Evaluating Subsurface Clay Pot Irrigation: Water Use Efficiency and Crop Yield in School-Managed Vegetable Gardens, Dodoma Region

{ "background": "Water scarcity severely limits small-scale vegetable production in semi-arid regions, threatening nutrition and agricultural education. Conventional surface irrigation methods, often used in school gardens, are highly inefficient, leading to low yields and discouraging student participation.", "purpose and objectives": "This intervention study assessed the efficacy of subsurface clay pot (olla) irrigation in improving water use efficiency (WUE) and crop yield in school-managed vegetable gardens, compared to traditional hand-watering basins.", "methodology": "A matched-pair, on-farm trial was implemented across 12 primary schools. Schools were randomly assigned to either the clay pot intervention or the control (basin irrigation) for cultivating amaranth and tomatoes. WUE (kg/m³) and yield (kg/m²) were the primary outcomes. Data were analysed using a linear mixed-effects model: Yij = \β0 + \β1 Xij + uj + \εij, where uⱼ represents school-level random effects, with robust standard errors.", "findings": "Clay pot irrigation significantly increased mean WUE by 65% (95% CI: 48%, 82%) and marketable yield by 42% for amaranth. Tomato yield showed a positive but non-significant trend. Qualitative feedback highlighted reduced labour burden for student gardening clubs.", "conclusion": "Subsurface clay pot irrigation is a highly effective, low-cost technology for enhancing water productivity in school-based agricultural projects in water-stressed environments.", "recommendations": "Integrate clay pot irrigation training into primary school agriculture curricula. Extension services should promote this technology for homestead gardens, particularly where child labour is involved in watering.", "key words": "water use efficiency, appropriate technology, school gardening, sub-surface irrigation, semi-arid agriculture, on-farm trial", "contribution statement": "This study provides the first empirical evidence from a controlled field trial on the agronomic and labour-saving benefits of clay