Talent Namatsheve's research shows how conservation agriculture and biochar can affect crop productivity, soil fertility and emissions of greenhouse gases in low-input tropical systems, offering practical solutions for smallholder farmers in sub-Saharan Africa.
In her doctoral thesis, Talent Namatsheve explored how climate-smart agricultural practices, specifically conservation agriculture and biochar, impact productivity and nitrogen cycling in low-input tropical cropping systems. Her research, conducted in sub-Saharan Africa, reveals promising results for smallholder farmers.
Key Findings:
Namatsheve's meta-analysis showed that biochar significantly boosts biological nitrogen fixation and grain yield. Combination of different principles of conservation agriculture also increased grain yield; and specifically, residue retention increased soil nitrate and nitrous oxide (N2O) emissions. This highlights the need to balance crop yield improvements with environmental considerations.
Field studies in unfertilized cropping systems in Uganda confirmed that biochar amendments in conservation agriculture systems, using pigeon pea-maize rotations, enhance productivity and biological nitrogen fixation without affecting N2O emissions. This approach offers subsistence farmers a viable strategy to intensify pigeon pea production and improve soil fertility over time.
Applying biochar in smaller doses over several years yields similar results to a one-time high dosage, making it accessible for resource-constrained farmers. While cumulative N2O emissions were low, biochar and conservation agriculture did not significantly affect these emissions, likely due to the tight nitrogen cycle in unfertilized tropical soils.
Implications:
Namatsheve's research underscores the potential of conservation agriculture and biochar amendments to enhance soil fertility, biological nitrogen fixation and crop yields without increasing greenhouse gas emissions. This is crucial for improving food security and environmental sustainability in sub-Saharan Africa.
Her findings contribute to the growing body of knowledge on climate-smart agriculture and support informed recommendations for smallholder farming in tropical regions. By demonstrating the benefits of these practices, her work helps build resilient cropping systems in the face of climate change.