By Umar Nsubuga
In the heart of Uganda’s lush agricultural landscape, the secret to bountiful harvests lies just beneath the surface.
While good seeds and weather play a role, agronomists Gideon Zakke and Henry Sekyewa insist that the real magic starts with the soil.
With years of experience, they’re on a mission to help farmers understand what makes soil thrive and how small changes can yield big results.
From pH levels to organic matter, these experts break down everything a gardener needs to know to unlock the full potential of their land.
“A farmer’s soil is as important as the seed itself,” says Zakke.
“Good soil is rich in nutrients, well-drained, and structured in a way that supports root development,” he adds.
According to Zakke, ideal gardening soil consists of a balanced mix of sand, silt, and clay, known as loam. Loam has a structure that allows it to hold adequate water while draining efficiently, creating a favorable environment for plant roots.
Sekyewa adds that soil pH is another critical factor for gardeners to consider.
“Most plants thrive in soil that has a pH level between 6 and 7, which is slightly acidic to neutral. This pH range allows for optimal nutrient availability,” he explains.
A pH level outside this range can limit nutrient absorption, leading to stunted growth or poor crop quality.
Sekyewa emphasises the importance of testing soil pH before planting and recommends that farmers consult local agricultural extension officers or use simple pH test kits to determine the acidity or alkalinity of their soil.
Soil testing is a practice both agronomists strongly advocate.
“Testing your soil before planting is like getting a health check-up before starting a race,” says Zakke.
A basic soil test can reveal its nutrient content, pH level, and even the presence of contaminants, which are crucial for determining how well plants will grow.
“In Uganda, farmers often overlook soil testing due to lack of access or information, yet it’s a simple and effective way to understand what the soil needs.”
Testing helps farmers determine if they need to add specific nutrients or amendments.
Sekyewa advises farmers to test their soil at least once every two years and before beginning a new planting season.
“Soil can be depleted over time, so knowing what nutrients are lacking enables farmers to add targeted fertilizers or organic matter.”
In addition to testing, both agronomists stress the importance of organic matter in soil health. “Organic matter is what gives soil its life,” says Sekyewa.
By adding compost, manure, or plant residues, farmers can increase the soil’s fertility, water retention, and ability to support beneficial microorganisms.
Organic matter acts like a sponge, holding water while providing essential nutrients like nitrogen, phosphorus, and potassium, which plants require to grow.
Zakke explains that adding organic materials is particularly beneficial for sandy soils, which tend to drain quickly and lack nutrients. Clay soils, on the other hand, are often too dense and can retain too much water, leading to root rot. Adding organic matter helps improve both types of soil, making sandy soils more fertile and clay soils more porous.
The importance of soil drainage
One of the most overlooked aspects of soil quality is drainage.
“Roots need oxygen as much as they need water,” says Sekyewa.
Without proper drainage, excess water can suffocate roots, leading to plant diseases and reduced crop yields. For gardeners with heavy clay soil, which holds water too well, the agronomists recommend incorporating sand or organic matter to enhance drainage. In contrast, sandy soils that drain too quickly may need more organic material to improve water retention.
Farmers are encouraged to conduct a simple drainage test. Dig a hole about one foot deep and fill it with water, letting it drain completely. Then, refill it and time how long it takes for the water to drain.
“If it drains within one to two hours, the drainage is good. If it takes longer, consider amending the soil,” explains Zakke.
Choosing the right soil amendments
The right soil amendments can help address various issues with garden soil, and Sekyewa provides specific recommendations for different soil types.
For acidic soils, he suggests adding lime to raise the pH, while sulfur can help reduce pH in alkaline soils.
For nutrient-deficient soils, balanced fertilizers, especially those containing nitrogen, phosphorus, and potassium, are essential. Organic options such as bone meal, fish emulsion, and seaweed extract can also boost soil fertility without the environmental impact of synthetic fertilizers.
