Growing potatoes with nature

Producing potatoes biologically requires patience. But, as farmer Jan Genis explained to Jay Ferreira, this holistic and sustainable method improves soil health.

Born on the Sandveld into a farming family, Jan Genis has been producing potatoes since 1995. He began on the family farm Laingshoogte and now operates on the farm Hebron near Graafwater. In 2008, supported by his wife Celna, he changed to biological farming and has seen dramatic positive changes on his farm.

Biological vs organic farming

“Biological farming means farming in harmony with nature,” explains Jan. “It’s a holistic, sustainable system that improves soil health, in turn promoting crop, livestock and human health. The three pillars of biological farming are soil biology, soil structure and soil minerals.“It’s not ‘organic farming’. Instead, it aims to put maximum nutrients into the crop to promote maximum health benefits. “Organic farming uses only compost and manure, and no chemicals at all. We sometimes use ‘soft’ chemicals in fertilisers and pesticides, but make sure these complement the soil’s micro-organisms rather than harming them.”

Why biological farming?

Jan explains that when he started farming, some of the land was virgin veld, yet by the third potato planting, production had decreased and disease was on the rise. “We’d always believed that with a good chemical spraying programme we’d get good results, but that didn’t happen,” says Jan. “We used the best chemicals, but our potatoes got every disease imaginable. We needed to change before we lost everything.”

The realisation was the beginning of biological farming for Jan. “I knew there was a better way to farm. A farmer can’t work against nature; he has to put something back into the soil to get something out. The micro-organisms that live in this particular soil are important, otherwise the soil would really just be a medium.”

He points out his experience was not unique. Many farmers in the Sandveld also produce an excellent potato crop in the first year – up to 80t/ ha – but this lasts for only a few years, depending on the amount and nature of the chemicals used. Then disease sets in and production declines, forcing them to plough virgin soil and start again.

Balance

“The first thing I did was to balance the soil according to the Albrecht System,” recalls Jan. This means taking all the cations to their minimum levels and balancing them in a specific ratio. Jan also uses a considerable quantity of lime, which is regarded as anathema in the Sandveld. In fact, Potatoes SA warns against using lime due to the perception that it increases the soil’s pH, resulting in common scab.

Jan disagrees. “pH indicates the balance of all cations in the soil,” he says. “Whenever cation levels are excessive, the pH will be high. Lime isn’t used to change the pH but to alter the balance between the cations in the soil that influence the pH. A high pH is more often caused by high levels of other cations such as sodium (Na), potassium (K) and magnesium (Mg). Once the calcium (Ca) level is built up in the soil, the high levels of the other cations drop and so does the pH.”

According to Jan, gypsum cannot build Ca in the soil until there is 60% Ca saturation in the soil. “Gypsum contains calcium sulphate. This will take Ca out of the soil, so Ca levels must be built up to 60% by adding neutral material such as calcitic lime containing calcium carbonate. The carbonate breaks down into water and carbon dioxide and doesn’t remove calcium from the soil.”

He applies lime just before planting at between 2t/ha and 3t/ ha, depending on soil analysis results. If the soil requires magnesium, he uses dolomitic lime; if it needs calcium, he applies calcitic lime. Jan also applies manure to build up the soil’s organic material content. The manure forms humus, which increases the soil’s capacity to retain minerals, so less plant nutrition has to be added to the soil.

“In the Sandveld, we lose minerals if there’s too much water in the soil,” explains Jan. “The cation exchange capacity of our sandy soil is 1 to 1,5. In KwaZulu-Natal it averages 12 to 15 and can be as high as 20, which means KZN’s soil is naturally 20 times more fertile than Sandveld. “But our sandy soil nonetheless has unique properties. When I use biological methods, a large portion of the organic matter going into the soil disappears within two or three years, broken down by micro-organisms.”

Compost

The fertiliser Jan uses has an organic component and he uses compost and manure whenever possible. “I try to get as much organic material as possible so that the compost is created on the land,” he explains. “We supplement this by adding compost tea through the centre pivot. This is made from compost and organic material from plants in natural veld because they have the micro-organisms we need.” Jan expresses his pleasure at earthworms returning to the soil.

“This means we’re doing things right. We don’t usually see earthworms in the Sandveld because there’s hardly any organic matter on the lands we plough, and the soil is dry and hot. But with organic matter lying on the surface, there’s food for earthworms.

“This matter also binds the soil, so the wind no longer blows the topsoil away and there’s no erosion with heavy rain. And yet another advantage is that the organic mulch helps to insulate the soil. This prevents it from getting too cold or too hot, enabling micro-organisms to function better.”

Pesticides

Jan uses the ‘softest’ chemicals on the market: Biostart, Tracer and Green Cure as pesticides; compost extract, fulvic and humic acids and D Press as fungicides. “We use green, light chemicals at only half the quantity we used before. We’re more concerned that the product is the gentlest available and won’t affect our predators, than we are about its price.” 

Cycles on the land

Another aspect of farming biologically is rotating crops in specific cycles. In the first year, Jan plants potatoes and maize to add organic material to the land. He harvests the maize and leaves the residue to serve as mulch. “Then we plant wheat, which benefits from the organic material left over from the maize,” he continues. ”After the wheat, we plant a legume such as lupins, serradella or medics. This diversifies the organic matter that goes into the soil and expands the population of micro-organisms.”

On less fertile soil, he plants serradella and lupins, along with oats and rye, while on the better soil he opts for a mixture of medics, oats and rye. “We use this combination as pasture for Dohne Merino sheep for about three years,” he explains. “The wool and meat cover the costs of planting, and the nitrogen from their dung and urine enriches the soil.”

The pasture crop, planted from the end of March to mid-April, is left as a surface mulch through summer. In the past, Jan grew only potatoes – about 120ha in all. But he realised they were destroying the soil and he was risking bankruptcy this way.

“I reduced the area under potatoes to 40ha, with 40ha of maize, 40ha of wheat and 60ha of grazing pasture in rotation,” he explains. “Potatoes provide the cash flow, and maize and wheat the organic matter as well as income. Grazing gives a diversity of micro-organisms. Sheep dung and urine also provide nitrogen to the soil.”

In late February and early June, Jan plants potatoes that he harvests in July and November respectively. Maize goes in in early October and is harvested at the end of March. Wheat is planted at the end of May and harvested at the end of October or early November. Then the grazing crops are planted and the cycle starts again.

Minimal machinery “First we use a sub-soiler to loosen soil, because sandy soil compacts a lot,” Jan says. He adds, however, that with the soil restored and alive again, he doesn’t think the method will be necessary again. “Then we plant the potato seed, using a modified planter with two discs in front welded together to open the soil instead of ploughing it. At the rear, the wheels close the furrow by rolling over it. The third implement is a ripper to loosen the soil on the compacted tractor tracks.”

Patience required

Jan admits that farming biologically requires five to seven years before results can be seen. “Many things must come together for it to work well. We noticed that we used smaller quantities of chemicals and less water because the organic material on the ground reduced evaporation. We’ve also seen birds, predators and bees return as natural systems are restored.”

Jan is unsure, however, of what his optimal production will be as this is a new way of farming for him. “But I’m sure this is the only way for a farmer in the Sandveld to survive the fluctuating potato price. My production costs are lower than those of other farmers.” He admits that it had taken a “change of mindset” on his part to shift from conventional to biological farming, but after a while needed little convincing. “I saw that nature supported me and old problems disappeared. It was a difficult way to farm at first, but after a few years it became easier.”

Jan’s ultimate goals are abundance and to grow good-tasting potatoes full of nutrients and enzymes. “When other farmers decide to change, they’ll have to walk the same path. Fear may be a big reason for not wanting to change. When potato prices are falling, it seems risky to change methods,” he concludes.