Effects of varying levels and frequencies of irrigation on growth,yield, nutrient uptake and water use efficiency of maize and cowpeas on a sandy loam ultisol

Summary A greenhouse study was carried out on an Nsukka sandy loam Ultisol having low soil moisture retention capacity to investigate the soil moisture regime and irrigation frequency required for optimum growth, yield, nutrient uptake and water use efficiency of maize (Zea mays L.) and cowpeas (Vigna unguiculata L. Walp). Four irrigation amounts (400 cm³, 300 cm³, 200 cm³ and 100 cm³ equivalent to 100, 75, 50 and 25% of field capacity, respectively) and four irrigation frequencies (daily, 2-day, 3-day and 4-day intervals) were tested in a factorial randomized design with three replications.Growth of maize was best when irrigation with water equivalent to 75% field capacity at daily interval but the optimum yields and nutrient uptake of both crops as well as cowpea nodulation were obtained when irrigating with water equivalent to 100% field capacity at daily or 2-day interval. The optimum water use efficiency was, however, achieved when irragating with amount equivalent to 100% field capacity at a 2-day interval. Irrigation with water equivalent to 50 or 25% field capacity at any interval resulted in various degrees of moisture stress which manifested in poor crop performance.