ISHS Acta Horticulturae 278: Symposium on Scheduling of Irrigation for Vegetable Crops under Field Condition
WATER DEMAND OF CARROTS AS AFFECTED BY THE NUTRIENT, SALINITY AND AERATION STATUS OF THE SOIL |
| Authors: | U. Schmidhalter, J.J. Oertli |
| Abstract:
The water requirement of carrots as affected by salinity, nutrient supply and soil aeration was investigated in a groundwater-influenced silty soil under field and growth chamber conditions. The predominant factor controlling the evapotranspiration coefficient (amount of water used/unit biomass produced) was the nutrient level of the soil. Soil salinity and soil aeration had a lesser impact with respect to the evapotranspiration coefficient. Under optimum conditions and favourable nutrient supply, evapotranspiration coefficients amounted to 300–400 L kg-1 storage root dry weight (RDW). The evapotranspiration coefficients remained unchanged up to salt concentrations of 16 mS/cm in the soil solution. At higher salt concentrations, the evapotranspiration coefficients increased to 600–700 L kg-1 RDW. Low nutrient levels increased the evapotranspiration coefficients to values significantly higher than 1000 L kg-1 RDW. Evapotranspiration efficiency, the reciprocal value of the evapotranspiration coefficient, was strongly decreased by low nutrient levels associated with increased salinity and/or insufficient soil aeration. Evapotranspiration coefficients were essentially constant at high yield levels. | |
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