Understanding the essentials of cover crops

Farmers always have the desire to get the most out of their crops, but what is essentially needed to be done to ensure that? Cover crops play a huge role in prohibiting soil erosion and enhancing the soil’s quality, giving farmers the best produce to sell.

Cover crops adapt to conventional, low-input, and organic field crop environments with ease. We spoke to experts who share the importance of cover crops.

According to Onele Mduzulwana, an agronomist at Daracorp NPO based in Gauteng, a cover crop is a plant that is planted but not harvested, to benefit the soil and/or other crops.

The advantages of cover crops include less soil erosion, increased soil quality, decreased weed pressure, and decreased insect, nematode, and pest issues. In addition to or between the main farming seasons, cover crops are produced as well.

“We plant cover crops primarily to slow erosion, and it’s not just to slow erosion, but to improve your soil health and fertility while also enhancing your water availability or water holding capacity. It also smothers the weeds, that’s why we do it,” she says.

Timing is important

According to Wafiq Essop, agronomist and soil scientist at Farm Optimiser, timing is such an important component when it comes to cover crops.

“When you plant your cover crop, there is a time when you want it to grow. When you plant a crop, in harvest or just afterwards, you don’t want it to over-compete, so you wanna make sure that you plant a correct type of cover crop, or usually in these bags, these cover crop mixes that you apply,” he adds.

Essop makes an example of the difference between the seasons and sprouting time. He explains that some cover crops sprout during the warm summers, while others sprout during cooler autumns.

“So, you have this constant growth and what you’ve gotta do, essentially, you gotta cut it down or work it into the soil,” explains Essop.

Benefits of cover crops:

According to Netafim agronomist Jovan Erasmus, there is always something in the soil unless it is completely compacted. Importantly, if your soil is healthy, “something’s gonna grow”, he says.

“Obviously you can’t grow them in certain types of soil that are drier. Essentially to cover that gap, many farmers do it. I’ve been to a farmer recently who uses wheat as a cover crop. Now there it can work, but wheat, for example, won’t work in citrus,” explains Erasmus.

At times farmers don’t always want the wheat because it could carry acids and other viruses over.

Therefore, ensure that you get the timing and the type right, he adds.

How to cover orchards?

Erasmus further explains that he can relate to cover cropping in orchards. “What we do, when we generally plant orchards, is we open up this massive area and then you rip, and you till that soil, and you expose this bare soil to sunlight.”

Everything happens in the soil, he explains. If the soil is turned around, the microorganism that lived 40 centimeters into the ground, will not survive at the top because it will be too hot on top.

“You’re basically taking this piece of nature and you’re turning it all around and you’re more or less killing a lot of things. So, the basic idea that I believe in with cover crops in orchards specifically, is you want to stabilize that soil as quickly as possible because you want to stop erosion,” he says.

Getting the most out of your cover crops

To ensure you get the most out of them, Mduzulwana advises the following:

  • Tilt cover crops into the soil before the head forms.
  • Make sure this happens during the flowering stage because the soil is most active then.
  • Allow two to four weeks for the plant to decompose.
  • If the choice is to plant again, go with a green menu (tender and delicate plants).

Essop agrees with Mduzulwane and adds, “These are the main benefits you can get out of that. And obviously, depending on the kind of crop that you have, you don’t want to have a cross fuss. If you don’t have any legumes, perhaps you don’t want legumes or you’re not going to benefit most from them. So, it’s your cover crop combination, it’s the timing. And of course, most importantly, it’s when you work it back into the soil that’s gotta be spot on.”

The idea is to cut the cover crop as close to the soil as possible, to have two options from there onward, says Mduzulwane. The first option is that the plant material is turned, or the roots and you take advantage of the nutrients stored in the plant. The second option is to tilt the whole plant so that you get the best out of it.

Examples of cover crops:

Legume.

  • Red clover:
  • Crimson clover
  • Vetch:
  • Peas:
  • Beans:

Non-legume.

  • Cereals: Rye, wheat, barley, oats, triticale
  • Forage grasses such as annual ryegrass
  • Broadleaf species: Buckwheat, mustards, brassicas

It’s important to know which cover crops will be beneficial for your produce. There are a few questions to keep in mind depending on the expected results.

  • Do you want to add nitrogen to the soil?
  • Do you want to reduce soil erosion?
  • Do you want to provide weed control?
  • Do you want to manage the nutrients?

Asking questions will be the best way to decide what is needed to grow the best produce.

LISTEN TO: Farmer 101: Why should you use cover crops?

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