Soil: appreciate what's beneath your feet

Soil gives life and opportunities. Having land with “good” soil can mean the difference between thriving plants and those struggling to stay alive.

Looking into the soils of sub-Saharan Africa

Much of sub-Saharan Africa has acidic, rusty-red-coloured soil, deficient in organic matter and necessary nutrients for plants such as nitrogen and phosphorus. It is no coincidence then that sub-Saharan Africa has some of the lowest levels of soil fertility and is one of the poorest regions worldwide (Nature).

• Many areas of this region have acidic soils (low pH), meaning it is difficult to grow crops under low-input conditions. In West Africa, some dust from the Sahara is brought by winds and raises the soil’s pH but subsoil acidity remains.
• Also, wind and water erosion is extensive in many parts of Africa with 25 per cent of the land prone to water erosion and 22 per cent to wind erosion (NRCS).
• Soil loss through erosion also intensifies the problem of limited soil depth, a common trait of many of Africa’s soils (NRCS). If digging a hole in these soils, you may quickly reach rock or an impermeable layer.
• Most of the soils in sub-Saharan Africa are deficient in Phosphorus (FAO), a nutrient which is necessary not only for plant growth but also for creating nitrogen.
• Although much of sub-Saharan Africa is made up of infertile soils, more than 90 per cent of Africa’s population lives in this region (WAC)!

Like us, plants need certain nutrients:

Source of information in table from “Plant nutrients in the soil”  (NSW)

Other necessary trace elements include Iron, Manganese, Copper, Zinc, Boron and Molybdenum.

So, what can we do to increase soil health?

Add organic fertilisers

What do burned eggshells, fish by-products, urine, blood meal and manure have in common? All are examples of organic fertilisers.

Fertilisers usually provide the three main macronutrients (Nitrogen, Phosphorus and Potassium) that plants need, in addition to other nutrients mentioned above. Carbon-rich composts and fertilisers improve the organic matter content of soil, which in turn helps support organisms, nutrients and minerals – these components of a soil allow plants to thrive. Organic matter also helps increase the water holding capacity of soil; this is especially important in dry areas and areas where agriculture is dependent on the rain. So, using more organic matter can help a soil retain water!

There are both organic and chemical fertilisers. Organic fertilisers may have an edge on chemical ones because they are slowly released to plants over time. With chemical fertilisers, it is easy to apply too much to soil because the fertiliser is concentrated and very soluble. Another advantage of organic over chemical fertiliser is that organic fertilisers improve water movement and add structure to the soil (OSU).

Some other ways to improve soil health (FAO):

• Use cover crops, usually leguminous crops, to improve soil health by providing permanent soil cover, fixing nitrogen from the atmosphere to the soil, and adding organic matter.

• Integrate livestock with crop production in order to easily apply manure to cropland and therefore receive benefits from nutrients and soil organic matter. Livestock can feed on the crop-by-products.

• Agroforestry, when woody perennials like trees are integrated into farming systems, can have a variety of benefits to soil. Trees have deeper roots than crops and can access nutrients in deeper soil layers. Alley cropping (planting trees or shrubs in rows) can help prevent soil erosion, add organic matter to the system and maintains soil biota to continuously provide crops with nutrients.

SEED Winners have turned this into a business opportunity

Some recent SEED Winners in various sub-Saharan countries have identified ways to enrich soil using waste products as inputs, and have created additional benefits along the way. There are many different inputs you can use to produce organic fertiliser. Let's look at some of the innovative ways SEED Winners produce fertiliser to enrich soil in their communities:

Jardin Green Hope, a 2016 SAG-SEED Winner of Burkina Faso, has trained community members, particularly women groups, to transform an invasive water plant (water hyacinth) into quality fertiliser. Moreover, by removing water hyacinths from bodies of water, they help improve water pollution.

Jardin Green Hope works together with an institution that develops the chemical composition of the fertiliser, and oversees quality management. They also work with another institution that certifies the products and is responsible for the awareness raising campaigns among the farmers and community members on how to collect and treat organic waste, and the benefits of biofertilisers for restoring the health of the local ecosystem. Through this partnership, they have positive social, economic and environmental effects in the local area.

The 2016 SAG-SEED Winner  Safi Organics of Kenya provides organic fertiliser to rural smallholder farmers – these farmers benefit from increased crop yields and income, and their fields benefit through increased soil fertility. The 2015 SEED Winner  Black Gold Farm Manure of Malawi, produces fertiliser from local chicken manure and other organic farm residues. The enterprise also trains farmers on environmental conservation, how to produce the fertiliser, and offers them loans to start fertiliser production.

By turning waste into components of a healthy soil, these SEED winners have helped increase food security locally, provide people with livelihoods and promote sustainable agriculture, in addition to a variety of other side benefits.

Don’t like food? (Still not convinced?) Soil goes beyond providing food for us. Healthy soils are also essential for the natural filtration of drinking water and create a resilient landscape that can withstand impacts of drought or flood.

One of the sectors in the 2017 SWITCH Africa Green - SEED Awards is sustainable agriculture. What innovative idea does your start-up have to produce food in an unpredictable environment, while creating jobs and preserving resources? Apply for the 2017 SAG-SEED Awards before 08 March 2017. 

This article was first published on 19 January 2017 on SEED's blog