Irrigation and Drainage最新文献

Amidst climate change and recurring droughts, increasing irrigation water amount and frequency alone is not a definitive solution to address water scarcity in agricultural crop production, particularly in soils with poor water retention capacity. This study evaluated the effects of two drought adaptation strategies (deficit irrigation and soil amendment) based on data from a pot experiment. The results indicated that the combined use of a soil amendment product with deficit irrigation enhanced the water use efficiency (WUE). Deficit irrigation starting in the midstage combined with the soil amendment product achieved higher water use efficiency (0.24 and 0.32 g/L for spring and winter wheat, respectively). This is considered to be an optimum WUE, as it was attained with a reduced actual evapotranspiration of 3.78 L for spring wheat. In contrast, with full irrigation, a higher WUE of 0.40 g/L was achieved but with approximately double the actual evapotranspiration of 6.10 L. Additionally, the drought coping of wheat was manifested by the stage-wise adjustment of its crop coefficient. In general, the influence of deficit irrigation on the crop coefficient adjustment was more pronounced than the effect of soil amendment was.

ENORASIS has been developed as a real-time smart irrigation decision support and management system consisting of weather forecasting systems based on satellite observations, irrigation optimization techniques and wireless sensor networks. This study revealed that irrigation could be managed with ENORASIS without a significant decrease in efficiency when less water is used (14%–71%) than with the conventional irrigation management approach. Thus, fewer agricultural chemicals are washed away from the soil, but water efficiency increases, leading to the use of less water and groundwater pollution. According to these results, although ENORASIS usually stands out as a recommended irrigation management system in terms of water usage parameters and performance indicators for both cotton and maize, either of the two irrigation management systems could be preferred considering yield, technological and agronomic characteristics. Among these, the choice should be made according to the results of an economic analysis on factors such as time, labour and energy needs for water supply, as well as metered irrigation and pricing in water and irrigation costs. This study revealed that ENORASIS can be used for sustainable irrigation and water resource management.

Clogging represents a critical challenge that undermines the efficiency and sustainability of drip irrigation systems by inducing uneven water distribution and increasing maintenance requirements. In this study, the phenomenon of clogging in drip emitters was investigated via computational fluid dynamics (CFD) in conjunction with the discrete element method (DEM). The original drip (OD) was analysed to pinpoint areas prone to particle accumulation, particularly in regions characterised by low velocity and reduced turbulence kinetic energy, conditions that facilitate particle deposition. The analyses revealed that vortex formation in narrow corners and stagnation zones within the emitter’s flow path primarily contributed to clogging. To address this issue, a modified drip (MD) was proposed, aimed at optimising flow patterns and mitigating vortex development. CFD–DEM simulations of the MD indicated a significant reduction in clogging risk and enhanced particle transport efficiency. At an inlet water velocity of 0.075 ms⁻¹, the MD achieved a 2% higher particle transport rate than did the OD, and similar improvements were noted at higher velocities. These findings underscore the potential of design modifications to enhance system performance and reduce maintenance costs. Future research should further validate the MD under diverse environmental conditions, including variable water qualities and different soil types.

Irrigation water supply is under scrutiny because of dwindling water resources. Most irrigation water in South Africa (SA) is transmitted by canals. Transmission water loss (TWL) accounts for 12% of the irrigation water losses in SA. Therefore, there is a need to investigate and understand the major parameters influencing TWL at Vaalharts Irrigation Scheme (VIS). A study using 39 concrete-lined canal reaches was performed from 2020 to 2022. Water flow measurements and observations of selected environmental parameters with potential influence on TWL were performed on three occasions during the study. The velocity-area method was used to calculate flow rates at the canal reach inlets and outlets. The inflow–outflow approach was used to determine TWL (% per 100 m). The study results revealed that TWL increased significantly (p < 0.05) with decreasing canal size. Canal shape and location had no significant effects on TWL; however, the TWL decreased in the middle zones. Flow-related parameters strongly affected TWL. Environmental parameters also exhibited strong effects. Although the study results elucidate TWL at VIS, further research involving more intense data collection is recommended. The effects of non-physical parameters should also be investigated in future studies. Maintenance should be prioritized in irrigation schemes that use canals.

Résumé

Le suivi des tendances de la consommation d'eau dans le secteur agricole (en tant que principal consommateur de ressources en eau disponibles), compte tenu notamment des effets du changement climatique, est l'une des exigences les plus essentielles pour la planification à long terme des ressources en eau. Cette étude vise à évaluer les effets du changement climatique sur la consommation d'eau des cultures agricoles dans le bassin versant de Marun, situé au sud-ouest de l'Iran. À cette fin, des scénarios climatiques de température et de précipitation ont été produits selon des scénarios représentatifs de trajectoire de concentration (profils représentatifs de concentration) (RCP2.6, RCP4.5 and RCP8.5) tirés du cinquième rapport du Groupe d'experts intergouvernemental sur l'évolution du climat (GIEC) pour l'intervalle futur (2016–2040). Ensuite, en recueillant des données météorologiques de la région et en utilisant des scénarios de température et de précipitations comme entrées dans le modèle Cropwat, les changements dans l'eau nécessaire pour le secteur agricole ont été calculés. Les résultats de Cropwat montrent que la demande totale en eau du secteur agricole selon les scénarios RCP2.6, RCP4.5, et RCP8.5 augmentera de 38%, 39%, et 40%, respectivement, dans la période future (2016–2040) par rapport à la référence. Il est essentiel de comprendre les effets exercés par les changements de température et de précipitations sur les besoins en eau et en irrigation des cultures pour que les décideurs élaborent des politiques à long terme plus précises et plus réalistes concernant les ressources en eau et l'approvisionnement en produits agricoles, en particulier dans le contexte du changement climatique.