Soil moisture: Rwanda’s most valuable agricultural resource

Every planting season, the conversation begins with seeds and fertilizers. Governments subsidize them, development partners finance them, and farmers invest scarce resources to buy them. Yet one critical agricultural input receives far less attention despite determining whether all these investments succeed or fail. It cannot be manufactured or imported. It is stored beneath our feet after every rainfall, and once it is lost, no amount of fertilizer can fully compensate. That overlooked resource is soil moisture. ALSO READ: Key to preserving Rwanda’s food security lies in the soil By the time a farmer prepares land, buys fertilizers and seeds, and waits for the rains, a significant investment has already been made. Yet one factor ultimately determines whether that investment will pay off: soil moisture. Nutrients may be present in the soil, but crops cannot absorb or use them without sufficient water. Fertilizers alone do not guarantee higher yields. Soil moisture unlocks both naturally occurring and applied nutrients. As Rwanda seeks increased agricultural productivity despite erratic rainfall and rising production costs, we must rethink our most valuable agricultural resource. ALSO READ: Key to preserving Rwanda’s food security lies in the soil Rwanda's agriculture depends overwhelmingly on rain-fed production, yet rainfall is becoming increasingly unpredictable. Dry spells interrupt crop growth, and healthy crops often wither before maturity because rains end too soon. Climate change demands different farming approaches. Although, irrigation is part of Rwanda's agricultural plans it is expensive for most smallholder farmers. While investments in irrigation should continue, the greatest opportunity lies in maximizing available rainfall. Conserving every drop where it falls, inside the soil, is the most practical, affordable, and scalable solution. Permanent Soil Cover, a core principle of Conservation Agriculture, makes this possible. ALSO READ: Rwanda’s practical response to climate change and soil degradation Crop residues or mulch protect the soil surface, reduce erosion, limit evaporation, increase organic matter, and help soil retain moisture after rainfall. The result is healthier soil that supports crops during short dry spells, stimulates biological activity, and improves fertilizer-use efficiency. Improving fertilizer efficiency deserves greater attention especially since fertilizer prices are rising. Governments and farmers invest heavily in fertilizers, yet plants absorb nutrients only after they dissolve in soil water. Conserving soil moisture allows fertilizers to perform as intended and maximizes returns on every kilogram applied. ALSO READ: Why farming startups fail – and how you can avoid it Farmers already understand this principle through experience. In banana plantations covered with residues, soil remains cool and moist during prolonged dry periods. Farmers have mulched banana fields for generations because they observed these benefits firsthand. This practical wisdom can strengthen other cropping systems by improving soil structure, water-holding capacity, nutrient recycling, and rebuilding organic matter. Fertilizers remain essential, but they should not be viewed as the only solution to declining soil fertility. Conservation Agriculture helps farmers use existing nutrients more efficiently while gradually restoring soil health through natural biological processes. It also reduces dependence on costly external inputs by improving the performance of those already applied. Geopolitical conflicts continue disrupting global fertilizer supply chains, affecting prices and availability far beyond Rwanda's borders. Such uncertainty reminds us that resilient farming systems depend not only on producing more but also on using available resources wisely. Fortunately, Rwanda has a strong culture of homegrown innovation. Conservation Agriculture (CA) builds on familiar practices such as mulching banana fields while integrating modern science. By conserving soil moisture, improving soil health, and enhancing fertilizer efficiency, CA strengthens climate resilience and supports sustainable agricultural productivity. As climate variability intensifies, every rainfall event becomes more precious. Rwanda's agricultural future will depend not only on how much fertilizer we apply, but also on how effectively we conserve soil moisture. By maintaining permanent soil cover, farmers can improve fertilizer-use efficiency, strengthen food security, enhance climate resilience, and preserve healthier soils for future generations. In an era of climate uncertainty, conserving soil moisture is among the smartest investments Rwanda can make in increasing future harvests. The writer is the Deputy Vice Chancellor for Applied Research and Extension, Rwanda Institute for Conservation Agriculture (RICA).

Opinions

Soil moisture: Rwanda’s most valuable agricultural resource