Root Water Uptake

Plant roots play a very important role in the connection between evaporative demand at the leaf surfaces and plant available soil water. The dynamic root growth of agricultural crops is particularly influential as the new roots penetrate new soil mass and water source. Established plants such as perennial grass also continually grow new roots, but in a less dramatic seasonal pattern.

The solution of root water abstraction are not highly sensitive to the rooting description partially because of compensation by soil water redistribution. If root uptake is overestimated for a specific layer, that layer becomes dryer than expected but water moves from moisture layers to the dry layer, thus a compensation of processes. The root water density distribution does not include the effects of soil water availability. Any water uptake reductions due to soil drying are estimated by the crop water stress relationship.

While the "typical" root pattern of a given plant provides a good approximation by the entered distribution, modifications due to moisture gradients, dense soil layers or high water tables should be considered. A procedure to adjust the entered distribution to represent root modifications when soil water profiles stop growth in dry layers and cause proliferation in wet layers are not included, although it would be a realistic addition.

Field Hydrologic Processes | Precipitation | Infiltration | Potential ET
Interception | Soil Water Evaporation | Plant Transpiration | Crop Water Stress
ActualET | Soil Water Redistribution | Irrigation