(music) Looking at environment factors that can affect herbicide drift, so the factors that are beyond the applicators control, but the idea being the more we can understand about those environmental factors then maybe the better we can help curb
when the best time are to spray. So back up that with numbers. One of the pieces of data that I’ve looked at recently is average hourly wind speeds across the state of Missouri. So on page 43 you should have a page with five graphs. Yours should be in color
and have less writing on it than mine. I looked at average hourly wind speed, in five different areas of the state. Northwest Missouri, Northeast Missouri, Mid-Missouri, here in Boone County, Southwest and Southeast Missouri. And there’s a graph for each of those counties. And what I did was, I went back and took every April day over the last 14 years and every hour of every April day over
the last 14 years, the average wind speed. And I took all that data and summarized it and made a profile or a line showing what a typical April day would look like,
and that’s in red. The red line on on your graph of interest is the average wind speeds of an April day. So to walk you through the graphs, if you’re looking at the horizontal axis or the x-axis is going to be the time of day. So the three hour mark is 3 a.m. The 12 hour mark would be noon,
15 hour mark would be 3 p.m. and 24 hour mark would be midnight. And along that vertical axis or the y-axis
is your wind speed in miles per hour. And what we found when we looked at all this data, is that within all of the sites that we looked at over the last 14 years the average hourly wind speed from about
9 a.m. to at least 3 p.m. in the month April is above nine miles per hour. Nine miles per hour being kind of the cut off for when you should be applying some of these herbicides and you can
see there’s a black bar that goes across your graph and that would be a nine mile
per hour line. So anytime the line goes above that, it’s kind of… maybe it’s a little too windy to spray. So, Dr. Bradley is a fan of using these 2,4-D and Dicamba programs in burndown applications which we
would be spraying in April, maybe May. And so if you’re going to do that you’re gonna have to go look at the wind patterns. You know, keep that in mind that it is going to be windier at that time. (Kevin Bradley) And that’s the point I failed to mention she just said it but I’ll just reiterate it.
I’ve said numerous times and I still will say it right now. I think the best utility of the Dicamba resistant soybeans and the 2,4-D resistant soybeans is in the pre-plant burndown for marestail, giant ragweed all those kinds of things. Not necessarily end crop later in the year, although it’s certainly a tool then. But I think the most utility is pre-plant burndown obviously that’s one side of the coin
but the other side is what Mandy’s showing here ten twelve mile an hour winds when we
will be doing the pre-plant burndown in April or May. So it doesn’t really always mesh together there, the two. It’s an oxymoron almost, I guess. (Mandy Bish) So, if you flip to the next page I’m just gonna summarize it briefly. I went ahead and looked at some
other environmental factors that are well beyond the
applicator or the farmers control. As far as things that effect drift risk. The EPA put out a study in 2006 and listed some factors which are on the left hand side of that page. And I took the the county’s that I had done
the wind analysis for and kinda used the 2012 national ag census data to kind of compare that list on the
left with these counties. And so you can read through the list, the four points That fourth point has a question mark by it. It says “more than eight major crops are
cultivated in the county.” Basically only Boone county of these five
qualified as far as high-risk if you eight crops. But the EPA looked at this in a different way than maybe we should look at it. They counted all soybean as one crop and when it comes to herbicide drift potential and with these new soybeans coming off regulation I’m not sure you can count all of soybean as one crop. You have to count the Dicamba soybean as one, 2,4-D as another. And when you start looking at it like that then all the counties get closer to that eight major cultivated crops. And that increases the number of days with risk. So at the bottom of that page the EPA gave an estimate for every county in the nation based on these four points as to how many high-risk days there are during the growing season for herbicide drift. And if you’re counties not there and you’re just curious about the information let me know and we can get that for you. But I wanna switch gears now, finally, and talk about something that’s an environment factor that’s a little harder to quantify and that’s temperature inversions. So, talking with scientists at North Dakota State and just reading some of the publications. It seems like as far as environmental factors go, the temperature inversions might be the predominate cause of herbicide drift, in many cases. And so what a temperature inversion is
is first under a normal day, like today, the Sun hits the ground,
the ground is gonna emit irradiate that heat and so the air near the ground is gonna get warm, it’s gonna expand and it’s gonna rise.
And then the cooler air is gonna come down its gonna get warmed, it’s gonna expand, it’s gonna rise. So you have this constant shuffling of air,
on a normal day. okay? Well when a temperature inversion happens, it’s gonna be… start to happen close to dusk when the suns going down on a clear night where there’s not clouds to kind of trap or contain the heat throughout the night. And what’s gonna happen is the surface is gonna cool faster than everything around it. So it’s no longer going to be
emitting that heat into the air and you’re not gonna have the movement.
So the air is just standing still. So a temperature inversion usually…a sign of a temperature inversion is really reduced wind, a clear night. And what happens is when your spraying during those conditions basically the large droplets are probably
gonna hit the surface that you want but those smaller droplets that tend to be
suspended in the air, in that stagnant air and so if there’s a horizontal wind movement,
or cloud movement, it can carry those suspended particles off very easily. So I’ve listed some signs to look for on the next page, which I think is 45 At the bottom that page,
there’s four things that they say to look for. The presence of dew or frost
suggests that the surface is cooler as the water condenses on the leaves,
you have the wind speed, clear skies and then fog. But what I really wanted was a number.
Like how often does this occur in the state of Missouri? Is it something that we really need to be on the lookout for? So I looked for data, published data, to try
to get that for you and I couldn’t find anything. So then Kevin asked the climatologist if he had any data and he did not have any data. So he sent out an email to his network of colleagues across the US.
And the most common answer we got back was “well that’s a really good question tell
us what you find out about it.” (laughing) So right now we’re setting up a long-term project,
about a three year project, to try to get an idea of how frequent these temperature inversions are across the state of Missouri. And so hopefully maybe this time next year we’ll have some very preliminary results about that from April and May. (music)