Water Use Efficiency of Taro (Colocasia Esculenta) Under Varying Watering Regimes and Planting Densities in Embu, Kenya

Published  September  2023


Tropical and Subtropical Agroecosystems 26 (2023): #075

Joyce Wambui Njuguna1*, Anne N. Karuma1 , and Patrick Gicheru2


Background. Taro (Colocasia esculenta) can be grown in a variety of environmental and edaphic conditions, but it is most typically grown in wetlands. The optimal conditions for its growth are two water regimes i.e., waterlogged or flooded conditions to dryland or unflooded conditions. An important criterion in crop yield is water use efficiency (WUE), and it has been suggested that crop production per unit of water used can be increased. Objectives. To determine the WUE of taro in Kenya’s sub-humid environment under different watering regimes and planting densities. Methodology. A study was conducted at the Kenya Agricultural and Livestock Research Organization (KALRO) – Embu Research Centre, during the long rains (LR) 2021, short rains (SR) 2021/2022, and long rains (LR) 2022. A factorial experiment with a split-plot layout arranged in a completely randomized block design was used. The main factor was the irrigation levels while the sub-factor was the planting density, with three replications. The three irrigation levels were at 100 %, 60 %, and 30 % based on the field capacity (FC). The planting densities used were 0.5m × 0.5m (40,000 plants ha-1 ), 1m × 0.5m (20,000 plants ha-1 ), and 1m × 1m (10,000 plants ha-1 ), representative of high, medium, and low planting densities respectively. Results. The WUE was influenced by season and watering regime (P < 0.05). The 30% FC had the highest WUE with the 100 % FC having the lowest. The high WUE under 30 % FC (19.40 kg ha - 1mm-1 ) was associated with the high biomass (1.97 kg) and low water use (2269.41 mm) recorded under limited water conditions. The medium (1m × 0.5m) planting density attained the highest WUE (12.16 kg ha-1mm-1 ) with the high planting density (0.5m × 0.5m) having the lowest (10.65 kg ha-1mm-1 ), though no significant differences were recorded. Implications. The varying watering regimes and planting densities in this study have different capacities to utilize the supplied water. The total taro biomass increased with decrease in water supplied and in turn maximized the water use efficiency. Conclusion. To achieve the highest yield per unit of water consumed, a watering regime of 30 % FC and a planting density of 1 m × 0.5 m (20,000 plants ha-1 ) is recommended. Key words: water use efficiency; irrigation; planting density; yields.