Organic Fertilizers for SA Farms

Organic Fertilizers for South African Farms


By Jenny Slabber


Commercial Organic Farming in South Africa is young, but demand for organic produce by health conscious consumers, has resulted in the incredible industry growth worldwide of 35% per year, and faster in South Africa. The challenge was to manufacture Certified Organic fertilizers, which could deliver superior quality organic crops, while maintaining productivity on a sustainable basis.


What are the basic principles of organics?

  • Organic farmers strive to build up a healthy living ecosystem in the soil with beneficial micro-organisms such as bacteria and fungi, which protect plants from diseases
  • Increase carbon content of soil through composting,  green manure and using plant residues as mulch
  • Improve the soil structure, balance and add required nutrient levels to deliver quality plants, animal and human life though quality food.


Inputs like poisons, synthetic fertilizers and herbicides can damage the environment, pollute soil and water sources, kill soil life, or cause toxicity in food, are strictly forbidden in organic farming methods.

When a product, food or process is certified organic, the consumer is assured that a stringent inspection and control system, governed by worldwide standards through IFOAM (International Federation of Organic Agriculture Movements), is applied.


How does organic fertiliser compare with synthetic fertilizer in terms of efficiency and cost?

Direct comparisons are difficult, so an explanation to introduce a few concepts would be useful. In the past organic methods were viewed as low cost inputs (i.e. when animal manures or composts were used as the only source of nutrients) this often resulted in low productivity and organic farming was often not commercially viable. Produce was often stunted, diseased and nutritionally deficient when grown in the naturally poor soils found in many parts of South Africa. Now an alternative range to the synthetic fertilisers is an organic fertiliser range which is scientifically formulated into familiar fertiliser blends like 2:3:2, 5:1:5, 3:1:5. These supply high levels (Group 1) of complete sustained release Nitrogen (N), Phosphate (P) and Potassium (K), with minor and trace nutrients for optimum crop health and commercial production.

Standard synthetic fertilizers supply one, two or three nutrients only, with no minor or trace nutrients (e.g. LAN, Superphosphate or synthetic 2:3:2). This requires regular small applications of fertilizer to crops to ensure sufficient nutrients during their growing and fruiting phases. Then costly top-ups of foliar trace nutrients are applied to prevent deficiencies. These repeated applications increase labour, fuel and machinery costs. Most synthetic fertilizers are water soluble, to make nutrients readily available for plant uptake. This increases the potential loss of nutrient through leaching of up to 50% in sandy soils, which is seldom factored into cost. The bulk of synthetic fertilizers are fillers like lime, gypsum or granite chips, or salt based carriers, so often plant nutrients only make up 10 to 35% of actual weight purchased.

When using natural nutrients from plant, animal and naturally mined sources, these organic fertilizer nutrients are bound in complex forms which are not  water soluble and nutrients are released by microbial action in the soil (fungi, bacteria, algae, plant exudes and soil life) which gives a sustained feed to the crop. No fillers are added. Organic fertilizer should be viewed as an investment as the soil fertility builds up, savings on inputs and therefore costs are reduced.

Many additional factors like sustainability, impact indirectly on eventual cost per ton of fertilizer. South African farmers are being pressured by lifeless unproductive soils, pollution of rivers and escalating costs of pest and disease control, associated with years of overuse of synthetic fertilizers, herbicides and poisons. So many farmers are rethinking and refining commercial practises which could be detrimental to the farms natural production potential and profitability, in tandem with international food safety standards and legislation which is now benchmarked as “no-residue”.   


Can insect pests be controlled as effectively with organic products as with synthetic insecticides?

The organic farmer will be guided by the saying: “Prevention is easier and less costly than cure.” They strive to grow strong and healthy plants, which resist pests and disease with natural immunity. High pest attack is nature’s quality control system removing the weak plant to prevent propagation of a poor specimen. In preference to using poisons, which kill the good with the bad, while potentially adding poison residues to food, the organic farmer uses products that disrupt the pest’s life cycles, comfort, feeding habits, or acts as a repellent. This allows for the preservation of predators and beneficial insects to flourish and contain pest outbreaks naturally. Only as a last resort are natural poisons like Pyrethrum used to regain control of pest attacks. Natural poisons breakdown rapidly, so do not build-up residues in the environment.