Variable rate drilling transforms arable crop growth stages

Many farmers face different soil types in the same field and achieving even crops can be a yearly battle. However, precise placement and variable seed rates have been a game changer for one Midlands farmer.

Of all the advancements in arable crop production and establishment over the past several decades, Staffordshire farmer and contractor Rob Deane places variable rate drilling, running through his Kuhn BTFR 4m combination drill, as one of the most important.

It’s a system that Rob has used for 10 years, and he says it’s transformed the arable side of the business, guaranteeing even establishment and crop growth for improved management accuracy.

“I believe it’s the biggest step forward we’ve made in arable farming, second only to adopting GPS,” says Rob.

“I’m using detailed soil maps, combine yield data, and my knowledge of fields to form prescription seeding maps that vary the quantity of seed across the field to achieve even crops. The outcome is consistent crops that are easy to manage and have greater yield potential.”

Rob farms 600ha, consisting of owned, rented and contract farming land, from his base at Walton Farm, Eccleshall, in Staffordshire.

Alongside the arable acreage, he runs several high-capacity round combination and larger square balers, as well as having 300 ewes and 120 beef cattle.

He says the huge yearly variations in some crops, that were established on the same day in the same field, meant he wanted to understand if variable seeding could deliver a more consistent crop.

“In some fields, we change from heavy clay to fine glassmaking sand in just 30m. This is partly why we’ve always used a Kuhn combination drill as it’s the logical solution to an even seedbed in nearly all conditions.

“However, a blanket seed rate across the field was leaving the heavier areas with gaps and patchy growth, which didn’t match the lighter sandy parts.”

This led to fungicides and other sprays being applied when parts of the crop weren’t at the right growth stage.

“Rob was keen to try and correct this and the variable rate capability on his current Kuhn BTFR 4030, and previous 6030 model, allowed him to try variable seeding. His new folding BTFR 4030 is fed by a Kuhn TF 1512 front tank.

Vistaflow seeding

Rob already uses variable rate application on his Kuhn Axis fertiliser spreader for phosphorus and potassium inputs.

These are based on soil tests and zone areas of the field to receive the required amount to either maintain or raise levels, as dictated by the mapping.

As the spreader passes across the field, the system adjusts the rate to either side of the machine.

The principal is the same with drilling and the farms are soil mapped with records going back eight years.

From the maps, Rob, along with his agronomist, decide what areas will benefit from a lower seed rate but still achieve the same yield and quality.

Conversely, where the soil is lighter, it could require more seed to increase tillers and outcompete weeds. The goal is even crops that consistently reach growth stages at the same time. 

“By doing this, we can push each field harder as we are making the seed rate work for us,” says Rob.

“Not only are we getting more from the seed, but the fertiliser and sprays are also applied to the crops at the right time.

“In some fields, the seed rate can vary from 240kg/ha to 150kg/ha and it does take a bit of trust in the system early on, but the results speak for themselves.”

Rob says the evenness of crops has been the biggest benefit, while his input costs haven’t changed, the advancement in crop genetics and varieties is allowing him to do more with the same acreage.

“We start drilling on the 1^st September as we have 500ha to cover with the combination drill, so we can’t leave it much later. If we miss the opportunity, we have to wait until the spring, as the land is very unforgiving.”

Precise placement

One area Rob highlights as essential to achieve the results is the Seedflex coulter bar on his Kuhn combination drill.

The detachable Seedflex unit has offset double discs, and a following press wheel fitted on a parallelogram linkage design, allowing the operator to control the depth and pressure of each individual seeding unit.

Each unit is offset by 350mm from its neighbour for soil and trash to flow through the machine and coulter pressure can be adjusted up to 45kg per unit based on the soil type.

Rob says this was an essential feature when purchasing his new drill.

“We had the Seedflex coulter bar on our last BTFR and it made such a difference to repeatable seed placement.

“This is directly related to establishment and how the crop emerges and reaches early growth stages. Having a consistent drilling depth, in a variety of soils, is essential to maximise the variable rate drilling.”

For the operator, setting up the drill for variable rate drilling compared with blanket applications is very similar.

The BTFR runs through the tractor’s Isobus system and, once the maps are uploaded to the tractor, the interface will work out the seed requirements based on the 1000 grain weight calculation.

This means the right seed is put into the drill to avoid having left over grain once finished.

Rob uses variable rate drilling across all his crops, even the oilseed rape. He says that some of his contracting customers have moved to variable rate drilling after seeing his success.

“Using technology that can make the most of our inputs is essential. Some of my customers have the same soil challenges, so we are tailoring how we work to maximise the outcome.

“Variable rate drilling is just one of the tools we use, but it’s proved effective in many ways,” concludes Rob.