Availability of water resources for tomato production in Colombia: a basin modeling approach

In Colombia a large proportion of the country’s population and agricultural activities are concentrated in a few regions, generating a high local demand for water.
To address this demand, this work aims to determine the monthly water availability and water use from two tomato production systems: Open-field (OF) and Greenhouse (GH), operating inside two different catchment basins with biophysical contrasts.
The OF production system operates in the Fonce river basin (6°25’18.83”N, 73°10’03.18”W), while the GH tomato production system operates in the Moniquirá river basin (5°39’37.30”N, 73°34’57.46”W). To estimate the water availability, the Soil and Water Assessment Tool (SWAT) was used.
Required soil and weather-parameter inputs needed for the SWAT model were obtained from geological and meteorological Colombian services, respectively.
The water used by tomato growers were determined by detailed observational follow ups of tomato cropping cycles; 22 for OF, and 39 for GH. Total tomato production areas were estimated by secondary sources, such as satellite images and surveys of plant nurseries to determine plant numbers sold.
Results indicate that water yield was several times higher in OF production systems (1.49 Mm³ km^‑2 year^‑1) as compared to GH systems (0.37 Mm³ km^‑2 year^‑1). Monthly water availability followed the same bimodal distribution as precipitation data.
During the dry season, water availability decreased to 79% (OF) and 96% (GH) compared with the rainy season.
Although, annual tomato areas planted in both areas are similar (OF=320 ha and GH=330 ha), GH tomato system had the highest water use (2.83 Mm³ year^‑1) compared to OF system (0.78 Mm³ year^‑1). In the OF system most of the plantings were synchronized with the first rainy season while for GH production planting date was continuous throughout the year.
The results show that average water use of an average Colombian tomato grower is high (1.01 L plant^‑1 day^‑1) as compared to those in tropical areas where tomato is planted under GH systems (<0.4 L plant^‑1 day^‑1). These large differences suggest a need to evaluate strategies that allow increasing the water use efficiency in OF systems.

XXX International Horticultural Congress IHC2018: International Symposium on Water and Nutrient Relations and Management of Horticultural Crops

R. Gil, A. Guerrero, A.V. Casas-Diaz, C.R. Bojacá, E. Schrevens

irrigation water demand, SWAT model, water yield

https://doi.org/10.17660/ActaHortic.2019.1253.56