Profitability Analysis of Zai Pits Use in Cowpea (Vigna unguiculata (L.) Walp) Production under Normal watering and Drought Stress Conditions

The zai system is a traditional agricultural practice used for crops production for water and nutrients management. A study was conducted in Burkina Faso at Kamboinsin to evaluate the profitability of the zai use in cowpea cultivation. Treatments consisted of three levels of drought stress (control, drought stress at seedling and flowering stages), three zai levels (control (tillage); 15 and 25 cm zai depth) and the variety at four levels (Gorom local, Moussa local, KVx396-4-5-2D, Tiligre). The experimental design was a split-split-plot replicated three times. Grain yield and economic data were recorded and cost and returns analysis performed. 25 cm zai depth recorded the highest total variable cost and the control the least. In control conditions, the highest grain yield and net revenue were recorded in 25 cm zai depth for 50% of the varieties and in 15 cm zai depth for the others. In seedling and flowering stages drought stress conditions, the highest net revenue was recorded in 25 cm zai depth, while the lowest was recorded in the control (tillage). The highest benefit-cost ratio was consistently registered in the control (tillage) for drought-tolerant varieties. For drought-sensitive varieties, higher benefit-cost ratio was registered in zai pits in seedling-stage drought stress conditions. The use of manual zai substantial increases cowpea grain yield, but does not consistently guarantee a high economic profit. The mechanical construction of zai could reduce the cost of pits implementation and increase the financial profitability.