our presenter today is anative of milwaukee in wisconsin, and has earned hisbachelor's of science degree from the university of wisconsinat stevens point. he's recently completed auniversity of north dakota postgraduate study program in geographic information science. over the course of jon's career,he's worked as a dairy herdsman in southeasternwisconsin, and an integrated pest management field scoutfor the university of
wisconsin cooperative extensionand mapping soil scientist in east centralillinois. in north dakota, jon has workedas a mapping soil scientist in the east centralpart of that state, as a soil conservationist in sheridan andburleigh counties, and as a district conservationistin griggs, steele and dunn counties. he's been in the area ofagronomy for western north dakota, and currently is thearea resource soil scientist
in that area. he's been actively involved asan advisor, and webmaster for the manitoba - north dakotazero tillage farmers association, the north dakotachapter of the soil and water conservation society, andrecently completed a project called the southwest northdakota soil health demonstration. he's been actively learning andteaching about soil health since 1992.
and, of course, he grows hisgarden without any tillage. and so i'd like to turn thispresentation over to you, jon, and let's all enjoy thisafternoon's presentation. jon. it's my pleasure to be heretoday to cover what i know about cover crops. cover crops have been aroundfor a long time, but more recently, we've been using themfor some new purposes and for some new approaches toimproving soil health.
so that's what i'd like to sharewith you today in my presentation. first, i'd like to cover alittle background information on soil health. then get into the thoughtprocess of developing your own cover-crop mixes. and then a little bitof a case study information at the end. so with that, we'llget rolling here.
i realized when i startedputting this information together that there was no way iwas going to be able to tell everybody exactly what theyshould do for every situation in every part of the country. what i wanted to share withyou today was what i have learned, mostly from producers,on cover crops and how cover crops areused these days. this practice has been aroundfor quite awhile, but more recently, we've been looking athow we use cover crops for
improving soil health anda lot of other purposes. so that's pretty much what iwould like to discuss today. i'd like to start out with somebackground information on soil health, then get into somediscussion on developing cover crops, and then a fewcover crop case studies. and when i started putting thisinformation together, i realized that i can't giveeveryone an answer of what cover crop they should grow forwhat purpose in their part of the world.
so i'm really not going to giveyou a lot of answers, but help you realize what questionsyou're going to need to ask yourself as you gothrough your thought process of deciding if and when, and howand what you're going to use for a cover crop. this image here is just anexample of a cover crop that was broadcast in thestanding corn. but the first thing i thinkeveryone needs to ask themselves is whatis your goal?
don't make the use of acover crop your goal. have a goal in mind of improvingsoil health and having some other purposes withthe use of a cover crop. don't grow a cover crop justbecause that's the in thing to do right now. really think this through anddecide what is your goal? what do you want that covercrop to accomplish? and what we're realizing, isthat cover crops, particularly these mixtures of species, canbe an excellent tool to help
restore and improve soil healthand soil functions. and we'll get into thathere a little bit. so restoring and building soilhealth is a very worthy goal that you can use a cover cropas a tool to help you get down that road. as i was digging in someother information-- i'm kind of a student of thomasjefferson, and came across some information in hisgarden book that he kept, and the fact that he used turnip,buckwheat and vetch as cover
crops at monticelloback in 1794. and how he realized that it wasimportant for him to have some crops, some cover crops,that would build the soil to alternate with his cash crops. so a little bit aboutsoil health. soil health is the continuedcapacity of the soil to function. and i have the words, functionand living highlighted there, because that's really what we'retalking about when we
refer to soil health, is howwell is your soil functioning? and we have to understand thatit's a living system. it's a biological system. and once we change our thinkingto realize that the soil is a biological system,it's a living system, then our approach to soil managementchanges. and we begin to realize thatwhat we're doing here is creating habitat for thesethings that live in the soil and drive all of the processesthat we expect the soil to
perform as an agriculturalsystem. so when we look at cover cropsfrom a soil health perspective, they're reallyfunctioning as a primer of soil biology. they're providing this foodsource and this diversity that the soil food web reallythrives on. so we're finding that if we putthese multi-species cover crops out in our systems, thatthey're really priming the soil and bringing it to a higherlevel of function.
so we need to think aboutfeeding the underground herd as it's been referred to. and if we could round up all ofthese microorganisms in the soil and run them across ascale, like we could cattle, we would have at leasttwo cow's worth. it's probably closer to fivecow's worth, but at least two cow's worth of soil organismsper acre. so if you can imagine two cowsstanding out on every acre of your land needing to be fed,that's really what we need to
understand as we manage ourcropping systems and grow these cover crops. so the soil food web in thisdiagram i borrowed from the soil health primer, or soilbiology primer, and i like this diagram, because it reallyemphasizes what we need to understand, and what weneed to think about, when we're managing these systems. so this system of the soil,as a biological system, is supposed to be poweredby the sun.
and that sun throughphotosynthesis of green growing plants, provides thesugars that exuded out of these plant roots, the residuesfrom these plants, that feed all of the smallestmembers of the soil food web, bacteria and fungiin particular. then as these organisms areconsumed by larger organisms as we move through the foodweb, that's where more nutrients are made availableto the plants. whenever someone gets eaten inthe soil food web, that excess
nitrogen as those carbonnitrogen ratios change, that excess nitrogen is fedback to the plants. so the plants are able to feedthe soil using the sun as a source of energy, and then theorganisms in the soil are able then to feed the plants. and we have these cycles thatare powered by the sun. this is how the soil isdesigned to function. so if we do our best in ourmanagement systems to mimic nature and manage the soil theway it was designed to
function we're finding thatour systems are much more productive, and efficient,and profitable. so this is our toolbox. green growing plants are thetools in our toolbox. we need to think about when wewant to manage the soil. we need to think about managing that soil with plants. so we should be reaching forseeds rather than steel. to do tillage, we should bereaching for seeds to grow the
plant or plants in that soilthat will address whatever it is we need to managethat soil. so when we get right down toit, all of the things that happen in the soil that we relyon from an agricultural perspective, we expect the soilto infiltrate, and store water, and supply nutrientsto the plants. and really, what it's allabout, is this habitat. and in the world of soilorganisms, soil aggregates are their habitat.
and you can see in this littleimage down in the lower right, an aggregate forming, the sandgrains, the silt, the clay, other things being gluedtogether by the glue that's produced by bacteria, fungi,plant roots, earthworms, et cetera, that glue theseaggregates together. and it's important to understandthat we can't create aggregateswith tillage. we can only break theseaggregates down with tillage. it's these glue makers, theseorganisms that live in the
soil and plants, that can buildthe soil aggregates, and create this habitat and thisstructure in the soil, that allow it to perform thefunctions we expect it to perform, and to provide thehabitat for the organisms so they can do the nutrientcycling. an easy way that we use toassess soil health, is just to look at aggregate stability. look at how good are theseglues holding the soil aggregates together.
so if you take a piece of soiloff of the surface of your land, or the top few inches ofyour land, those natural aggregates, those clumps andclods that it breaks into, let them dry out, so they're airdry, and then drop them into some water, you'll get a verygood measure or indication of how well is my soilfunctioning? how good is the glue holding theaggregates together, and how well is this habitatstabilized in the soil. when that water rushes into theaggregate and pushes the
air out, if the glues are ofhigh quality, that aggregate will hold together as inthe image on the left. if that air rushes out as thewater rushes in, and the aggregate explodes anddisintegrates in the water, then that's an indicationthat your soil habitat is not very stable. the quality of your organicglues is not very good holding that soil together. when it rains, the soil getswet at the surface, those
aggregates disintegratewhen they get wet. at the surface, they plug thesystem, and the water has a very difficult time infiltratingthe soil, and you see a lot of water runoff the field. so we really don't have a waterrunoff problem, we have a soil, water infiltrationproblem. and that can only be solved byfeeding soil biology so they can make these glues that willstabilize our soil aggregates. where a lot of this takes placeis in this area right
around the roots of livingplants, which is called the rhizosphere. and this area of concentratedactivity is where all these glues are made, where all thenutrients are cycled, et cetera, which is very convenientto the plant because the nutrients are thenmade available right next to the root where the plantscan absorb them. so in this image here, i justtook a barley plant, an actively growing barley plantthat i dug up, took the soil
off, but a lot of soil was stillclinging to the roots of this plant, because there aresugars being exuded by these plants, all these organisms areliving right in this area where all this easy food isbeing made available. and so we have a lot of sugar,a lot of glues, a lot of activity right there causingthe soil to cling to these roots when we digthese plants up. but it's a nice visual of howall of this is happening in this rhizosphere right nextto the plant root.
so for the keys to the kingdom,so to speak, for managing for soil biology andsoil health, there's really four key things that i look atand explain to folks when they're thinking about how cani manage my soil to improve soil health. and those four things are tominimize soil disturbance as much as possible. there are some situations wherethere's going to be a certain amount of soildisturbance, but look for the
ways that you can minimize thedisturbance of the soil. a lot of producers in my part ofthe world here have gone to no-till, so that they have theabsolute minimum amount of disturbance to thesoil every year. maximize diversity of plants inyour rotation, and this is huge, and this is where covercrops are coming in and having a very significant impact. as we need to get as manydifferent types and species of plants growing in that soil aspossible, because we have a
huge diversity of organismsthat live in the soil that need to be fed. and keeping living roots in thesoil as much as possible, provide those organisms withtheir easiest food source. those sugars that are exudedfrom those plant roots is the easiest food source for themto assimilate and grow. so cover crops come into playthere where we have living roots out in that soil for anextended period of time beyond, or in addition to, whatwe normally have with our
cash crops. the fourth thing is to keep thisall covered with plants and plant residues all of thetime, so that we buffer the soil habitat so it's notexposed to extremes in temperature and moisture. and we provide the food sourcefor part of the soil food web that lives at the soil surfacethat lives in that residue that starts to shred thatresidue apart and get it fed into the soil system.
so if we were going to boilthis down to one point, it would be to create the mostfavorable habitat possible for the soil food web. i got a kick out of this littlediagram that i came across of the two rabbits andtheir carrots, because when we're talking aboutcover crops, it's the part below ground-- for me, it's the part belowground that is the most significant, because that'swhat's feeding
yes, we need to have thetop part of the plant to cover the soil. that's important, but we tendto look at the part of the plant and the production atthe surface, rather than looking at the impact that theplant is having in the soil. ok, so that's kind of the quick,the short course on before we actually get intothe cover crops part, were there any questions? we're not seeing any questionsright now.
for the group, please type thequestions into that notes transcript box. thanks. ok, now to get into a littlebit more of the cover crops thought process, the firstquestion in my mind would be, why even bother growinga cover crop. what am i going to growthis cover crop for? and the first one in my mind, isto feed the soil food web, so that i can build thecapacity of my soil to
function, to perform thefunctions i expect it to perform when i want togrow my cash crops. another purpose might be toprovide some supplemental forage for livestock, providesoil cover at a point in the rotation or a time in ourcropping system, when we might not have a lot of soil cover. provide wildlife food or cover,capture and cycle crop nutrients, and this one can bevery important in places where you may have an excess ofrainfall at certain
times of the year. and the best way to keep thosenutrients from escaping through runoff water orgroundwater, is to get them tied up into some plant tissue,so that they're held there until that plant tissuedecomposes and then becomes available to the next crop. we can use the cover crop tofix some nitrogen, some atmospheric nitrogen byincluding some legumes in our cover crop.
in this part of the world, it'simportant for us to catch some snow in the winter time. that's a significant part ofour annual precipitation. so if we can catch that snowthat adds to our water supply and dry land agriculture,depending on what species you have in your cover crop, andwhat degree they mature, we may be able to supportsome pollinators with our cover crops. and we can create pores throughthe soil, through
compacted layers in the soil, wecan create pores with these cover crop root systems. so this is just a short list outof all the things that i'm sure folks could think of, thatthey might want to have as a reason to growa cover crop. so how do cover cropsimprove soil health? and cover crops, we think backto that diagram, we have the green plant photosynthesisfeeding the soil food web. so the longer we can havesomething green and growing
out there, the more we'resupplying that easy food to and if we have a diversity ofplants in our cover crop mix, we feed that whole diverse foodweb of organisms in the soil that much better. from my observation, if we haveliving roots of a cover crop in the soil for at leasta six-week period, we're seeing significant nutrientcycling to the extent that, the nutrient cycling, thenutrients that are supplied to the next crop, are usually equalto the money that we've
spent on the cover crop. so don't necessarily look at acover crop from the biomass that it produces above, butthink about how many weeks has that plant been green andgrowing, and feeding the soil, and not measure somuch how much production is above ground. we also want to produce thatresidue, that biomass, that will cover the soil, becausethat's an important part of buffering that soil and feedingthe soil food web.
so cover crops can really playa big role in feeding the soil, improving soil health,if we have the diversity of species in there, and we can getat least six weeks or so of growth out of them. so some of the questions we needto ask ourselves as we plan for our purpose, is whenand how are you going to plant this cover crop? is it going to be planted witha drill, or a planter, or broadcast, or flown onwith an aircraft?
what species are yougoing to include? how many different speciesand which ones? how are we going to terminatethis cover crop. here, winter terminates ourcover crops pretty handily for us, but you may look at othermethods and timing of when you would want to terminate a covercrop by rolling it, or grazing it, or spraying it. and then, how much coverage isthis cover crop going to leave on the soil, and when is thatresidue going to be present?
is it going to cover the soilduring the time that we need it to cover the soil? planting, the timing, if we'regoing to look at planting our cover crop before we harvest,or after we harvest our cash crop, and what time ofyear would that be? what is our moistureconditions? are we going to be able to drillthat, or use a planter, or broadcast that seed. think about the planting depthand the seed size.
most seeds don't really need tobe planted any more than, any deeper than twicetheir diameter. but when you're planting thesecover crop mixtures, we have large seeds like peas or beans,and small seeds like canola and radish turnip. we found that if we plant thingsabout an inch deep, it's kind of a "goldilocks" zonewhere everything can grow from there. we can mix a lot of theseseeds prior to planting.
they can be purchased all mixedtogether and dumped in the drill or plantermixed together. or we can put them into adrill and mix them once they're in the seed box ifwe're only doing a small amount at a time. if legumes are going to beincluded in your cover crop mix, you need to be aware ofwhich inoculant you need for each particular legume, whetherit's rhizobium or bradyrhizobium, or whatever thecase might be, so that you
make sure that you get the rightbacteria growing with that legume and get thosebenefits of fixing nitrogen from the atmosphere. you may want to do a pre-plantherbicide burndown before you plant your cover crop, dependingon what your time of year is, or yourweed pressure. that's not always necessary, butin some cases, producers are going to want to do that tomake sure their cover crop is the crop that gets theadvantage, rather than some
weeds that might be coming. and then to decide whether ornot you're going to include any fertilizer when youplant that cover crop. in most cases, fertilizer isn'tnecessary, but there may be reasons that you would wantto put some fertilizer out there for the cover crop totake up and hold for you. or if you're at a very degradedsituation, you might need something likethat to help your cover crop get started.
when we're looking at speciescomposition, what we found so far, and what we've realizedfrom looking at some of the literature, is the more speciesthe better is the short answer. but we found that if we haveat least five species in a mix, we seem to have less weedpressure, fewer weeds showing up in our cover crops, andthose cover crops seem to produce more, grow betteroverall, the greater diversity of species that wehave in there.
we also like to see at leastthree functional groups. so we think about warm seasongrasses, cool season grasses, cool season broadleafs, warmseason broadleafs, and legumes as basic functional groups. and we'll get into that herea little bit more. the season of growth, if you'replanting a cover crop, and it's going to do themajority of its growing during the hottest part of the year,then you may want to lean more towards warm season species.
or make sure you have warmseason species in your mix, so that they will grow during thatwarm period of the year. what you're moisture conditionsare going to be, grow some things that cantolerate maybe a little bit drier conditions if it's inthe summertime or wetter conditions if it'sin the spring. temperature, there are somespecies that cannot tolerate much frost, that will die whenyou get a light frost. and there's other things liketurnips that it needs to get
pretty cold, down to 10 or12 degrees before it will actually kill them. so we can manage how our covercrop is going to perform by thinking about what are allthese conditions going to be like during the timethis cover crop is going to be growing. and we can decide if we're goingto use some annuals, or biennials, or perennials in ourmix depending on what our goal might be, and how longwe want all these
things to grow out there. cost and availabilityis also an issue. the availability of a lotof these things is becoming a lot easier. they're a lot easier to findthan they used to be. but we do like to keep thecost down, so that we can achieve our goal withoutspending any more money than we really have to. we need to pay a little bitof attention to the
carbon-nitrogen ratiosof the mixtures that we'll have out there. and at what stages they will beterminated, so that we can figure out how much and how fastthese things are going to decompose, or how fast theymight decompose the existing residue that's alreadyout there. and the last thing that we'vekind of found out the hard way, was herbicide carryover,paying attention to what herbicides have beenused on that field.
and if there's going to be acarryover that might take out broadleaf species thatwe might have in our cover crop mix. so pay attention to that, sothat whatever we plant out there will grow. just a couple of little graphshere that, from some work by dr. tillman, on speciesdiversity. and what they found if you lookat the graph in the upper left there, we look at speciesdiversity when you have at
least five to 10 species in aplant community or in a cover crop mixture, that's kind ofthe peak of the curve of biomass production. so we kind of found that outwith our own observations, and then we found this research thatsupports it, but that's where these numbers come from. we're trying to hit that sweetspot in the curve there to get the most production out of thesethings, and that's why we suggest using at leastfive or more species.
and if you look at the graph inthe lower left, there you can see that the curve startsto flatten out when we have three functional groups-- the cool and warm seasonplants, the grass, the broadleaf type plants, legumes,are some of the basic functional groups. and we'll get into that in alittle bit more detail at the end here when we get into thecover crop calculator. so when it comes time toterminate these cover crops,
like i said, here, north dakota,we can usually rely on winter to do that job forus except for a few winter hardy species. it may be dry enough that itwill terminate the cover crop. i know in some of the irrigatedcountry and in idaho, they can just quitwatering it, and it'll dry up enough that the covercrop will be terminated by drying up. we can graze these covercrops to terminate it.
the caution there is to notallow the livestock to consume all of the cover crop, so thatwe don't have a cover on the soil, we're not feedingthe soil food web. so we need to be aware that,and ideally, only let those grazing animals take less thanhalf of what's produced, and leave the other half or 60% orso on the soil to feed and cover the herd that livesbelow the soil. there's some nice rollers thathave been developed recently with the chevron pattern.
i've seen folks use old cultipackers and things like that as rollers to roll some of thesecover crops down just as they are flowering or justbefore they flower. and a lot of times that willkill most of them just rolling them and breaking the stems. we can also use herbicides toterminate these cover crops when necessary, whether we'reconcerned about moisture use or just timing of our next cropor crop insurance issues. we can go out and terminatethose cover crops that way.
or just let them grow tomaturity if they're mostly annuals, and they'll senesceand die on their own. so the other portion that weneed to look at is, how much cover are we going to have onthe soil when this cover crop is growing? how much growth are we going toget before it gets too dry or too cold, et cetera? how much cover are we going tohave after that cover crop is terminated?
and how much of that residue isgoing to survive over the winter or over somefallow period? and how is that going tofeed the soil food web? and like i mentioned, we need tobe careful of having enough residue after grazing thatwe don't leave bare soil. just a little bit more aboutcarbon-nitrogen ratios. the higher the carbon-nitrogenratio, the slower the rate of decomposition. the lower the carbon-nitrogenratio, the faster the rate of
and you can see that thecarbon-nitrogen ratio for a particular species likerye, will depend on how mature it is. so rye straw, mature rye, has amuch higher carbon-nitrogen ratio than rye when it's stillin the vegetative state. so you need to think about howmature are these species of plants going to get whenthey're going to be terminated, and thatwill determine your carbon-nitrogen ratio.
if that carbon-nitrogen ratio isat or below 30 or so, odds are most of it is going todecompose fairly rapidly, and you may not have a lotof soil cover. so the high carbon cover cropscan cover the soil, increase organic matter, capture andrecycle nutrients, and moderate soil temperatures. our lower carbon cover crops,such as legumes, or some of the brassicas or the grassesin their early stages of development, can fix thenitrogen, are very efficient
at using nutrients and will helpus break down high carbon old crop residues if that'spart of our goal. we can throw these into acombination and get lots of different benefits buildingthat soil structure, increasing aggregatestability, but most importantly, increasingbiodiversity out there, which reduces our weed, insect, anddisease pressures and really helps feed that soil food web. so we need to plan for thatdiversity and look at
including species in our covercrop that are already in our crop rotation. so if we already have a croprotation with a lot of cool season grasses in it, it'sprobably a good idea to include warm season grasses,cool season broadleaf and warm season broadleafs in our covercrop, so we have a greater diversity of species that aren'talready represented in our crop rotation. so the more species, the betteras far as the soil food
web, as far as diversityand production. if you look at the image in thecenter at the bottom, it shows a cover crop in montanaafter a frost where you can see some of the species havedied from the frost, while some of the speciescontinue to grow. ok, what about water? this is a question that i getfrom time to time that our cover crop is going to use upour water, particularly in dry land systems, and we're notgoing to have enough water to
grow our cash crop. here in north dakota, westernnorth dakota, some studies that have been done have shownthat we have about a 80% chance of success as faras water is concerned. if we grow a cover crop that'sgoing to use water late into the season, and expect to haveenough moisture the following growing season, you're going tohave to evaluate that for yourself in each partof the world. but generally speaking, thesecover crops aren't using any
more water than we were lettingevaporate from bare or unprotected soil in the past, soit's about a horse apiece. and when we look at how theseplants behave when we have them in mixtures, someinteresting research on a topic called the stress gradienthypothesis, which i refer to on the other twographs showing the five different species in the threefunctional groups. as you grow plants incollections of different species, they collaboratemore than they compete.
the images on the bottom thereshow a turnip cover crop and a reddish cover crop that we'regrowing in some cover crop demonstrations here a few yearsback in bismarck when we had a very dry summer. and where we have the singlespecies of turnip by themselves, or radishby themselves, they pretty much died. they ran out of moistureand died. but where we threw all thespecies together in a mix,
even though we only have lessthan two inches of growing season precipitation, theyflourished and grew. so when we looked at, clippedand weighed what was produced there, we could see by thepounds per acre, that where we had these species all mixedtogether, we had a great deal more production. and those plants were alive,and green, and growing, and feeding the soil food web alot longer period of time during the year than when wehad each individual species
alone in a monoculture. so when you're developing yourcover crop mixes, ask yourself what's the purposeor purposes. there may be more than onepurpose that you want your cover crop to serve. include crop types and speciesthat are not already in your crop rotation, have a minimum offive species of plants, and at least three functionalgroups. and in our part of the world,we found that if we have at
least 20 pounds per acre ofseed, we usually get a pretty good stand withouta lot of weeds. more than 20 pounds per acre isfine, but once we got up to 40 or 50 pounds per acre, werealized that they're probably spending money on seed and notseeing as much return. and so, it's just more of aneconomic reason for not going beyond 40 pounds. but at least 20 pounds and fivespecies seems to work pretty well, at least here andmost of what i've dealt with
in the great plains here. look at your time and method ofplanting, and your time and method of termination. if you can answer these basicquestions, you'll be well on your way to a good covercrop experiment. now this table is in thehandouts, and i don't expect you to be able to read this,but i just took a little snapshot of a table that we usehere in north dakota to help us look at these differentcover crop species
and their characteristics asfar as their rooting depth where they could providesupplemental grazing, things like that, while we'redeveloping these mixtures. another tool that i want to showyou here at the end is available at greencoverseed.com. you can see the web address atthe bottom of the slide here. and not promoting green coverseed as a supplier, but they have a really nice littlecalculator that you can play with to look at how youwant to develop
your cover crop mixtures. and i want to jump to that hereat the end, so you can take a look at it ina live version. so just a few, i don't know ifyou want to take any questions right now, i have justa couple things on some case studies. we have a questionon planting. there's a technique slurryseeding with manure. have you had any observations onthat practice or experience
with that, jon? i don't have any experiencewith it. i haven't seen it done, but ihave read where folks have been including cover crop seedwhen they're applying their manure slurry. and from what i've seen, it'sbeen successful most the time. they haven't had any real bigfailures with it, so i think it would be a very viableapproach to get that done all in one shot.
ok, now in terms of speciesdiversity, there could be some wide variation among cultivarsof certain species. could we count differentcultivars as different species, or would we not lumpthose, not be able to split those out and really need tohave distinct scientific species in that mix? i tend to look at things asdiversity as separate species, but if you did have differentcultivars within a species, i don't see any problem with that,as long as we had enough
overall diversity in the mix. you might want differentcultivars of millet for their different graze-abilityor their different carbon-nitrogen ratios. but i tend to look at speciesas species, and not necessarily cultivars forpurposes of diversity. ok, now on the topic of grazing,is grazing a cover crop compatible with a 340cover crop standard? that i would have to check, butas long as we're leaving
enough residue out there to meetthe goals of what that cover crop was designedfor, i don't see why it would be an issue. good, now, quite a fewno-tillers noticed an increase in slug damage. and there's concern that addingthese cover crops with all this residue and organicactivity, that it could make the slug problem worse. do you have thoughts on this?
we don't have so much of anissue here with slugs, but we sometimes have situationswhere we grow crops that produce a lot of residuelike winter wheat that's very high carbon. and we want to get that stuff tobreak down and cycle before we would go to another crop,where that excessive amount of residue might be an issue. and so we've planted some covercrop mixes that are very low carbon-nitrogen ratio thathave a lot of the legumes,
turnips, radishes, thingslike that, to get that residue to decompose. so while that cover crop isgreen and growing, that might be attractive to slugs, butafter that, it may get some of that residue to decompose whereyou wouldn't have quite the volume of residueon the surface. now, a lot of our audience arein dairy producing areas, and a very popular dairy crop isa pure stand of alfalfa. and so we have during a fouror five year cycle in a
rotation, a single species inthose fields that's really pretty weak on diversity forlong portions of the rotation. have you seen people trying toaddress the diversity, lack of diversity, in some of theserotations, and anything that you might offer asa suggestion for these kind of systems? well, this case study that ihave up on this slide right now from montana, thisindividual had a pasture that was, basically, dominated bycrested wheat grass, a single
species of cool-seasonperennial grass. and it was declining quite abit, so he decided to plant this multi-species cover cropthat included a few additional species of perennialgrasses in there. to not only produce someshort-term forage to save him some money during this droughtwhen he would have had to buy hay, but also to add thediversity to the soil to stimulate that soil and primethat soil so that the grass species that he had outthere would respond.
instead of reseeding the fieldor applying fertilizer, or things like that, he decided touse this biological priming of this cover crop to get thissoil to move to a higher level of biological function toincrease his grass production. and we've done similar thingswith pure stands of alfalfa where we'll drill cover cropmixtures into these declining stands of alfalfa to add thisdiversity to the soil and get it rejuvenated, so to speak,to increase the subsequent production on the alfalfa.
when working with an organicgrower that can't rely on herbicides for weed control,would you recommend higher seeding rates to increase thesmothering performance of the cover crop? certainly, and i mentionedthe 20 pounds per acre as a minimum. if you're concerned about weedpressure, to maybe include some species in your cover crop,such as buckwheat, that tend to be very competitive andup your seeding rates, so
that your cover crop is whatdominates it and gets ahead of the weeds. we look at a cover crop seedingthat has at least 20 pounds and five differentspecies, when we walk out in those mixes, we seevery few weeds. but if we have a lower seedingrate or fewer species, we'll see more weeds out inthose plantings. when we're trying to jump startthe soil biology with cover crops, and we'retransitioning into this
system, would we opt for lowercarbon to nitrogen ratios at below 24 to one? would that help us in the shortturn to meet our longer term soil health objectives? as long as you're carefulto not have such a low carbon-nitrogen ratio that youend up with bare soil would be my caution. so yeah, legumes can bean excellent thing. including species in your covercrop that are not in
your crop rotation is, also,one that has really made a difference in jump startingthe soil biology. you showed a producer mixingmultiple species in the drill hopper. so by mixing something-- different seed size, australianpea, large seed versus with radish and it'sa small seed, is there any trick, or is there difficultyin keeping the species mixed up in the grain bins, it'splanting a number of acres
that we're trying to coverwith a full hopper? we thought that would be anissue when we did some of these, but we realizedthat it really isn't. those seeds don't sortthemselves out as much as you would think they would. if you were planting a mixturethat had very small seeded things like alfalfa or some ofthe clovers, along with some very large seeded things, andnot a lot of other species in the mix, there it might beadvantageous to put those
small seed in a separatelegume box. in a separate box meteredseparately, so that you get a better distributionof your seed. but with these diverse mixes,we have such a range of seed sizes that they really don'tsort out as much as you might think they would. you don't see, jon, you talkabout a general recommendation of 20 pounds per acre with thedifferent sizes of seed. how many seeds are wereally looking to
drop on a square foot? how do we put that in contextof density, and numbers of plants being seeded? i guess i don't usuallylook at those plants per square foot. we calibrate the drill for thatmany pounds per acre and go from there. i don't usually look at it asseeds per square foot, but a guy could sure figurethat out.
and again, exposed with thatdiversity of functional groups, we're going to have somelarge, some small, and well graded as far asfeed [inaudible]. yeah. and one viewer mentions themidwest cover crop council website that serves like six orseven states in the midwest as a great resource for lookingat current research being done in cover-cropping,including the flurry seeding method.
yes. yes, that's an excellentresource. ok, very good. thank you, thank you very much,and i'll turn it back to you now, john, to go on withyour next portion of your ok. so i guess i already told thestory on this little cover crop that was used in montanaon some perennial grass pasture and hay land torejuvenate the stand, so
that's something that we've donein a situation other than just normal cropland. in new mexico, just a quickexample of how they would manage pecan orchards. and now, they're looking at-- they're still using dripirrigation, but they're putting some perennial covercrops in between these rows of pecans, and feeding the soil,and actually, keeping that soil a little bit coolerand a little bit more
biologically active. and it's reducing, particularly,their pest pressure, because there's a lotof parasitizing insects that live in these cover cropsthat will help control the insects up in the trees. so instead of having abiological desert out there, they have some diversity andsome life that actually helps them in their integratedpest management. just two examples from idaho,whether they're using it to
provide some cover after potatoharvest, or provide something for grazing, or justto add some diversity to some of these crop rotations. and some of these are dry land,and some of them are irrigated, but they're doing alot of interesting things just getting some cover out there,feeding the soil during an extended period of time whenthat soil would've otherwise laid fallow. and the last little case studyfrom north dakota here that i
wanted to show on richter farmswhere they had the goals of having soil cover, diversity,increasing soil organic matter on very sandysoils, increasing water infiltration, and nutrientcycling, and integrating livestock into thiswhole picture. so here's the mix of speciesand amounts that they had. and you can see, they wereupwards of 30 pounds per acre with different croptypes, different species in their mix.
and here's what it looked likeback in august of 2007. and when we have when theburleigh county soil conservation district has toursout there, they usually get hundreds of producers. and we've joked about if weever wanted to terminate a cover crop by rollingit, instead we just have a tour out there. and if we have hundreds ofproducers, we could walk them across the field, and they couldroll that cover crop for
us at the same time. ok, so they're weighing thesecalves that they're going to graze this cover cropwith cow-calf pairs. so they're weighing the calves,and they turn these cow-calf pairs out there fora period of 10 days in this and they work their way througheating what they like first, obviously, or whatthey're familiar with, and then working through the otherspecies that are out there. but we're feeding the cows,and we are feeding the
underground herd. so then we weighed the calves atthe end and found that they gained about three poundsa day which is a pretty respectable gain. doing the numbers on that, thenumbers of calves and what they gained, we grossed over$100 an acre by grazing this and then we look at the cost ofthe seed, the seeding, and the herbicide that was usedahead of seeding at $45. and we do the rest of the math,they found that they
made $66 an acre from grazingthose cover crops. now the advantages that theyhad on giving more recovery time on native range land isnot factored into this-- how much it improved soilhealth, and how much it improved the body conditionof the cows-- this is just looking at theweight of the calves. so there are a lot of otherbenefits, but they found they came up about $66 an acre aheadby growing this cover crop and grazing it.
in another situation-- jon, this is mark. i do want to point out thatwe're at 3:06 eastern, so we're well into finishingthe first hour. and so we want to maybe moderatethe final portion of the presentation withthat in mind. so we took water samples, andthis just speaks to the difference of where we had acover crop or no cover crop, and how much water thatwas left in the soil.
and they found the differencewas very negligible. so to have a cover crop or not,the water is still going to either evaporate or grow acover crop, so why not grow a this is what it looked like,made sure we covered the soil, and that should wrap that up. and i wanted to show-- yeah, give them an orientationto the site here, and so everybody can find theirway back there. yeah, i just wanted to givethem a quick look at this
cover crop calculator. you can put in your futurespecies, and then it shows you your carbon-nitrogenratio depending on the maturity stage. how suitable it would be forgrazing, et cetera, gives you an idea of pounds peracre, cost per acre, that sort of thing. so it's a really handy tool touse when you're looking at developing a mix.
very nice. greencoverseed.com. now, one more question came in,and i don't think we can really do it justice. but for the 300 plus peoplewho've tuned into this, i think it's a very interestingsituation that we're all dealing with. while we can clearly see theadvantage of cover crops and soil health and many other goalsand purposes that the
cover crops are serving, we knowthat it's still a very small percentage of farmersusing cover crops. so what can we do? what kind of effectivestrategies can we develop to demonstrate, to show farmers, tohelp them begin adoption in a big way, so that we can reallyget through to the majority of farmersin short order? this is something that we're allfacing in various parts of the country.
i think the key to thatis to start small. we work with our producers, andwe come up with some of these ideas for purposes forcover crops or mixes, and we have them start small, inhowever many acres they can feel comfortable with taking arisk of spending the money and the time to plantthese mixtures. and then see how they work, andthings that don't work, we learn from just as much ofthe things that do work. but we tell them, don't dothis on your whole farm.
pick a field, see how it works,get things figured out before you would move on todo it more extensively. so for farmers to experiment,and then have tours or demonstrations where thatinformation can be shared, has been very effective. and eventually, producers willdo it on more and more acres. ok, very good, and we appreciatethis presentation this afternoon very much. thank you very much, jon,and thank you all
for tuning in today.