Evaluation of tomato crop water demand through three evapotranspiration estimation methods in the agro-climatic context of Dschang, Cameroon

The management of irrigation for vegetables, specifically tomatoes, is essential, which involves defining the quantities and frequencies of supply aimed at increasing plant productivity and quality while maximizing water use efficiency. This study evaluated the agronomic performance, irrigation water productivity, and economic profitability of tomato (Solanum lycopersicum L.) cultivated under three evapotranspiration-based irrigation scheduling methods: Penman–Monteith, Blaney–Criddle, and Turc, combined with two irrigation frequencies (daily and every two days) in Dschang, West Cameroon. The experiment was conducted at the University of Dschang's experimental area from November 2021 to March 2022. A split-plot experimental design was used, with methods of ETP determination as the principal factor and frequency as the secondary factor. Tomato growth parameters, yield components, irrigation water use efficiency (IWUE), and economic profitability indicators were assessed throughout the production cycle. Results showed that irrigation dose and frequency had no significant effect on vegetative growth parameters but significantly influenced (p < 0.05) fruit yield, irrigation water productivity, and economic returns (value–cost ratio ≥ 2). The highest marketable yield (81.4 t ha⁻¹) was obtained with the Penman–Monteith method applied every two days, while the greatest irrigation water use efficiency (15.92 kg m⁻³) was achieved with the Blaney–Criddle method applied every two days. All irrigation–fertilization combinations were economically profitable (value–cost ratio ≥ 2), with the Penman–Monteith method applied every two days offering the best compromise between yield maximization and economic return.