Framing Smallholder Fertilizer Practices as Nature-Based Solutions: Evidence from Semi-Arid Sunflower Systems in Tanzania

Abstract

Sunflower production supports smallholder livelihoods in semi-arid Tanzania, yet soil fertility constraints limit productivity. This study examined farmers’ fertilizer practices in Bahi and Mpwapwa districts through a Nature-Based Solutions (NbS) lens, focusing on awareness, perceived effectiveness, alignment with integrated soil fertility management, and factors associated with recommended use. Data were collected from 361 farmers using structured questionnaires and focus group discussions. Awareness of fertilizer use was higher among farmers with more education and longer farming experience, while trained farmers reported more favourable perceptions of fertilizer performance. Respondents in both districts commonly associated fertilizer use with faster crop growth, improved plant condition, and higher yield, although these outcomes were self-reported rather than independently measured. DAP and urea were the dominant fertilizers, while NPK use was lower. Focus group discussions showed that many farmers combined mineral fertilizers with manure, crop residues, and moisture-conserving practices, indicating partial alignment with NbS principles related to nutrient cycling and soil stewardship. The study contributes to NbS scholarship by illustrating how farmer knowledge systems mediate the ecological alignment of nutrient management strategies in semi-arid smallholder agriculture. These findings suggest that strengthening extension support, soil advisory services, and context-specific fertilizer recommendations may enhance alignment with NbS principles while supporting resilient sunflower production systems.