Steve Larocque is a recognized agronomist, has travelled and spoke around the world.
I personally know Steve and in fact he lives in Three Hills.
Steve has been wondering about distribution on large drills and took some measurements this spring which he published in his most recent weekly newsletter:
Accurate metering but poor distribution
Today's air drills aren't delivering
When it comes to metering seed and fertilizer on todays air drills I like to think we’ve come a long way. Today’s air carts can meter large volumes of seed and fertilizer with varying densities fairly accurately. However, the real problem is not the metering of product but the distribution of that product once it leaves the meters and enters the air stream. My partner in crime Oscar and I set out to measure the performance of five popular air drills.
The air drills we chose were a 60ft Morris Contour 2 with 8 Series 650 tank, 56ft John Deere 1870 with 1910 tank, 76ft Bourgault 3320 with 6700 tank, 70ft New Holland P2070 with P1070 tank and a 70ft SeedHawk with the 800 tank. We zip-tied socks on one long and one short hose coming off the same manifold on the left wing, right wing and center section (six socks in total). We then engaged the clutch for 10 seconds and measured the weight of the product in each sock to compare. From there we calculated the average product weight of all six runs and then measured the difference of each run from the average.
Disclaimer: This experiment was NOT a true scientific test but provides an awesome starting point for discussion.
If you look at the table above you’ll see that each drill has a large degree of variance in product distribution and in many cases on the same distributor, not just from wing to center section. The cells marked in yellow show the lowest amount of product delivered below the average. The blue cells show the highest amount of product delivered above the average. I’ve included the spread between highest and lowest product distribution to show the degree of variance. Here is a summary:
Every air drill had a great deal of variance in product distribution across the drill and in many cases on the same manifold. The range in distribution for all the drills was 29% to 98%. Meaning, some shanks received 29% less than other shanks and up to 98% more than others. Yikes! (Yes, we checked for plugs and obstructions in the lines.)
The best performer in this test was the Morris 8 Series 650 tank with a low of 12% below the average and high of 17% above the average for product distribution. Coincidently, Morris is the only drill with a different manifold design that doesn’t force product to turn 90 degrees when it leaves the primary hoses.
The drill with the largest degree of variance in product distribution was the Bourgault 6700 at 98% between low and high product rates. One shank delivered 71% less product than the average with another shank delivering 27% more than the average.
To be fair, if the issues were corrected on the Bourgault, its variance would be in line with the SeedHawk and John Deere.
The Bourgault and John Deere drills delivered more product to the center section compared to the wings.
The John Deere delivered more product to the center section compared to the wings and had a 45% difference in product distribution from low to high.
The NH P1070 tank was second to the Morris at 33% variance from high to low.
The short hoses on the P1070 delivered more product than the long hoses regardless of position on the frame.
The SeedHawk was in third place on the list with a 41% variance from high to low product rates.
The SeedHawk delivered more product to the wings compared to the center section.
In the end, this little investigation has confirmed my suspicion. Very often there are wide variances in product distribution across rows, distributors, center sections and wings. The Morris 8 Series 650 tank was the most consistent of all the drills. As I mentioned before, Morris is the only drill that uses a different distributor system compared to the other four drills, which use the same style. What surprised me most was the difference from wings to center sections where some drills like John Deere deliver more while other drills like SeedHawk deliver less product to the center sections. Perhaps some repositioning may fix some of this issue.
What is clear from this test is that product distribution technology needs to advance. Why meter product down to the kernel only to lose all accuracy by the time it hits the opener? The best drill in this test still had a 29% difference in product distribution. That’s equal to one opener receiving 20 lbs/ac of starter phosphorus (P205) and another receiving 30 lbs/ac. With nitrogen it would be equal to one opener receiving 80 lbs/N/ac and another receiving 98 lbs/N/ac. On the other drills the differences would be worse.
Note: SeedMaster, which we didn’t get a chance to measure, has an edge over the drills we tested due to its UltraPro meter, which sends seed directly from the meter to the opener with no towers in between. However, SeedMaster still uses a manifold system like the other drills we tested to distribute fertilizer, so it’s possible that it has the same variance as the drills we tested.
From this study I think it’s high time for the seeding tool industry play catch up and start matching the accuracy of distribution to the accuracy of their metering. Good enough is no longer good enough, especially when you consider the $130,000 to $250,000 price tags on these air carts. If we truly want to elevate yields, I believe that every furrow should have equal access to the right amount of seed and fertilizer. It's clear to me now that we have some serious distribution issues to overcome. SL
Big thanks to Jerry Berreth from JHB Farms who graciously loaned me three pairs of his socks to use in this experiment.
Hmm...
