Modeling environmental impact in a semi-arid intensive irrigated watershed

Farida Dechmi, Ahmed Skhiri and Daniel Isidoro

Agricultural Water Management, 2021, vol. 256, issue C

Abstract: Improving on-field farmers’ management skills is imperative for an economically and environmentally sustainable irrigated agriculture in semi-arid areas where the quality of the irrigation return flow (IRF) is mainly affected by excessive fertilization and surplus irrigation water. The SWAT model is used worldwide for environmental impact assessment, however, previous versions were unable to simulate appropriately the hydrological processes in irrigated areas. The objectives of this study were to assess the change preformed in SWAT2018 manual irrigation algorithms and to evaluate the impact of the optimum irrigation and nitrogen management practices on crop yield, irrigation return flows and nitrate load in Del Reguero watershed (Spain) after model calibration and validation. The irrigation algorithm in the SWAT2018 source code did not include the irrigation application efficiency in the net irrigation dose calculation, which is very important in irrigated systems. The streamflow calibration and validation resulting statistics for daily and monthly streamflow indicate a “very good” model performance (NSE = 0.75–0.87). The monthly NO3-N load calibration and validation results indicated ‘‘very good’’ (NSE = 0.83 and PBIAS = 4.7%) and ‘‘satisfactory’ ’to ‘‘very good’’ (NSE = 0.64 and PBIAS = 9.36%) performance, respectively. Scenarios assessment showed that combined recommended N fertilization and optimum irrigation were advantageous both for the environment and farmers’ benefits rather than individual scenarios for reaching maximum reduction in NO3-N loads (52%) with better net incomes for farmers (27% yield increase and 26% less N fertilizers inputs), and irrigation water saving (21%) which leads to savings in energy costs. On the one hand, this study allowed for building a more reliable and suitable SWAT model for use in intensive irrigation watersheds, while on the other hand, it supports and reinforces previous results performed in other pressurized irrigated areas for better farmer acceptance and adoption.

Keywords: Irrigation efficiency; Hydrologic model; Intensive irrigation systems; Irrigation return flows; SWAT; Nitrate (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378377421003917
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:agiwat:v:256:y:2021:i:c:s0378377421003917

DOI: 10.1016/j.agwat.2021.107115

Access Statistics for this article

Agricultural Water Management is currently edited by B.E. Clothier, W. Dierickx, J. Oster and D. Wichelns

More articles in Agricultural Water Management from Elsevier
Bibliographic data for series maintained by Catherine Liu ().