The importance of healthy, productive soils to grow for Namibia
“Soil – building a productive, food secure Namibia from the ground up” is a critical approach in the agronomic sector in Namibia and follows on the 68th United Nations General Assembly Declaration of 2015 as the International Year of Soils. The declaration is implemented by the Food and Agricultural Organisation (FAO) worldwide and its mandate is related to fostering food security in countries all over the world. The strategic point of focus for the FAO is that soils are a strategic resource because it constitutes the foundation for healthy and sustainable food production for the planet. Directly and indirectly, 95% of our food comes from soils. Fertile soil is thus the true origin for nutritious food and the roots of good farming practice. Soil is a non-renewable resource that needs – and deserves – good care, protection and good management if producers are to depend on it for quality crops and high yields.
“The International Year of Soils” highlights many of the aspects of soil management and soil conservation and how all these aspects translate into food sustainability and food security all over the world. According to literature produced by the FAO to publicise 2015 as the International Year of Soils, a healthy soil is defined as the capacity of soil to act as a living system.
The Namibian Agronomic Board invited the FAO to address local producers on the International Year of Soils theme. Liesl Wiese, a consultant for the FAO did a presentation to Namibian producers on the importance of improving and maintaining soil health. In her presentation to over 150 producers from all over the country, Wiese acknowledged that Namibian producers are challenged with sandy soils and shared insights into just how sandy soils can be productive if they are managed well. She started by explaining on a micro level, how healthy soils lock in nutrients and minerals that are needed for high yielding and nutritious crop outputs.
To improve soils and promote nutrient availability for plant uptake, building up organic matter in soils is crucial. Organic matter gives soil a sponge-like structure and fluffy texture because of the humate coating that is introduced to it that binds soil particles together. The humate coating of the soil particles gives soil a negative charge, enabling it to hold onto the positively charged soil nutrients. The gridlock structure that results from this binding of soil and nutrients also holds onto water for longer and slows down the movement of water through the soil profile. This means that nutrients are not lost to leaching, but locked into place in magnet-like fashion by the negatively charged soil particles and the positively charged nutrients. These nutrients are then bio-available to plants and taken up through its root hairs and root system, ensuring a healthy, nutrient rich plant and crop.
Adding organic compost to soils is a sure way of maintaining the health of soils and continuing to produce healthy crops. Eliminating chemical and artificial inputs when fertilising soils ensures the “living system” definition of the FAO, a system where microorganisms coexist and live in symbioses with nutrients and essential gases in soils. Chemical inputs destroy that natural balance of living soil systems and interrupts, for example, a soil’s natural ability to absorb much needed carbon from the atmosphere. This simple action from a healthy soil system helps to mitigate climate change, a crucial by-product of sustainable food production.
Managing the effects of sun exposure to crops ensures the longevity of healthy soils. This is achieved by mulching, an easy process that minimises the evaporation of water in the topsoil and also minimises the disturbance of soils. Wiese introduced many ways of mulching; using newspaper, cardboard, wood chips and leaves. The exposed soil surface is merely covered with these which allows water to remain in the soil and more available for uptake by the plants.
Effective irrigation systems in crop production were also introduced as an element of healthy soils. The aspect is particularly relevant for drought-prone countries like Namibia. Drip irrigation delivers water to exactly where it is needed at a rate that is determined by the producer who will judge how much water is required. Implementing the practice of mulching, along with increasing the water holding capacity of soils, is important for Namibian producers because of the uncertainty of reliable rainfall and the longevity of water sources for irrigated crops in our country.
Wiese told producers, “If you take care of your soils and implement these processes, even the sandy soils that you have to work with, can be extremely productive.”
Although soil plays important function for human well-beings, unsustainable food production practices that regard soils merely as an input-output system or medium, are degrading our precious soil resources. Already, more than a quarter of our planet’s soils are facing degradation as a result of soil erosion, soil sealing, soil contamination and salinisation, loss of organic carbon and the depletion of vital nutrients. This negative view – and use – of soil needs to be reversed because according to the FAO, the planet will need to increase its food production by 60% by the year 2050 to feed the population. Soils on the African continent also face this problem and approximately 16% of its soils are compromised by degradation. It is estimated that effective and sustainable soil management implementation can increase food production by 58% over the long term by restoring degraded soils and building soil health in currently productive soils.
Sheila Storey, the owner of Nemlab, a nematode diagnostic laboratory in South Africa, addressed Namibian producers on how to spot the tell-tale signs of nematodes present in soil. Because they thrive in sandy soils, nematodes pose a significant threat to Namibian horticulture production. Storey demonstrated with various case studies how different crops are affected by different strains of nematodes. After having dedicated nearly 30 years to researching nematodes, Storey has in-depth knowledge of nematode diagnostics, problems relating to nematodes and has until recently, taken on a holistic approach when making recommendations to producers.
In recent years, Storey’s interest has turned to preserving soil health when dealing with nematodes and she shared the principles of biofumigation with brassica crops as an alternative method of control. Brassica crops such as cabbage, broccoli, cauliflower and kale produce sulphur that when it decomposes and combines with other enzymes in soils, causes a fumigation effect in soil borne pathogens, such as nematodes.
As the importance of the agricultural sector has developed over the years, so too has the importance of formalising qualifications in the agricultural sector at vocational training level by developing skilled and successful commercial farmers. Dr Peter Lenhardt of the National Training Authority informed producers of what has already been achieved in the Republic of Namibia regarding vocational training, where practical and relevant skills for the Namibian horticulture sector will be imparted to willing trainees.
Francois Wahl of Agra spoke on the importance of taking soils samples and its packaging for sending to the laboratory for analysis, as well as how the results should be interpreted. He also gave a practical demonstration of how soil samples should be gathered and packaged for laboratory analysis.
Producers found the presentations enlightening and interacted with presenters. Producers took these learnings to heart to implement at their farms. Shetuuka Shetuuka, winner of the Horticulture Producer of the Year in the Emerging Scale category has started implementing the optimal supply of water to his crops of butternut and tomatoes. He has also started mulching with grass. “Although it is a lot of work, I started mulching which is very good because the grass protects the upper layer of the soil around my butternuts and tomatoes and the grass decomposes and adds value to the soil as well,” he said.
Building healthy soils in the Republic of Namibia to result in a food secure nation will take the combined efforts of all producers and starts with promoting the sustainable management of soils in order to increase production and offer more nutritious crops. Innovative approaches will be required that support the establishment and maintenance of healthy soils that supply essential nutrients, water, oxygen and root support that food producing plants need to grow and thrive – all with sustainable farming practices that limit harmful inputs that degrade soil health.
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