Decisions regarding planting, including planting capacity, are among the most crucial decisions farmers face each year.
Dr. Mike Buschermohle, University of Tennessee biosystems engineering professor, has spent several years studying multiple factors impacting planting. Although he sees some trends and potential advantages for planting efficiencies, it all comes down to field shape, size and terrain.
“I ask growers how they define a good planting day,” says Buschermohle. “The answer I usually get is 100-150 acres on a good day with current technology.
“New high-speed planters give us an opportunity to go faster, but what does this technology do for us,” he continues. “The question a lot of producers have is ‘Do I go wider, or do I buy faster?’ Some of the work we’ve been doing is trying to answer that question.”
For starters, Buschermohle notes that growers need to understand planter performance and capacity.
“Planting capacity is a function of the maximum capacity a planter can obtain while operating at 100% of its width for a given speed and planter efficiency at that speed,” he explains. “But in reality, it’s the time you enter a field until the time you leave the field. If I’m running a 40-foot planter at 5 mph, the best I could plant is 23 acres an hour if I’m 100% efficient. But we can’t maintain 100% efficiency, because we have to turn, fold, unfold and load seed.”
In his field trials, Buschermohle determined field efficiency and capacity values across more than 30 fields using planters of various widths at planting speeds ranging from 4 to 12 mph. As expected, faster planting speeds decreased planting efficiency, but increased planting capacity across all speeds and planter widths.
“Field shape and size does influence how fast you can go,” he states. “If I’m planting at 4 mph and can get another 2 mph, I’m getting about 34% in additional capacity. At 3 mph more, I’m at almost 50%. That’s a difference of about 7 acres per hour. Over the course of a 10-hour day, I might be able to get an extra 50-60 acres planted.”
For cotton, the results were similar when it came to planting speed.
“Typically, we’re a little bit faster when planting cotton,” said Buschermohle. “With a standard 38-foot wide, 12-row planter, most folks are planting at 5 mph. From 5 to 7 mph, I saw an almost 30% increase in planting capacity. At 8 mph, I’m getting 40%. By going to an 18-row planter, I can gain about 6 acres an hour. With a 24-row cotton planter, I’m at 28 acres an hour and getting a good increase with the width.
“The question is – can I take a wider planter into my fields, or am I better off going faster? Field shape and size influences everything we do. We are far more efficient on larger fields.”
In addition to speed and width, there are other factors that can influence planting capacity and efficiency. Seed loading, for example.
Buschermohle’s studies show that the standard system of emptying bags into individual hopper boxes takes two people about a minute per box – roughly 12 minutes to refill a 12-row planter. With a seed tender, refill time for individual row units comes down. And with central fill systems, the time to load two bulk boxes of seed drops even more dramatically.
“The crop does make a difference, too,” he adds. “The key is how many acres will the planter plant. For cotton, two bulk boxes in a central fill will plant 400 acres. For soybeans, with a 140,000 seeding rate, it’s only 80 acres with the bulk boxes.
Since most fields are a bit irregular in shape, Buschermohle also suggests that growers who are using two planters – a wide or fast planter, plus a regular planter they’re used for years – may want to use the smaller planter to plant end rows and the irregular areas of the field. “Put the wide or fast planter in the larger areas of the field, and get them in and out of there and move them on to the next field,” he suggests.
More speed may also call for an upsize in horsepower. In general, Buschermohle says a move from 5 to 7 mph will require 40% more horsepower. Going to 8 or 9 mph could increase horsepower needs by 80%. And, it’s important to pay attention to the planter’s down pressure. “It’s critical that we maintain the depth of the seed,” he says. “We do more bumping across the fields at higher speeds.”
With more speed and planting capacity, growers also need to be prepared for faster turnarounds for loading seed and chemicals. And, as Buschermohle notes, maintenance also comes around faster, especially if growers are on a schedule based on acres planted.