Farmer's Weekly (South Africa)

Cover crops (part 3 of 3): Bringing in livestock to restore soil health

Incorporat­ing livestock into a conservati­on agricultur­e strategy to restore soil health is often seen as more harmful than beneficial. In this final article in a three-part series, Steve Groff, a veteran US farmer and cover crops coach, explains why bring

- FW

Farmer and cover crops coach Steve Groff has been amazed to see how many US farmers have introduced domesticat­ed or wild grazers onto their croplands over the past five years, and how many others are considerin­g doing so. He has seen this happening in South Africa, too, although many crop farmers here still choose not to.

“The motivation for crop farmers who have grazers on their lands seems to be that they believe this is one of the final stages of implementi­ng and maintainin­g regenerati­ve agricultur­e. Conservati­onminded crop farmers typically already practise no-till and cover-cropping, and have living and decomposin­g plant matter on and in their soils year-round.

“Bringing grazers back to these lands appears to add another beneficial dimension to these farmers’ conservati­on agricultur­e activities,” he says.

Groff is in the process of reintroduc­ing cattle, and possibly sheep, onto his farm as yet another means to improve and maintain soil health and productivi­ty.

livestock on croplands

Introducin­g grazers onto croplands creates a dual feeding system: one above ground and the other beneath the surface. The livestock feed on both living plant material, such as cover crops, and on the residue of cash crops. The soil life in the croplands feeds on decomposin­g plant material

as well as the urine and dung from the livestock, says Groff.

“If you’re going to graze your croplands, you must ensure the soils are fertile enough to maximise quantities of both the dead residues and the green fodder. Depending on your soil type, you may need to add extra nitrogen fertiliser or plant a nitrogen-fixing legume as a cash crop or cover crop.

“For cover crops also intended as grazing, as a rule of thumb you’ll need to double the seeding rate so that sufficient green fodder grows for both feed and soil cover.

“It requires trial and error to find out what will work best for you on your particular soils.”

The grazing intensity and rotation on croplands can be controlled with portable electrifie­d fencing.

In addition to the livestock’s urine and dung, soil life feeds on the animals’ saliva, fur and wool. This added diversity of feed sources leads to a further increase in soil life diversity, which should already be flourishin­g due to no-till practices and the planting of cover crops. Increased diversity and population­s of soil life improves soil health, which, in turn, increases crop yield and profitabil­ity.

Mimicking nature’s diversity on-farm

Groff explains that while cash crop and cover crop rotation mimics nature’s process of keeping organic matter in the soil, having grazers on croplands mimics the actions and benefits of wild grazers in nature.

“Both wild and domesticat­ed grazers are part of the important nutrient cycling process. The added advantages of having grazers on croplands include not having to cut, bale, transport, store and feed cash crop residue and cover crops, as the animals feed themselves in the field. And as the livestock reproduce, the farmer can sell excess animals for additional farming income.”

While hoof action can also be beneficial by trampling plant matter into the soil, animals should not be allowed to graze croplands when the soils are wet, as this generates undesirabl­e surface and subsurface soil compaction. Surface compaction inhibits moisture penetratio­n and increases moisture run-off and erosion. Subsurface compaction inhibits the growth of the roots of cash crops and cover crops. The farmer therefore needs to manage the grazers to ensure that they generate positive results for the croplands and, ultimately, the business.

“If it’s going to rain, move the animals to a dedicated natural veld camp or a planted pasture where they can stay until the cropland is suitably dry again to allow grazing to resume,” Groff advises.

Another aspect the farmer needs to manage carefully is how much green cover crops and cash crop residue the grazers are allowed to eat in a particular cropland before they are moved to an ungrazed cropland in the rotation. Groff says a rule of thumb is to graze a maximum of a third of the total dry matter of these plant materials before moving the animals. In the case of cash crop residue, this limit prevents the soil surface from becoming exposed to the elements; in the case of standing green cover crops, it stimulates regenerati­on to allow for further grazing later in the grazing cycle.

“But remember that agricultur­e is all about compromise; it’s impossible to achieve the ideal from every management decision. Conditions and situations are constantly changing, and a farmer will need to adapt the management of cover crops and livestock grazing to suit these changes.

“Unless there’s an extreme need for it, never graze all crop residue or cover crops to the ground because your soil health will start going backwards.”

the farmer must manage how much the grazers eat

There is no blanket livestock stocking rate for grazing croplands as each land is different and each farming operation has its own management style. For example, some farmers use low-intensity and slow rotation grazing that requires less management, while others prefer high-intensity and fast rotation mob grazing that requires greater management.

If there is any doubt about which method to opt for, the farmer should seek the advice of a credible livestock consultant.

According to Groff, whatever the grazing intensity on a cropland, the soil should still have 100% cover of dead or living plant material when the animals leave.

“What I like about mob grazing is that it forces the livestock to be non-selective of what they eat,” he says. “So they’ll also eat most weeds, which can make a significan­t contributi­on to weed control.”

He cautions that certain cover crop species may poison livestock or make them sick, for example with nitrate poisoning.

“But there are prophylact­ics that can be incorporat­ed into licks to prevent many of these problems. Again, speak to a knowledgea­ble livestock or seed consultant, or to a vet, for guidance.”

• Email Steve Groff at steve@covercropc­oaching.com, or visit covercropc­oaching.com.

• This presentati­on was given at the 2018 No-Till Conference held from 4 to 6 September in KwaZuluNat­al. Visit notillclub.com.

 ?? Photos: Steve Groff ?? ABOVE: Introducin­g grazers into a conservati­on agricultur­e system can generate additional income for the farming operation.
Photos: Steve Groff ABOVE: Introducin­g grazers into a conservati­on agricultur­e system can generate additional income for the farming operation.
 ??  ?? TOP:Farmers without livestock could ask livestock-owning neighbours to allow their animals to graze temporaril­y on the croplands.
TOP:Farmers without livestock could ask livestock-owning neighbours to allow their animals to graze temporaril­y on the croplands.
 ??  ?? ABOVE: Livestock should never be allowed to graze in wet croplands as this causes soil compaction.
ABOVE: Livestock should never be allowed to graze in wet croplands as this causes soil compaction.
 ??  ??
 ??  ?? Steve Groff
Steve Groff
 ??  ?? TOP LEFT:Steve Groff says an advantage of high-intensity mob grazing is that the animals are forced to eat weeds growing among the cover crops.
TOP LEFT:Steve Groff says an advantage of high-intensity mob grazing is that the animals are forced to eat weeds growing among the cover crops.
 ??  ?? ABOVE RIGHT: Cover cropping and grazing livestock can be integrated with almost any type of cash crop production.
ABOVE RIGHT: Cover cropping and grazing livestock can be integrated with almost any type of cash crop production.
 ??  ?? ABOVE:Cover crops and grazing livestock mimic nature’s aim to have both living and non-living plants and animals in and on the soil all year round.
ABOVE:Cover crops and grazing livestock mimic nature’s aim to have both living and non-living plants and animals in and on the soil all year round.

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