Effect of Groundwater Level Depth and Irrigation Amount on Water Fluxes at the Groundwater Table and Water Use of Wheat

Abstract

Three irrigation water regimes (90.0, 67.5, and 45.0 mm) and five groundwater table depths (1.5, 2.0, 2.5, 3.0, and 3.5 m) were considered in a lysimeter experiment to investigate the effect of groundwater level and irrigation amount on water fluxes at the groundwater table and water use of wheat. Results show that deep percolation (irrigation of 16-23%) occurred to a considerable extent in the present irrigation level at a shallow groundwater table of 1.5-2.0 m. Capillary rise comprised 29% of the water use of wheat, within the period from regreening to harvest, at 1.5 m groundwater table depth, and was reduced with an increase in table depth. A relationship between groundwater contribution and groundwater table depth was also found. In the present irrigation conditions, the water productivity (WP b ) of wheat was enhanced from 3.59 kg m -3 at a shallower groundwater level depth of 1.5 m, to 4.58 kg m -3 at a deeper groundwater level depth of 3.5 m. WP b can be higher if deficit irrigation is enforced and can reach 3.93-6.03 kg m -3 . Similarly, a relationship between WP b and groundwater table depth was found. Hence, the irrigation amount per time for local wheat can be reduced to 45.0-67.5 mm, depending on the groundwater level depth, in order to use water resources effectively. RÉSUMÉTrois régimes d'irrigation (90.0, 67.5 et 45.0 mm) et cinq profondeurs de la nappe phréatique (1.5, 2.0, 2.5, 3.0 et 3.5 m) ont été considérés dans une expérience en lysimètre pour étudier l'effet du niveau de la nappe souterraine et la quantité d'eau d'irrigation sur les flux vers la nappe et les prélèvements d'une culture de blé. Les résultats montrent que la percolation profonde (irrigation de 16-23 %) est considérable pour le niveau d'irrigation actuel pour une nappe phréatique peu profonde de 1.5 à 2.0 m. La remontée capillaire représente 29% de la consommation du blé entre le stade de reverdissement et la récolte pour une profondeur de nappe à 1.5 m, et elle réduit si la profondeur de la nappe augmente. Une relation entre la contribution des eaux souterraines et la profondeur de la nappe d'eau a également été trouvée. Dans les conditions d'irrigation actuelle, la productivité de l'eau (WP b ) de blé est augmentée de 3.59 kg m -3 pour une nappe à 1.5 m à 4.58 kg m -3 pour une nappe plus profonde à 3.5 m. WP b peut être plus élevé si l'irrigation déficitaire est appliquée et peut passer de 3.93 à 6.03 kg m -3 . De même, une relation entre WP b et la profondeur de la nappe phréatique a été trouvée. Par conséquent, la lame d'eau par tour d'irrigation pour une utilisation efficace de l'eau peut être réduite à 45.0 à 67.5 mm, selon le niveau de profondeur des eaux souterraines.

Effects of the shallow water table on water use of winter wheat and ecosystem health: Implications for unlocking the potential of groundwater in the Fergana Valley (Central Asia)

“…Using the Meyer equation (Wu et al, 1999), Ayars et al (2006) found that the maximum upward fluxes occur when the root zone is dry and groundwater table is shallow and the minimum upward fluxes occur when the root zone is wet, with either deep or shallow groundwater. Huo et al (2011) came to similar conclusions based on their lysimeter studies of the water use of wheat.…”

“…The quantification of upward fluxes from a shallow groundwater table is a significant topic that has been extensively researched (Ganiev, 1979;Zhang et al, 1999;Soppe and Ayars, 2003;Kahlown et al, 2005;Babajimopoulos et al, 2007;Yang et al, 2007;Huo et al, 2011). In the Fergana Valley, Ganiev (1979) studied over a period of four years the capillary rise from a shallow water table in lysimeter experiments under fallow and natural conditions, and cropped with cotton or alfalfa.…”

“…The results showed that, under rainfed conditions, the seasonal contribution of groundwater met more than 65% of potential evapotranspiration of winter wheat when the water table depth was within 40-150 cm. Huo et al (2011) studied the effect of the groundwater level and irrigation amounts on the water use of wheat in a lysimeter experiment at the Hongmen experimental station located in the Henan Province, China. Capillary rise supplied 29% of the water use of wheat during the time period from ripening to harvest when the groundwater table was 1.5 m deep, and was reduced when the depth of the groundwater table decreased.…”

Impact of capillary rise and recirculation on crop yields

“…The importance of capillary rise as supplier of water to crops has been shown by many researchers (e.g. Huo et al, 2012;Talebnejad, and 90 Sepaskhah, 2015;Han et al, 2015); however we found only a few studies that use an integrated modelling approach (Xu et al, 2013;Zipper et al 2015) to quantify capillary rise for different hydrological conditions (including free drainage) using physically based approaches. In this study we explicitly consider the effect of crop type, soil type, weather year and drainage condition on capillary rise.…”

Assessing the Effect of Different Water Table Depths on Water Use, Yield and Water Productivity of the Okra Crop

“…al. [14] found that the wheat crop consumed 29% of its water demand from subsurface waters when the WTD is maintained at 1.5 m. They also observed that the contribution of subsurface irrigation helps in lowering down the WT. Ayars et.…”