Committed to carrots? Forget the old advice and think carefully

COMMITTED TO CARROTS? FORGET THE OLD ADVICE AND THINK CAREFULLY IN THE FUTURE, PROFITABLE CULTIVATION WILL DEMAND A NEW APPROACH. IT WON’T BE ABOUT FALLING BACK ON HABITS AND GENERAL ADVICE BUT ON NURTURING SOIL LIFE AND PLANTS’ NATURAL RESILIENCE. THE CONCLUSION OF THREE CROP EXPERTS: “GROWERS NEED TO LEARN TO GROW AGAIN.”

“The biggest challenge, in my opinion, is the changing climate.”

Sander Bernaerts

Carrots have always been an intensive crop. Under optimum conditions, growers can get 150 crates per hectare. High yields with good storability don’t happen automatically, though. It takes the right efforts in fertilization, disease and pest control, land preparation, and – now more than ever – irrigation.

This crop has the potential to deliver great returns, but cultivation costs are high. In addition, the market is demanding, and the use of certain chemicals and fertilizers has come under pressure.

So the question arises: what do growers need to do to make sure cultivation remains profitable in the future? Bejo asked three experts with different areas of specialization who provide practical growing advice daily. Sander Bernaerts is an advisor in organic vegetable cultivation and agriculture. Chris van Laarhoven is a soil and fertilization specialist in conventional and organic horticulture. And Pius Floris is a recognized soil biology expert and founder of the company Plant Health Cure, which produces soil fungi, soil bacteria and plant-based products to boost plant resilience.

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BEJO CARROT MAGAZINE

“As far as I’m concerned, we can throw out the old rules on fertilization.”

Chris van Laarhoven

The three experts agree that carrots are shifting from an open field crop to a horticultural one. With circumstances on the field changing, a one-sizefits-all approach to sowing, fertilization and harvesting no longer suffices.

Climate change

What’s the primary reason for the changes? “The biggest challenge in carrot cultivation, in my opinion, is the changing climate,” Bernaerts says.

“We’ve had three extremely dry springs and summers in a row. This year some growers watered more than 100 mm around planting just to make neat ridges and get the crops to come up. We’re also seeing droughts alternating with heavy rains, causing the ground to compact. If this continues, it will be extremely worrying.

“What farmers can do to compensate is take care of the soil. Growers need to do everything they can to stop soil degradation. Don’t go out on the land with a 6-cylinder tractor if you can manage with a 4-cylinder.

Include enough resting crops in your crop plan, and think about the effects of previous crops on the carrots. Use more solid manure to build up organic matter. Basically, everything needs to be right, especially with a crop like carrots.”

Growers like to see full, green plants. And they look good, but you can’t sell leaves. Plus they attract unwanted insects. I advise a minimal initial dosage, and after that you want just enough over the course of the season to keep the foliage green. Because you do need a bit of growth; it helps to prevent mildew, and the foliage needs to stay strong enough for lifting.”

Fertilizer

Natural defences

Van Laarhoven says, “I’ve been telling growers for 15 years that they use too much nitrogen. And they say, ‘Just to be sure. It can’t hurt.’ I always say, ‘The only thing you can be sure of is that you’re using too much.’

“The most important factor for storage quality is resistance in the crop,” Van Laarhoven says. >>

The key to profitable cultivation in the future, the three experts agree, is a willingness to let go of habits. For example, they point out that a lavish use of nitrogen fertilizer is counterproductive.

Plant nutrition is important not only for growth and yields but also for resistance to diseases and pests. Here, too, there are things growers can do.

BEJO CARROT MAGAZINE

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“Plants need to be able to produce their natural defences against fungi. To do that they need cobalt and silicon. And calcium is important for the uptake of these trace elements. It sounds simple, but it’s not, because interactions between nutrients are a factor. For example, calcium absorption is inhibited by an excess of potash. That’s why we recommend never applying potash with the initial dose. Plants only need potash between the 4- and 6-leaf stages. And you should only supplement if there’s a deficiency, using a low-chlorine potash fertilizer.” The commonly used agricultural fertilizer Kali 60 is disastrous for carrots, the experts say, because the chlorine harms soil life.

Healthy soil

Floris believes the reason farmers use so much fertilizer is that they lack confidence in the quality of the soil. “Synthetic fertilizer makes plants sick,” he says. “I compare it to fast food. It might taste good, but if all you eat is hamburgers, you’ll make yourself ill.

It’s a stubborn misconception that nutrient absorption comes down to availability. That’s the chemical approach. The reality is that plants absorb nutrients through interaction between their roots and fungi in the soil, and artificial fertilizers largely render them unable to do that. Fungicides cause damage too. They’re used in conventional farming to treat harmful fungi. They do what it says on the tin: kill fungi.

Unfortunately, that includes a lot of beneficial ones. Let’s face it, once soil organisms are gone from a field, they won’t come back on their own.”

That’s because the remaining organisms will rush to fill the space – and they usually aren’t the ones you want.

“We advocate giving the good fungi a helping hand,” Floris says. “Biostimulants prompt plants to fight the causes of disease and infestation themselves. And that means you’re improving soil quality and crop resilience.” The products his company, Plant Health Cure, sells include ones that support the colonization and growth of mycorrhizal root fungi.

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Resilience

These experienced experts agree: successful cultivation depends on healthy soil and crop resilience. ”Many growers have become too dependent on chemicals,” Floris says.

“The use of synthetic fertilizers and biocides has severely impaired soil quality for many growers. Repairing it is a long-term process. But once you start, you’ll see a difference after a year.”

Van Laarhoven adds, “As far as I’m concerned, we can throw out the old rules on fertilization. Thinking in terms of biology is better, but really we need to switch to systems thinking. It’s about activating processes in the soil without having to chuck in all sorts of stuff.”

Bernaerts says, “General fertilization advice is still valuable, but farmers need to think for themselves too. What do you need for a resilient crop in your situation? How will soil life be affected? And measurement is part of it. I’m surprised when growers spend hundreds of euros per hectare on fertilizer without taking a soil sample.“ Debates and discussions around cultivation still often focus on spreading and spraying, but especially in light of the changing climate, it’s becoming more important to talk about the soil and cultivation itself. It’s all about aspects like soil fertility, tillage and sowing techniques.

“The use of synthetic fertilizers and biocides has severely impaired soil quality for many growers.”

Pius Floris