Design and Assessment of a Capillary Irrigation System for Fertilizer MICRO-Dosing in Vegetable Production.

The study tested an innovative scalable capillary irrigation system for production of leafy Amaranthus viridis in humid forest and savanna agro-ecological zones of southwestern Nigeria. The irrigation system consists of a PVC pipe reservoir that discharges water directly to the plant rooting zone in response to evapotranspiration demand. We compared the capillary irrigation system with a sprinkler system under different modes of fertilizer application in a field study arranged in randomized complete block designed with four replicates in the two study locations. The capillary irrigation innovation produced higher fresh vegetable yield compared to all other treatments. Water required to produce one kg of fresh amaranth increased by a magnitude of three in the savanna ecosystem compared to the forest. We found the capillary irrigation system to significantly reduced the volume of water required to produce fresh leafy amaranth with the difference being more pronounced in the savanna ecosystem. The yield and water use differences in spot and banding fertilizer application were not significant. Meanwhile the capillary irrigation system saved an average of 1.1 million liters and 6 million liters of water per ha in the savanna and forest locations respectively per growing season.