Recovery of soil health crucial for agricultural sustainability

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This is according to Johan Habig, senior researcher in microbiology at Microlife Research Centre. “Soil life plays a crucially important role in soil health due to the wide range of functions fulfilled by various organisms,” he explains. “These functions include the release, that is, the mineralisation and circulation of micro- and macro-elements from the organic material and root exudates, production of plants’ growth hormones, organic acids and even toxins that could keep disease-causing bacteria, fungi and nematodes away from plant roots.”

Promoting soil health

Habig points out that the imbalance could be exacerbated by increased application of chemical fertilisation, resulting in soil life not being able to fulfil its functions optimally, to the detriment of the plant and general soil health.

"When we as people 'rest', we don’t do it without food and clothing. Similarly, agricultural land merely lying fallow does not promote soil health," he says. "The most beneficial way to let soil ‘rest’, is to either keep a layer of organic material on the surface or to plant a cover crop. This will keep the soil life nourished and prepared for the next growing season."

Further benefits of permanent soil cover include the regulation of soil temperature, prevention of water loss and even the reduction of soil erosion.

Preventing total dependence on chemical agents

According to Habig, there could be various reasons why producers do not apply these practices, including high costs or even a lack of correct information.

He warns that the most detrimental biological result of inadequate attention to soil health is plants’ and crops’ total dependence on chemical fertilisation and other chemical agents to survive. “Should this happen, increasing quantities of chemical fertilisation will have to be applied to ensure the same yields,” he says.

There are also secondary functions that are compromised by a decrease in soil health, amongst other things, aggregate stability, the penetration capacity of water and the suppression of soil-borne diseases.

"Soil health deals with the chemical, physical and biological interactive processes and features of soil that are important for sustainable production. Laeveld Agrochem and its partners support the attempts of producers to improve their soil health and, accordingly, we make the technology available to take the necessary measurements of these interactive processes and features.

"Our purpose is to assist farmers to ensure sustainable production and, ultimately, to make nutritious food available to consumers," says Phillip Venter, marketing manager of plant nutrition at Laeveld Agrochem.

A decrease in nutritional value

There is no record of the biological facet of soil health in South Africa, but Willem Eigenhuis, chief agronomist of grain and pecan nuts at Agri Technovation, says international research indicates that the mineral content of the food that we take in, particularly fruits and vegetables, have decreased dramatically. “Data from the past 50 years indicates that the mineral content of food such as fruits and vegetables have decreased by between 20% and 50%,” says Eigenhuis.

"It is alarming because it means that we are cultivating volumes of food without the necessary nutritional value, which could also be a reason for the growing incidence of obesity; people taking in large quantities of food depleted of essential minerals and nutritional value."

Damage caused to the natural environment

A WWF South Africa report, titled Agri-Food Systems: Facts and Futures, which was released earlier this year, points out that the way in which we put food on our tables could cause more damage to the natural environment than any other human enterprise. "Existing practices could lead to a loss in biodiversity, deforestation, poorer soil health, desertification, water scarcity and poorer water quality and also contribute to widespread damage to our marine ecosystem," the report states.

"This unfair and environmentally unfriendly food system means that South Africa will have to produce 50% more by the year 2050 to feed the local population, which is estimated to reach 73 million by that time."

Eigenhuis points out that the focus should not be exclusively on greater production, but also the cultivation of more nutritious food.

"Corrective agricultural processes could help to produce food with improved mineral content on fewer hectares, which is critically important for South Africa as a water scarce country with only 13% arable agricultural land. More nutritious food will hold the additional benefit of consumers having to take in less to obtain the same, or the necessary nutritional value," he concludes.