Variable-rate seeding next step in precision farming

Seeding & Tillage Focus: Southwest corn grower reports higher yield and lower seed costs

Boissevain-area farmer Arthur Bell recently stepped up his variable-rate game.

After accumulating seven years of experience with VR fertilization, three years ago he decided VR seeding would probably work much the same way and give him similar results.

The basic strategy is the same — identify the most and least productive spots in each field and match seed rates with yield potential.

“Some areas of the field have more organic material, or are just better areas that can support a higher plant population,” said Bell. “That was the reason I decided to try variable-rate corn seeding because I can maximize my plant population in good areas, and in the drier areas where moisture is normally a limiting factor, I can cut the population back.”

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The first year Bell saved about 16 per cent in seed costs, and he estimates he’s getting around 10 per cent higher yield in the most productive areas where he increased his seeding rate.

Lots of interest

Jamie Denbow, Farmers Edge’s product manager for decision support services, said around five per cent of the growers he works with are doing VR seeding at the moment, but interest is rapidly growing every year, especially in crops with a high seed cost like corn. Some growers have also used it for lentils, wheat and soybeans.

“It’s really starting to grow as more equipment with VR-capable technology gets adopted,” says Denbow.

Although every farmer wants to save on input costs, VR seeding is more about farming more efficiently and sustainably.

“They’re trying to take the right seed, at the right amount and place it at the right place, matching the seed quantities to the productive capability of the land,” Denbow said. “If an acre has the potential to grow 150-bushel corn and I can grow that with 30,000 seeds per acre versus 35,000 seeds, my efficiency is that much higher. So I’m controlling my cost while maximizing the yield capability on each acre of the farm.”

The applied work behind VR seeding will also be familiar to growers using VR fertilizer strategies.

“We start with satellite imagery that tells us where the zones of differing productivity are, then we physically soil test each one of those zones to find out what the structure, texture and native amount of fertility is in that piece prior to seeding, and then we implement our strategies around those numbers,” Denbow said.

A comfortable starting point for many growers is to take their standard seeding rate and go plus or minus 10 per cent from that. After doing VR seeding for a while, they tweak it to a wider range, Denbow said.

“As an example, if you have five different soil productivity zones on the farm, the standard seeding rate would be in the middle — a zone three. A zone two might be minus 10 per cent and minus 15 per cent in a zone one, and then plus 10 per cent in a zone four and plus 15 per cent in a zone five. Growers could have a seeding rate that’s as much as 30 per cent variation within the same field,” Denbow said.

Most of today’s farm equipment has VR capability, and older equipment just needs a rate controller to manage seed and fertilizer independently, and two or more tanks on the seeder will make it easier to do.

Trials will refine

The next step in VR seeding is understanding how different varieties behave depending on plant population and conditions.

“In the U.S., growers have new corn and soybean planters with two tanks and they’re putting a different hybrid in each tank and seeding different acres of a field to different hybrids based on their understanding of how those hybrids respond to the conditions that are available on those acres,” said Denbow. “We don’t have that level of understanding here yet, but we’re doing trials this year taking multiple different corn hybrids, seeding them in the same field and studying how each one behaves. With that information, we can begin to tweak our practices accordingly.”

Bell is going to also host a field trial on his farm, and he wants to try variable-rate seeding on soybeans.

“I had problems with white mould in the back areas of my fields in the soybeans last year, so it’s almost the opposite situation where in those areas I want to cut the population back a little bit because when you get a better stand it’s sometimes more susceptible to white mould,” he said. “Each crop is different, so you have to adjust a little depending on what the crop is.”

Denbow doesn’t know of anyone who has tried VR seeding with canola, and he questions if results might not be as significant as in other crops.

“Canola is a plant with high plasticity, which means if you give it a lot of room, it becomes a big, bushy plant,” he said. “If you give it less room, it becomes a tall, vertical plant so it adapts to the space it has. Whereas crops like corn produce one tall stock, so it’s not as plastic.”

All farms

Any grower — regardless of farm size — can do VR seeding as long as they have the equipment, and are able to analyze the data, Denbow said.

“In some cases the grower may not save anything on seed costs, he may end up using the same amount of seed, but he’s placed the right amount on acres that have the capability of producing higher yield with that seed,” he said.

To truly understand how the system pays off the best way to compare is to overlay a cost map over a field map, Denbow said. It demonstrates how yield and inputs combine for a higher overall yield, and also adds to the farmer’s knowledge base.

“(That) grower will have a great deal more data which is going to allow that grower to make more informed decisions,” he said.

Bell said he’s getting the most efficient use out of the seed he’s putting in, and because corn seed is expensive he’s seen a quicker return.

“Variable-rate seeding — just like VR fertilizer — is about maximizing the inputs you’re putting into the ground and getting the most out of them.”

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