I’m Dave Franzen. I’m one of the
Extension soil specialists at NDSU I was charged to talk about deep
banding and where that fits and what that’s all about. So there’s really two big reasons why a
person might consider deep banding and they may not even be what you’re
thinking about, but the two big reasons are first of all,
if you’re wanting to save soil and build structure and and use your
nutrients more efficiently and all those good things and you decide to go into a
modified no-till system for your corn and soybeans, then you’re probably looking at
a strip till unit like, you know, what you’re gonna see all over this place
today. So that’s the thing and they’re all set up in one way or the other to
deliver fertilizer deeply into the soil. So if you’re already set up with one of these things, it’s just kind of a no-brainer that you know just go ahead
and put your P and K in and if it’s the right time of year maybe the nitrogen down and save a trip across the field cause we’re all about that. Right? We all want to save
time, money, and all those kind of things. So that’s the number one reason. The number two reason is more of an environmental plus economic reason. That is the
alternative, of course, is to broadcast it over the surface probably and in
Minnesota, which most you you’re from Minnesota, you have this entity called
the Minnesota Pollution Control Board. Right? And so the last thing you want to
do is have somebody knock on your door and say “I’m from the government. I’m here to help.” So the less you have that kind of situation going on, the
better I think everybody would be. So that’s the thing. If you put the
phosphate on the surface and you have, let’s say, you do it in late fall and then
you have snow or rain or whatever or mix of everything and I’ve seen it
all in this area at that time of year in November, then you’re going to have some of the phosphorus move off your field either by itself or with the soil and
and that’s not good environmentally, because your lakes and eutrophication and all that,
but also you know you’re paying, what, $500 a ton for MAP? I mean, I think if I were you, you’d
want to make sure that if you paid per pound of P2O5 that actually was going to be on the field the next year and one way to ensure that for sure is to put it
underneath and then whatever happens in the fall of the year your phosphorus loss is minimized. Those are the big two. So you’re thinking what about efficiency? So back in the eighties when
the idea, the most recent idea of deep banding phosphorus and potassium was born, there were a few studies out of Kansas and I think Bill Denkey worked with NDSU
back in the 80s and 90s played around with a little bit. In
the first few trials that were done it looked like there was a nice efficiency
factor, but a good friend of mine, old colleague that’s retired now you he said
that if you really want to be excited about research you’d end it after one year
and if you really want to do know the truth, then you do it more than one year.
The truth is that over the span of all the studies that have been done across
the midwest, all over, is that there’s really no efficiency advantage of deep banding compared to broadcast. You say, well if you’re banding in your system like this or you’re broadcasting in your system like
this what happens is you get what you call stratification, where the soil test
P and soil test K, they’re all elevated in the top inch or so. So
isn’t it better to have the nutrients mixed in the lower layers? And
this freaked a lot of soil scientists out in the seventies when the movement,
mostly grower based, was going on about zero till. They said, we can’t do this
because we’re going to stratify these nutrients and crops are going to go deficient, and it’s going to be a disaster and so they set up these long-term experiments
and you know after about 10 years they were like the crops really don’t care where it is as
long as it’s there. To some of you, that may not make any sense. You know you get all the nutrients in the top inch or two and you know you’re depleted down below. So what happens in a dry year? Okay, so let’s talk about what happens in a dry year.
In a dry year, of course you know after about two weeks or something
like that, that top couple inches or so is going to be dirt dry, and so at that period of time, if you had something deeper, it would be more available to the plant, but that deeper moisture only sticks around for a
short period of time, another week or so, and that 8, 10 inch, 12 inch area is dry, too, because the crop has been pulling moisture out of the ground and so it’s just as dry as what it is on top. So what kind of weather conditions do we have
during a dry year? During a dry year, we get, you know, a little piddly tenth. We get a
quarter-inch, you know. Maybe if you’re lucky you get a half-inch. Is that enough to wet down a foot in the soil? No, it’s not, but it wets up the top. Right? And so I think
that’s why we see then these long-term experiments have really no difference
between putting the phosphorus and the potash deep or putting it on top is because even
in the dry years there’s enough moisture at the surface for those little root hairs and the
hyphae of the corn plants to pick that up and they’re okay. So efficiency? No, I
mean it’s not really a reason, but if you don’t believe the science, I don’t really care if you do or not, there’s other reasons why putting it down like I said before, the
environmental reasons and the economic reasons and the idea that maybe you have already a unit that’s going to go across the field like this, a strip tiller and
so just go ahead and do it. So there’s nothing wrong with deep
tilling but if I was going to pay for a special trip across the field in order
to get that P and K lower, I wouldn’t do it, but if I was going to go across field
anyway, then go ahead and do it. That’s fine. The next thing is about how deep is deep? We’re not talking about the little bit of P and K that we might put with the seed or near the seed you know which we all do because we’re all north of DeKalb and if
you don’t know what that means ask your neighbor because you probably heard my
story before, but what we’re talking about is is that deep placement. So what
about deep? What, if you’re using one of these things, how deep should you really
really go? Well the one thing you don’t want to do is you don’t want to go into
the spring of the year and plant the seed into that concentrated band of
fertilizer that you put on the previous fall. There’s still salt. There’s still urea. There’s still ammonia, there’s still stuff, so you don’t want that. So you want enough
distance and with just P and K, a couple inches difference is enough. You’re going to plant the seed, does that mean that in the fall of the year, you just put it two inches
below that? And the answer is no, because over the wintertime things settle. Right?
So a two inch difference in the fall might mean only, say, an inch difference
as you go into spring. Okay, so the question was we’ve had a lot of dust move in North Dakota and a lot of the phosphate, I got a lot of people’s
attention because, and it’s true, that a lot of our native fertility went off
with the dust and so the question is, where does the dust go?
As an aspiring oceanographer in high school, I read a
lot of stuff about core sampling in the Atlantic Ocean and that they
could figure out how many years that core was old by the number of layers.
Guess where some of those layers come from. They come from North Dakota, so they go in the Atlantic. That dust travels thousands of miles all over the
place. Only a small amount ever gets in the ditch. Only a small amount
ever gets to the neighbors. A large amount goes a long way away. Back in the thirties, one of the ways we know how valuable that dust was, is that you could go out in the
Central Park in New York and pick up North Dakota soil by the spoonful
and bring it into the lab and analyze it. I mean 1,000 miles. Dust storms of any
size, not just what you see running across the road, but they have a
three-dimensional height to them. With the very serious dust storms back in the thirties, there
were pilots going into Bismarck that told the people that there was
significant dust up to 14,000 feet. We can, with the satellites now, we can see
dust storms from space so you can go online and look at dust
storms in the Palouse, dust storms in western China in northeast China in any
place in the United States where you hear that there’s some dust storms around and you can see the three-dimensional aspect of all those storms. Even our
little dust storms have a three- dimensionality to them and the most
nutritive part of the dust is the part that’s way up in the air. The crap is
down along the soil surface and that’s the stuff that gets in the
ditch, the large particles, but the real fine stuff with all the nutrients, its
way up there. So the question is what’s the maximum amount of P and K that you put down deep placement? That answer is at
the core of any consultant question. So the answer depends on price of corn,
price of phosphate, the farmer’s financial condition, what that financials ownership
or non ownership of the land is, what their personal philosophy in farming is.
Are they going to will the farmland out to a son or daughter? Is
it going to stay in the family or are they going to sell off to some hunter in Chicago or something? All of those things come into play and so what’s the answer? The answer is as
much as all of those all those factors will allow you to put on. For seedling
protection? You know, I don’t know, there’s probably no practical reason to put more
than three or four hundred pounds of MAP or three or four hundred pounds of potash on. As long as you have the separation, the crop will stand it fine. The damage to the plant is not with the roots, because of its too hot, it’ll
just grow around it. The damage to the plant is at the seed
level. You know, the salt with the seed, because it’s a living thing.
If there’s too much salt, it won’t imbibe water, it won’t grow and if there’s ammonia in it, it’ll
kill the seed just like that. A part per million or two of ammonia and that seed is history.