Sorghum Yield Using Rectangular Versus Spherical zaï Pits and Integrated Soil Fertility Management in the Sahelian and Sudano-Sahelian Zones of Burkina Faso

Poor farming practices have contributed to the degradation of the majority of soils in Burkina Faso. This has led to the formation of bare soils and new clearings. These soils are generally reclaimed by zaï, an ancestral water and soil conservation practice that needs further improvement to ensure food security. The following study consisted of giving a rectangular shape to the usually spherical zaï pits in order to measure sorghum yield’s parameters in a factorial design: type of amendments (compost + NPK and compost + urea + Burkina phosphate); length (35 and 45 cm) and depth of the pits (10 and 20 cm) with 4 replications. Using the sites of Kiembara (Sahelian zone) and Arbollé (Southern Sudan-Sahelian zone), sorghum growth, biomass, grain yield, harvest index and threshing rate were measured. Overall, highlight the importance of rainwater harvesting using zaï pits and the use of manure in combination with mineral fertilizer supplements in improving soil fertility and enhancing crop yields. There is good evidence that grain yield was significantly improved under rectangular zaï with 45-cm-long pits (2032.7 kg.ha⁻¹ in Kiembara, 1561.7 kg.ha⁻¹ in Arbollé) than under ordinary zaï (1053.6 kg.ha⁻¹ in Kiembara; 990.2 kg.ha⁻¹ at Arbollé). This yield improved further with the application of compost combined with Burkina phosphate and urea under the rectangular zaï of 45-cm-long and 20-cm deep pits, 2333.9 kg.ha⁻¹ in Kiembara and 1967.7 kg.ha⁻¹ in Arbollé. Under ordinary zaï, the same inputs resulted in a grain yield of around 1034.5 kg.ha⁻¹ in Kiembara and 916 kg.ha⁻¹ in Arbollé. Hence, rectangular zaï was better than ordinary zaï in increasing the agronomic parameters of sorghum, especially in the Sahelian agroclimatic zone, providing good water conditions to produce enough useful cobs and therefore a solution to reduce food insecurity.