Contribution to irrigation from shallow water table under field conditions

The mathematical model SWBACROS was applied to estimate the contribution of a shallow groundwater to the water needs of a maize crop. The model was applied with the top and boundary conditions defined by the observed irrigation/rainfall events and the observed water table depth. The simulated water contents of the top zone were very close to the observed values. Furthermore the model was applied with an assumed free drainage bottom boundary condition. The difference of the computed water content profiles under the presence and absence of the water table gave a very good estimate of the capillary rise. It was found that under the specific field conditions about 3.6 mm/day of the water in the root zone originated from the shallow water table, which amounts to about 18% of the water, which was transpired by the maize crop.

[1]  J. Ayars,et al.  Use of Saline Water from a Shallow Water Table by Cotton , 1986 .

[2]  K. Gallo,et al.  Prediction of Daily Green Leaf Area Index for Corn1 , 1980 .

[3]  G. J. Hoffman,et al.  Use of saline drainage water for irrigation: Imperial Valley study , 1989 .

[4]  K. H. Hartge,et al.  Feddes, R. A., Kowalik, P. I. und Zaradny, H.: simulation of field water use and crop yield. Pudoc (Centre for agricultural publishing and documentation) Wageningen, Niederlande, 195 Seiten, 13 Abbildungen, Paperback. Preis: hfl 30,– , 1980 .

[5]  J. E. Ayars,et al.  The resource potential of in-situ shallow ground water use in irrigated agriculture: a review , 2006, Irrigation Science.

[6]  Christos Babajimopoulos,et al.  A Douglas‐Jones Predictor‐Corrector Program for Simulating One‐Dimensional Unsaturated Flow in Soil , 1991 .

[7]  R. Feddes,et al.  Simulation of field water use and crop yield , 1978 .

[8]  Van Genuchten,et al.  A closed-form equation for predicting the hydraulic conductivity of unsaturated soils , 1980 .

[9]  P. J. Wierenga,et al.  Evaporative Flux from Irrigated Cotton as Related to Leaf Area Index, Soil Water, and Evaporative Demand1 , 1978 .

[10]  Asad Sarwar Qureshi,et al.  Modelling the Effects of Deficit Irrigation on Soil Salinity, Depth to Water Table and Transpiration in Semi-arid Zones with Monsoonal Rains , 1999 .

[11]  Zia-ul-Haq,et al.  Effect of shallow groundwater table on crop water requirements and crop yields , 2005 .

[12]  J. Doorenbos,et al.  Guidelines for predicting crop water requirements , 1977 .

[13]  Reinder A. Feddes,et al.  Simulation model of the water balance of a cropped soil: SWATRE , 1983 .

[14]  James E. Ayars,et al.  Characterizing ground water use by safflower using weighing lysimeters , 2003 .

[15]  J. Ayars,et al.  Long term use of saline water for irrigation , 1993, Irrigation Science.

[16]  Christos Babajimopoulos,et al.  SWBACROS: A model for the estimation of the water balance of a cropped soil , 1995 .

[17]  Christos Babajimopoulos,et al.  Revisiting the Douglas-Jones method for modelling unsaturated flow in a cultivated soil , 2000, Environ. Model. Softw..

[18]  W. Wallender,et al.  Estimating the Contribution of a Perched Water Table to the Seasonal Evapotranspiration of Cotton1 , 1979 .