Irrigation suitability evaluation and crop yield An example with Amaranthus cruentus in Southwestern Nigeria

A detailed soil survey of 1.03 hectares of land within University of Ado Ekiti Teaching and Research Farm was carried out to evaluate the suitability of the soils for irrigation agriculture and to examine the influence of three different soil types, water and fertilizer rates on the yield of Amaranthus cruentus. All the soils evaluated were considered not suitable for gravity irrigation but soil A was considered highly suitable, soils B and C were considered moderately suitable for drip irrigation respectively. The results showed that soil types greatly influencedAmaranthus yield significantly (P<0.05). Soil A gave the highest total biomass yield (4597.9 kg/ha), followed by soil C (3152.2 kg/ha) and soil B (3111.1 kg/ha). Fertilizer regime based on soil test gave the highest biomass yield of 4051.6 kg/ha followed by the control with 3636.7 kg/ha and lastly the blanket with 3173.9 kg/ha. The study showed that watering the crop daily gave the highest biomass yield of 3703.1 kg/ha followed by once in two days with 3632 kg/ha and twice daily with 3527 kg/ha. This study confirmed that fertilizer recommendations based on soil test is necessary for determining the adequate level of nutrients that could replenish the soil as well as satisfy the need of the crop. The study suggests the use of drip irrigation rather than gravity irrigation in terms of water use.   Key words: Drip irrigation, gravity irrigation, Amaranthus, suitability evaluation, yield.