Soil is a non-renewable resource and, evidently, arable land is shrinking with increasing global population and urbanisation. This global challenge is further complicated by the changing climate. One would expect these glaring facts to make soil conservation mankind’s top priority, however, the so-called ‘dirt’ is still treated as such. Shrinking arable land resources has led to more intensive cultivation of the land that is available – the horror of modern-day agriculture, which is further characterised by heavy tillage, heavy chemical usage, and less recovery time for soil. Unfortunately, just like most other global challenges, the menace of soil degradation is more pronounced in struggling economies, notably in Africa.
Africa’s soils and the challenges
A notable proportion of Africa’s soils fall within the orders broadly typified as highly weathered (often older soils), highly leached (of nutrients), high in iron and aluminium, and thus are of low natural fertility; or the order typified as weakly developed soils with little profile development (shallow depth), low clay content, and poor water holding capacity to support high crop production.
These challenges have been further compounded by the influx of substandard agricultural chemicals into African countries from Asia, made possible by poor regulatory policies and practices, driven by selfish interests of corrupt officials and governments. Therefore, the interplay of already inherent poor soils, non-existent or poor conservation practices, changing climate, and input of fake agricultural chemicals, has unfortunately exacerbated Africa’s soil challenges, hurting its food security pursuit. The continent is currently faced with naturally- and/or artificially-induced soil salinity, aridity, alkalinity, acidity, compaction, erosion, nutrient depletion, herbicide toxicity, and organism extinction. Unfortunately, some farmers’ ideas of beating these challenges is to abandon their fields and move further into the forested areas in search of better land – a pathway to deforestation.
Beating the challenges
There are realistic, simple, and research-backed approaches to preserving, restoring, and sustaining the productivity of agricultural soils that are still highly underexplored in Africa:
Adopt the fundamentals (and climate-smart practices): Crop rotation, cover cropping, mulching, organic residue introduction, conservation tillage, and contour cropping are all easily adopted practices (which are also elements of climate-smart agriculture) with widely documented research-backed benefits. Benefits collectively include disease and pest control, fertility enhancement, stimulation of microbial activities, erosion control, soil structure improvement, and moisture conservation. The psychological drawback to these practices is often the perception that the benefits are not immediately observed, unlike those of synthetic fertilisers.
Maintain vegetation surface cover: The presence of vegetation cover on soil surface is a sure indication that the soil supports life. Through photosynthesis, plants build and sequester carbonaceous materials which support beneficial soil microbes – critical in nutrient synthesis and cycling. Root penetration and the direct addition of organic matter by surface vegetation further enhances soil structure, porosity, aeration, and water holding capacity.
Implement soil testing: Soil
testing is a vital but rarely adopted practice. The lack of it has led to
frequent over-fertilisation, which is detrimental to soil health and
responsible for environmental degradation and nutrient imbalances in
agroecosystems. Recent discussions on this topic suggest that a relatively
newer soil testing tool – the ion exchange membrane technology
– has comparative advantages (with respect to efficiency, cost, and
convenience), and is potentially the best soil testing tool that can be
deployed in Africa. Sampling locations are easily captured using an app, assisted
by Google maps, and results could also be easily integrated into a programme to make quick and effective
recommendations to farmers.
Embrace organic fertilisers: A study recently published in the Journal for the Advancement of Developing Economies demonstrated that while irrigation and machinery increased productivity in agriculture-based economies, synthetic fertiliser application did not. Organic residue incorporation has been demonstrated to significantly impact the chemical, physical, and biological properties relevant to soils’ recovery, productivity, and sustainability. Organic residues, often treated as wastes, are also cheap.
Improve microbial life: A soil without microbes is a dead soil; soil microbes drive vital soil processes relevant to soil restoration and sustainability. Unfortunately, in Africa, beneficial soil microbes are on the receiving end of the dangers of modern-day agricultural practices, particularly the use and overuse of synthetic fertilisers and pesticides. Thus, the utilisation of biostimulants is paramount. A biotech company, Dynamic Green Concepts, has significantly improved crop yield and soil health in Africa using its proprietary line of biostimulants, which generally work by stimulating the growth of beneficial soil microbes, resulting in increased synthesis and release of tied up nutrients and further stimulating plant growth.
A time for political leadership
In addressing global challenges, government participation is vital. Unfortunately, ‘dirt’ does not yet appear to be the priority of most African leaders. Although most run their campaign platforms on agriculture, it is easier and cheaper to buy the votes and loyalty of the impoverished, under food insecurity.
So, can Africa’s depleted soils sustain the growing demand for food in a time of climate change? The answer is definitely ‘yes’ for the governments that truly see the need for it.