Crop water requirements and crop coefficients for jute mallow (Corchorus olitorius L.) using the SIMDualKc model and assessing irrigation strategies for the Syrian Akkar region

Abstract

Jute mallow (Corchorus olitorius L.) is an annual crop grown for human consumption of its nutritious leaves in many regions of the world. Despite its importance for household food security and farmers' income, reliable information on the crop's water requirements is still quite scarce. To overcome this knowledge gap, the irrigation needs of jute mallow grown in the Akkar region in Syria were investigated. The analysis focused on a three-year period (2017)(2018)(2019) where the SIMDualKc model was calibrated and validated for simulating soil water contents and computing the soil water balance in jute mallow plots irrigated with basin and drip methods. The model was further used to determine the probabilities of the demand for irrigation water in scenarios considering different crop season lengths, irrigation methods, and application depths over a longer period of 23 years (1998-2020). The SIMDualKc model was able to simulate soil water contents measured in the field plots, returning root mean square error values lower than 0.001 m 3 m -3 and modeling efficiencies ranging from 0.358 to 0.812. The calibrated basal (non-stressed) crop coefficients (K cb ) were 0.15, 0.95, and 0.95 for the initial (K cb ini ), mid-season (K cb mid ), and end-season (K cb end ) stages, respectively. The crop was harvested twice per season, with the drip treatments presenting the highest water productivity and economic indicators. In contrast, the basin treatment resulted in substantial percolation losses, which affected yields and indicators. Although net irrigation requirements showed a large variation for the extremes of the long-term weather time series, differences between the years representing average water demand and those representing very high water demand were only found for the drip irrigation scenarios. This study contributes to improving irrigation water management of jute mallow in the Syrian Akkar region, and for the sustainability of local production systems.

Water Use and Soil Water Balance of Mediterranean Vineyards under Rainfed and Drip Irrigation Management: Evapotranspiration Partition and Soil Management Modelling for Resource Conservation

“…Issues related to the quality of the measured dataset and the empirical one-dimensional modeling approach used here to describe the soil water balance in a three-dimensional drip irrigation system may also help explaining why the goodness-of-fit indicators are not as high as in former studies, e.g., Paço et al [88]. Nevertheless, the reported goodness-of-fit indicators are within the range of values reported in the literature for soil water content simulations of field crops [89,90], vegetable crops [91,92], and perennial crops [58][59][60][61] using the same model.…”

Searching for Sustainable-Irrigation Issues of Clementine Orchards in the Syrian Akkar Plain: Effects of Irrigation Method and Canopy Size on Crop Coefficients, Transpiration, and Water Use with SIMDualKc Model

“…The soil was Vertisol [56], with the main physical and chemical properties given in Table 2. The sampling details and methodologies used in the determination of soil properties were identical to those reported in Darouich et al [52,53] and can be found in those publications. A subsurface drainage network was buried at depths of 1.25-1.75 m, with drainpipes spacing 15-25 m, to collect excess water.…”

“…The first part of this research study (hereafter referred to as Experiment 1 or E1) was performed from 2007 to 2011, while the second part (Experiment 2 or E2) was developed from 2015 to 2017 (Table 1). Previous studies [52,53] performed in the same research station aimed at estimating the crop coefficients of zucchini squash (Cucurbita pepo L.) and jute mallow (Corchorus olitorius L.) under different irrigation regimes were developed in fields close to the one now used.…”

“…This K c approach is adopted in the SIMDualKc model [45] for computing evapotranspiration fluxes and partitioning ET into crop transpiration and soil evaporation; it has also been successfully applied for a range of crops and environmental and management conditions [46][47][48][49][50]. In Syria, SIMDualKc applications include rain-fed and surface-irrigated wheat in Aleppo [51], and zucchini squash and jute mallow under diverse irrigation regimes in the study area, the Akkar plain [52,53].…”

“…Two experimental data sets were used: one, from 2007 to 2011, where the water use of 10-14 years old citrus trees irrigated with different methods (surface, drip, mini-sprinklers, and bubblers) is compared; the other, from 2015 to 2019, where the water use of the same citrus trees, now 18-20 years old but drip-irrigated, are assessed. Following Darouich et al [52,53], these assessments aim at improving water use in the Akkar plain and the sustainability of local production systems by providing a state-of-the-art tool for irrigation scheduling based on the FAO56 dual K c method. Innovation consists of using a dual K c soil water balance model to compute and compare diverse citrus orchard irrigation methods to accurately determine dual and single K c for clementine as dependent on the canopy cover, tree height, irrigation method, and scheduling, which still are lacking in practice.…”