ABSTRACT

The development of a Mini low-cost lysimeter was carried out and the lysimeter evaluated by using it to estimate the consumptive water use of tomatoes (lycopersicon esculentum) in sandy loam soil of Umudike in South Eastern Nigeria.The Mini low cost lysimeter with diameter of 30 cm and depth of 60 cm was constructed fromlocally sourced materials.A cylindrical shape was chosen to achieve the least resistance to flow of water The tomatoes (lycopersicon esculentum)  were established on the lysimeter and  irrigated daily and the daily data generated from the lysimeter were used to calculate the crop evapotranspiration (ETc Lysimeter) for the months of November and December 2017, and January and February 2018. Climatic data obtained for the same period were used to determine the crop evapotranspiration (ETc) using Blaney – Criddle and Thornthwaite methods. The evapotranspiration (ETc) estimates by Blaney – Criddle and Thornthwaite methods were compared with the estimates from the lysimeter. The total crop evapotranspiration for Lysimeter for the four months was 1039.2 mm, while that of Blaney – Criddle and Thornthwaite methods were 871.4 mm, and 276.3 mm, respectively. The margin between the results of the empirical methods and the lysimeter could be as a result of environmental factors prevalent within the experimental site. The result of the statistical analysis carried out on the results obtained from the mean consumptive use show that there is significant different between the lysimeter method and the other two methods  for 5% level of significance at  the growth period of four months.