Effect of Water Stress on the Yield of Selected Vegetable Crops in the Southern Guinea Savannah Ecological Zone of Nigeria.

Abstract

Water stress effect on the yield of tomato (Lycopersicum Esculentum) and onion (AlliumCepa) crops was carried. This study is aimed at understanding the required amount of water needed by onion and tomato plants daily and to predetermine the yield expected from scheduled irrigation under limited water supply. Randomised complete block design experimental layout was employed and replicated five times. The irrigation interval observed was controlled on the first block of regular four days; the second, third and fourth blocks were irrigated six, seven, and nine days respectively. The result of onion showed the highest yield of 31.5 kg/plot (12 t/ha) from the four days regular irrigation interval, followed by six days irrigation interval with a yield of 30.9 kg/plot (11.77 t/ha). The lowest yield of 18.3 kg/plot (6.97 t/ha) was obtained for the nine days irrigation interval. Similarly, the highest yield of 43.1 kg/plot (16 t/ha) in regular four days irrigation interval and the lowest yield of 13.4 kg/plot (5.1 t/plot) for nine days interval was recorded for tomato. The result of this study shows that irrigating at an interval of four to five days has the highest significant yield of 16 t/ha and under critical conditions, the farmer can irrigate seven days as up to 65% - 70% yield was obtained. Irrigation should not be scheduled nine (9) days because about 42% of the yield is lost. It is therefore concluded that the yield water use relationship shows that both onion and tomato crops increases with an increase in the rate of seasonal evapotranspiration provided water application rate does not exceed the required amount at the required amount.