Best Soil for Growing Vegetables and Cash Crops in Nigeria: Simple Guidelines for Successful Cultivation.

Soil composes of:

a) Soil particles

b) Soil water

c) Soil air 

d) Organic matter (humus)

e) Inorganic matter, and

f) Soil organisms (plants and animals).

They are arranged in different spacing, ranging from tiny particles of clay to large particles of gravel and stones. Soil particles are classified according to their sizes as follows:

i. Gravel and stones

ii. Coarse sand

iii. Fine sand

iv. Silt

v. Clay

Soil having a high proportion of sand particles are described as sandy soil or light soils (e.g on the sea shores). This distances between the soil particles are large. This results in better aeration and drainage of soil. The mineral salts are easily leached away by rainfall. Addition of humus improves this type of soil. 

Soils with a high proportion of clay particles are called clay soils or heavy soils. The distances between the soil particles are very small, and water is held strongly in these spaces. When wet, clay soils form very large, heavy and sticky lumps which are different to till. When dry, they form hard clods. A high proportion of water and mineral salts is held by clay soils. Aeration and drainage are very poor in this type of soil. By the addition of substance like lime and humus, clay soils can be made lighter and more useful for plant growth. When lime is added, it acts on the tiny clay particles and tends to aggregate or clump them into larger particles. The latter behave like the larger particles of a light soil. This process is known as "Floccuation" of clay soil.

A soil with an average proportion of all the components and with a good humus content is considered to be ideal for planting and supporting life, and is known as loamy soil or loam. 

So, the best soil-type for plants, crops, vegetables and so on in Nigeria is SANDY-LOAMY soil, not clay. Or loamy soil.