The Stars in our Soil: Understanding Soil

Soil is a vital natural resource that supports plant life, sustains ecosystems and plays a crucial role in agriculture. It is a complex mixture of minerals (e.g., Nitrogen, Phosphorus, Potassium), dead and living organisms (e.g., leaves, roots, twigs, bugs), water and air. Soil is essential for life on earth, providing nutrients, water, and support for plants, which in turn support animal life and human activities.

Soils are found on the surface of the earth and serve as a medium for plant growth — from the highest mountains to the deepest valleys. It covers the land and can be found in forests, grasslands, deserts, wetlands, and agricultural fields.

Soil colour varies widely from place to place and can provide clues about its composition and fertility. Common soil colours include brown, which indicates the presence of dead and living organisms; red, often due to iron oxides; yellow, which can indicate the presence of hydrated iron oxides; black, rich in dead and living microorganisms and often found in fertile soils; and gray or white, which may indicate poor drainage or the presence of salts. Very rarely, one may be lucky enough to see blue or green soil in their lifetime!

Soil formation is a slow process that involves the weathering of rocks and the breakdown of organic matter. Plants, animals, and microorganisms contribute to the breakdown of organic matter and the mixing of soil. Time is a crucial factor, as soil formation can take hundreds to thousands of years to form. Soils are essential for plant growth, water storage, and filtration. They provide habitats for organisms, regulate climate by storing carbon, and support construction. Soils also play a crucial role in nutrient cycling and waste decomposition, making them vital for sustaining ecosystems and human life.

Soil has several key properties that determine its suitability for different uses. Take texture as one example of soil properties; soil texture is classified based on the size of its particles. Sandy soil has a coarse texture, good drainage, and low nutrient retention. Silty soil has a fine texture, smooth feel, good water retention, and is fertile. Clay soil has a very fine texture, poor drainage, and high nutrient retention. Loamy soil is a balanced mixture of sand, silt, and clay, making it ideal for farming.

Loamy soil is considered the best for farming due to its balanced texture, good drainage, and high fertility. It provides an optimal environment for root growth and nutrient uptake. Silty soils are also good for farming, especially for crops that require more water. Sandy soils can be improved with organic matter to enhance their fertility. See, there’s something for everyone, regardless of texture!

However, soil properties are not constant; they can change over time due to natural processes and human activities. Factors such as erosion, compaction, and changes in organic matter content can negatively alter soil properties. Agricultural practices, deforestation and urbanization can also impact soil health, leading to nutrient depletion. On the other hand, natural processes and human activities that can positively alter soil properties include; adding compost, green manuring, cover cropping and crop rotation among others. Regular soil testing and applying recommended interventions can correct pH and nutrient deficiencies (we will talk more about this in the next article of this series!). 

While some soil problems can be solved at the farm level, others need to be tackled at extension systems, policy or research levels. Scientists warn that 12 million hectares of agricultural soils are lost globally through soil degradation every year. This implies that now more than ever, we need to take action against soil degradation. Rebuilding healthy soils is a slow process that can take several years to decades to achieve; depending on the extent of degradation and the practices implemented. Adding organic matter and adopting sustainable practices can show improvements within a few years, but fully restoring soil health may take a more robust systems approach and commitment from stakeholders. 

Soil is a dynamic and vital resource that supports life on Earth. Understanding its properties, formation, and the factors that affect its health is crucial for sustainable agriculture and environmental conservation. By adopting practices that protect and rebuild soil, we can ensure its productivity and resilience for future generations. 

To conclude, let’s interact!

Dr. Wole Fatunbe startled a room of young people from Southern Africa who had convened to deliberate on climate action in Lusaka, Zambia from 19th to 21st August by saying “Applying organic fertilizer to increase soil organic matter content does not directly translate to meeting crop nutrient requirements available for plants to uptake, hence, the need for recommended application of synthetic fertilizers.”

Do you agree with Dr. Wole? 

What do you know about your soil?

How do you replenish your soil? 

Has your soil changed over the years? 

Share your thoughts on social media

About the Author

Sussana Phiri is an alumnus of the Global Change Makers School, where she pursued Project Management for Change Makers (2020). She is also an alumnus of the Global Leadership Fellows Programme (GLFP ‘19), which focuses on imparting Strategic Management and Science Communication skills. Her most recent achievement is becoming the Young Professionals in Agriculture Development (YPARD) Zambia country representative.

Sussana carries a wealth of experience in fostering meaningful youth engagements in youth-led projects and women-focused interventions as a developer and project lead of the Future Fields and Orange Fleshed Sweet Potato Projects respectively. She is a certified aquaculture and fish farming professional and holds a certificate in agriculture mechanics and machinery. She possesses a Bachelor’s Degree in Education and is currently studying for a Master of Education in Curriculum Studies from the University of Zambia. Most recently, she acquired a Diploma in Agroecology from the Kasisi Agricultural Training Centre.

Sussana has developed and implemented assignments with partners such as the Zambia Youth Environmental Network, Women Who Farm Africa, Zambia Agriculture Research Institute, Access Agriculture, CAADP Youth Network, Grand Challenges Canada, Chedic Associates, Ministry of Health- Mother and Child Health Department and the Chilanga District Agriculture Department.

Sussana is currently working with CA4SH as a Communications and Coordination intern through CIFOR-ICRAF, and is a member of the #Youth4Soil Initiative. The Stars in Our Soil is a 6-part series highlighting the scientific and social elements of the soil that are synonymous with the stars; each of them unique but when they are together, they light up the universe.