Field‐scale modeling to explore salinity problems in irrigated agriculture1

Abstract

One-third of irrigated land is affected by salinity or is expected to become so in the near future. A rapid assessment to evaluate the effect of changes in the quality and quantity of irrigation water was tested for the Rudasht irrigation project in Iran. This was performed by using a physically based, well-tested simulation model for crop growth, water and salt transport at field scale. Data used were from an existing dataset and missing data were obtained by converting data from the available set to the required ones. Results indicate that the current practice of 900 mm annual application rates for cotton, given the current salinity level of 4 dS m − 1 , is close to the optimal one. Graphs are presented to evaluate the effect of different combinations of application rates and salinity levels on yields, and the water and salt balances. It was concluded that the methodology presented here is versatile, rapid, and transferable to other conditions. Moreover, the method produces output at a high spatial and temporal resolution over a long time frame. On arrive à démontrer que la méthodologie mise en oeuvre ici est souple, rapide et transférable à d'autres conditions. Par ailleurs, la méthode produit des résultats avec une résolution spatiale et temporelle élevée sur un horizon de temps long.

Sustainable use of groundwater for irrigation: a numerical analysis of the subsoil water fluxes

“…Feddes et al, 1988). SWAP has previously been applied and validated for the irrigation conditions in Pakistan, Iran and India (Bastiaanssen et al, 1996;Van Dam and Feddes, 1996;Smets et al, 1997;Beekma et al, 1997, Sarwar et al, 2000Droogers et al, 2001). In the present study, particular emphasis is given to changes of the vertical soil water fluxes with depth.…”

An easily implemented agro-hydrological procedure with dynamic root simulation for water transfer in the crop–soil system: Validation and application

“…Since models of this type are simple and the algorithms are easy to implement without numerical difficulties, many agro-hydrological models have employed this approach for soil water simulation (Arnold et al, 1993;Ritchie, 1998;Greenwood, 2001;Droogers et al, 2001;Brisson et al, 2003;Rahn et al, 2007;Renaud et al, 2008). Such models include the prominent CropWat model developed by the FAO which was widely used for irrigation scheduling (http://www.fao.org/nr/water/infores_databases_cropwat.html).…”

Yield of beet cultivars under fertigation management and salinity control in a protected environment

“…Among the problems caused by excess salts in the soil, a reduction in the total potential of water in the soil stands out, as well as toxic effects of specific ions on the metabolic processes of plants. Together, these processes can compromise yields and the quality of production (Droogers et al, 2001).…”