigan we will put on fifty to two. Hundred pounds of nitrogen per year for most of our perennial for ages. And that would give us a growth increment usually of ten to fifty pounds of forage dry matter for every pound of nitrogen that you put on. Now in a pasture situation in particular you want to avoid putting nitrogen on when you already have too much forage because it's going to make you have even more forage in less you are planning to harvest it as hay or hail it or bale it. Typically in a perennial Grassley in situation if we are applying more than one hundred eighty pounds of diet should appear we are likely to have an acceptable leaching going on. And this can be reduced by putting the nitrogen on and split applications where you only put on about fifty pounds at a time or just split split things. Split things out so that you are putting out less than fifty pounds at a time. We also have slow release nitrogen fertilisers the E.S.N. which theoretically reduce losses and can even out the nitrogen supply but most of the research has shown the cost effectiveness of these on grasslands is somewhat questionable they don't always see to pay for themselves with enough extra yield to cover the cost of the fact that the fertiliser costs more in a forge system. What we recommend people not to do is don't apply large amounts of nitrogen in the fall because it delays cold hardening of the plant it can reduce which are survival but it can be beneficial to put on a very small amount just to help the plant. Get ready for winter. We don't want to apply nitrogen to pastures or mix stands of PE fields they have more than thirty percent lead given them because Libyans are big. Sickly lazy and if you give them synthetic nitrogen they will stop fixing their own and just use what you're giving them which kind of defeats the part of the purpose of having them out there in the first place. We also recommend not to apply nitrogen to forage is during drought partly because that's a bit of a waste of money because it requires water in order to get that nitrogen into the soil where the plants can use it and also because if it does manage to get into the into the soul of the plants are not using it you're very likely to end up with nitrate toxicity in the forage which can be fatal to your animals. So wait for the rain to come back before you start putting nitrogen out. Now potassium has to me is the second most important nutrient that we need to consider in a forge system and the reason for that primarily is because this is our more most important nutrient for stressed tolerance in any time that you have a perennial plant you wanted to live for a long time stress tolerance is very important and potassium helps our forage plants with tolerance for cold heat drought diseases and insects. And help keep your stand lasting a long time. If you have a potassium deficiency most of our forage crops are lithiums will get this very typical pattern of little white spots around the ends and edges of the leaflets if you see that that's a pretty good sign that I need to think about my potassium. This could be a problem with this nutrient because it very readily leeches out of the soil profile it will not stick around for a long time after you put it out there. If you can improve the organic matter in your soil this will help increase the C.E.C. of the soil an increase the. Potassium holding capacity and we also get. Potassium is tell it better in heavy soil heavy lower still soil than it is in a saying in. Our little you for ages have a greater K. requirement that our grasses do which is why you're more likely to see the deficiencies on. We very rarely actually see a big direct response it's not something where you're going to go and apply some potassium and immediately CEA boost in your forge production where you see it is an increase in the lifetime stand productivity because it's improve your persistence. And we do recommend that you not apply more than three hundred pounds of potash at one time just because. The soil can't utilize that much if you put out more than that at one time it's likely to just leach away before the plants can use it we don't really have any environmental concerns regarding application of too much potassium other than it cost you a lot of money. We do have some other concerns this is actually the most common deficiency that I see when somebody sends me a small test and we're troubleshooting fields that have disease persistence or establishment issues. Quite often the potassium is just not there so why is that two factors are going into that we think one is that the tasks are potash got really expensive there for a few years it's calmed down a little bit but it hasn't come back down to where it was before you know any time fertilizer gets more expensive people think twice about putting it out there and secondly we're getting some increased awareness of the fact that too much potassium can be associated with some health problems in our animals One is that we have pastored animals a situation called grass which is more likely oughta. Excuse me on a high potassium soil and probably more important since we have such a large number of dairy farms here in Michigan is that we now know. No the high potassium in forage predisposes dried dairy cows to milk fever and this is a major. Major health problem in you know dairy herd producers are very aware of it and are looking for low potassium forage and we know that we can decrease the amount of potassium that's actually in the harvested for ages by starting the plant a little bit. Because the more the plant has the more it will take up but the bottom line on this is that if you're trying to keep a perennial stand going it really isn't cost effective to starve the forage day and trying to get low potassium forage for your dry cows so what my recommendation is for people is to fertilize the forage for the lactating cows where the potassium is not an issue and find something else. To feed dry couse. That is has the low potassium that you need like for example our dairy farm here on campus. Uses a lot of local forage but they actually import their hay for their dry cows from the Midwest from an area where they cannot. Where they can get some material that's quite low in potassium and for them that's a lot more cost effective that trying to grow that sort of material themselves. This is a trial that was hopes Laurie done recently at Purdue University. Where they were trying to re-evaluate some of our. Fertilizer recommendations for P. and K. in Alfalfa and just a couple interesting points here. Is that if you look at Applied potash across this side of the chart and here's applied phosphate over here what they found if they applied no potassium and a lot of potash there alfalfa did not do very well if they applied Nope no phosphate and a lot of potash there alfalfa did not do. Very well where they got good productivity was when they had moderate to high rates of both potash and phosphate at the same time. And this has not yet been incorporated into our soul testing recommendations here in the state the something that we've been having some discussions about how to update our numbers. So that we can get a little bit better information out to you guys. Other labs may already be using this. Our next nutrient is phosphorus check my time here I knew it was going to take me longer than forty minutes we're getting closer to the. Phosphorus is very important energy metabolism of the plant hits are also important route sealing development. Typically we would want to see small available phosphorus of twenty to thirty parts remailing in our twenty to sixty pounds per acre is adequate for most of our for ages and this is another one where we don't really see a lot of yield response to just extra phosphorus directly. A couple unique things about phosphorous is that phosphorus uptake requires in most plants that they have an association with fungi that actually lives on the root and this is called Mike arise a when those are not present it severely. Hurts the ability of the plant to get phosphorus even if the phosphorus is there in the soil. Are phosphorus deficient plants often take on this purplish color that you see here in this corn plant. And another factor is the poor drainage will reduce phosphorus uptake and can cause deficiency even if the sole phosphorus is adequate partly because the wet soil is going to kill our Mike arising so. The moral of that story is that you know wet soil if you have a phosphorus deficiency applying more phosphorus is not going to solve your problem what you need to do is solve the poor drainage problem and then the phosphorus will correct itself. And I'm sure you're all aware of this not to beat a dead horse but the reason we worry about excess phosphorous in our fields is because phosphorous binds strongly to sole particles but can move off the field as both particulates and dissolve phosphorous. Through Macra pores through channels tiles and surface runoff and this causes you trophic ation of surface water which causes things like algebra blooms in Lake Erie which causes public drinking water supplies to be shut down and then agriculture is really in the news and spotlight and not in a good way so. We think about our our phosphorous problems are mostly related to manure management. Would manure is applied to our forage fields we want to not be spreading it just to get manure out of our confinement areas we want to actually budget it to meet the phosphorous removal requirements of our forage crop so that phosphorous is not accumulating the problem with this is that there is a lot more phosphorous and manure than there is nitrogen. And if we're applying the newer to meet the crop phosphorus requirements we're probably not going to be putting out enough nitrogen we may need to actually put out some supplemental nitrogen fertilizer for our non like you. For ages. And here's back to that nutrient removal slide that I promised at the beginning this is just to emphasize look out. Little phosphate actually being removed by a forage crops in comparison to nitrogen and potash really if you're if you have an overload it's going to take you a long long time to draw that down. In any sort of reasonable way. So all fur is a nutrient that is getting increasing attention the reason for this is that its historic place don't need a lot of sulfur historically we got a lot of sulphur to actually arrived in rain you have all probably heard of acid rain. Pollution as a result of industrialization and this chart right here from one nine hundred ninety shows how much sulfur we were getting just rain up to about twenty four pounds per acre per year in these ready areas which was more than enough to keep our forward is happy but then we cleaned up our emissions and now we are getting a whole lot less sulfur through rain. And actually started to see some deficiencies in some areas another place that we used to get sulfur that we no longer do was it used to be present in a lot of fertilizers basically as a contaminant and as fertilizers have been improved we don't tend to see that anymore either. Now the problem with sulphur is that it's also controlled by mineralisation of organic matter in the soil the same way as nitrogen is so salt testing is really not very reliable and a lot of things can affect it it's affected by microbial activity organic matter temperature too hot too cold too dry too wet and also it's less available in sand that it isn't heavy soils. Question coming up here. So the question is current solid united and can you split the application to grow the plant for tons and then starve the plant when it sets a year to get lower energy corn solids forevers and dry cows Well that seems reasonable. I don't know that I've ever seen anyone try it. And think about that for a second. I think the difficulty there would be in getting the nitrogen. To be able to control the nitrogen uptake by the corn so I suppose you could try do that by not putting out siders nitrogen in mid summer but you can't really tell the plant to stop taking it up that would be that that would be the challenging part of that. Idea. And I think about that. There we go all right but we've done a little bit of research here in Michigan looking at sulphur in Alfalfa stands a survey that was done in two thousand and fifteen actually showed that more than half of the stance that we surveyed across state were either deficient or low normal implant tissue sulphur. A follow up some follow up work with that did indicated that the following year it was not nearly as bad which I think relates to what I just talked about in terms of that the weather conditions really affect the amount of salt for president the soil you can have the sulfur there but not be available to the plants in one growing season but in the next growing season it would be OK. If you want to test and find out whether your plants at this very moment are deficient in Sulphur the way to do that is by a plant tissue test whereby you collect. The top six inches from forty to fifty plants across your field typically best to do that in the first cut for Alfalfa and send that to a testing lab. Some of the labs want the material fresh and some wanted air dried so check with them on what they want. And look for the critical sulphur lawful levels in that forage leaf tissue it's a lot more accurate than salt testing so for Alfalfa here sure critical levels and for grasses little bit lower. Some of the sulfur sources that we can use here clued ammonium sulphate potassium sulfate gypsum and salt all maggot obviously most of these also provide us of other nutrients at the same time. Not of these effects all acidity you may have heard that sulphur is used to actually acidify soil for the few crops it actually like as its oil but that is elemental sulfur that is used for that and that is not one of the sulfur sources we would typically use for the forage. And if you do find your plants to be deficient you could try applying twenty to thirty pounds of sulfur per acre per year to out. And just at this point we're recommending people that the best thing they could probably try if they think they might have a deficiency is to try a little bit of Sol first for allies ation and see if it helps in their situation. Now we have a couple of. Maria for time. Flying along here. Magnesium is an important nutrient that is sometimes. Deficient on acid sandy soils with a coarse subsoil here in Michigan. The other place that magnesium deficiency can be seen with for ages is when you have really high salt but as you know I don't know how likely that actually is here in Michigan for the reasons I previously talked about. But we should on the soul test your magnesium. Saturation should be greater than your potassium saturation to avoid that problem. I don't think we see a whole lot of magnesium efficiency with forages here in Michigan because a lot of people use dollar Medich lime to correct their soul ph decline has magnesium in it. If you are using Cal CITIC lime you may be more likely to have a problem and the forage crop that seems to be the most susceptible to magnesium problems is corn. If you have a critical deficiency this is one that can be corrected with a Foley or application of only one to two pounds per acre that won't be a long term fix but it might snap your plants out of the out of the droop. Boron is one of our micronutrients it's very important for the Gives and brassicas it is not generally required for grasses and this is one of our not micronutrients it's actually toxic when too much is applied to plants need a little bit but they don't the a lot in fact a lot can kill them. It's also applied very very small amounts of plants only need the ones that need it only need two to four pounds per acre so that's hard to apply usually put either as a solid that's mixed with a bulky or fertilizer are it can be applied as a spray that can either be applied to the foliage or directly to the ground. You don't want to put Boron out rate before planting or in the seat for all because it inhibits germination of seeds. It's also more likely to be seed in Sandy or low organic matter soil like a lot of our other nutrient deficiencies the damage can often look a lot like potato leaf damage. This is Boron deficiency appear with Typically you see stunting in the youngest leaves and they can turn a very light yellow white color. I don't really think it looks much like potato leaf opportunity some people get. Manganese is sometimes deficient on corn corn or alfalfa here in Michigan on high ph poorly drained compacted or highly organic soils this could be really patchy within a field and this is another one that can be toxic particularly in a highly acid soil so you have to be careful putting it out typically will be put out as a foliar fertilizer because it's immobilized in soil if the PH is correct. And it's put out is only one to two pounds of Magnes per acre. Or you can try and reduce your soil ph but I don't recommend that isn't options. Other trace elements are not likely to be needed on for ages here in Michigan but if you suspect that you have some other kind of deficiency going on you can get extension people out there to look at your plants help you figure that out or use plant tissue testing to confirm whether you really need to apply anything because micronutrients are quite expensive. There have been a few cases of alfalfa or sorghum Sudan grass speedy copper on Sandy muck soils at rates of two to four pounds per acre and sometimes was sorghum Sudan grass or corn on neutral to alkaline Mox oils will sometimes respond to zinc at ten pounds. And I promise I'm almost done. I just wanted to say a little bit about Foley or fertilisers because I get a lot of questions about this. The companies that are selling these products are. Very aggressive and they have a lot of products. But unfortunately no independent research actually shows consistent cost effectiveness of these products with forages for cup. A reasons One is that perennial Grassley AIDS are not well designed for Foley or nutrient uptake due to having a waxy cuticle and relatively relatively few pores in the leaves. For the case of our macronutrients nitrogen P.K.I. calcium magnesium and sulfur almost always the soil applied fertilizers are more cost effective than Foley or because plants need so much of these that they simply can't absorb an off through the leaves to make a big difference if the soil is really deficient. Even with the micronutrients that I mentioned earlier that can be applied as Foley or feedings often require multiple applications in order to be able to supply nuts. Another reason that we see a consistency with these products is a you know a lot of people say I use this product and I really could see a difference in my field. But if you read the labels closely or dig into it you'll find that a lot of them contain things that are not nutrients they contain plant growth hormones frequently and these can have a much larger effect on plant response the nutrients do. And often make plants look taller greener when the biomass is really not change so it looks a lot different but your yield hasn't actually proved. Another handicap with these products is that the formulations are proprietary and change all the time so the same product that you use this year. And last year may not actually be the same thing at all that's in it which can cause a lot of you consistently in results. This is just a little summary and this is the last slide to to show a timing summary for. Correcting fertility problems. And I always tell people the best time to correct a big problem is on grasslands is before establishment because you have the opportunity at that time to do to. If you are in that type of a system which will help distribute your nutrients more thoroughly you always want to try and get your soul tested and get your live applied at least six months before you're going to plant to give time for that lime to correct the PH You put the P.K. on at that same time or you can put it on any time before planting. The starter nitrogen should not be put out in til planting time because it will not stick around to the time when the the seedlings come up. And again on a stablished feels to repeat your assault test every two to three years ply your live in the fall as needed every two to three years P.M.K. can go on in the late summer and fall. Or any time basically But that way you get the benefit of the potassium helping you with your winter survival. And nitrogen should be applied to grasses don't need it for early in split applications as needed to drive your growth. And this is what I promised just some sources for some of this information I believe that this. This presentation gets posted online so that you can go back and look at it any time or printed off or. The should be clickable links I hope that would work on that type of scenario and then lastly we have this resource which is our forage Web page here if you go to this web page address down here click on the extension page up here it will take you to all kinds of resources including the things on the previous page with links so that you can access them. And I've done. We have time for any question if anyone has a question they'd like for Kim K. answer she one popped into the chat. Is there one in there because I don't see it yeah the question is for corn has a machine done many test plots for adding small amounts of twenty eight percent when spraying O'Steen merchants. I am not aware of any We probably have not reset our situation with corn here at F.S.U. is that for some years we have not had a faculty member working with cart but the good news there is that we just hired somebody who started last November Dr Manny saying and he will probably be starting to do a lot more of that sort of research. And I could certainly relay that question to him to find out if they're planning anything like that. Any other questions for him before we move along to our. You valuation questions. OK.