Simulation of water transport in the soil-plant-atmosphere system
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The Department of Agronomy seeks to teach the study of the farm-field, its crops, and its science and management. It originally consisted of three sub-departments to do this: Soils, Farm-Crops, and Agricultural Engineering (which became its own department in 1907). Today, the department teaches crop sciences and breeding, soil sciences, meteorology, agroecology, and biotechnology.
History
The Department of Agronomy was formed in 1902. From 1917 to 1935 it was known as the Department of Farm Crops and Soils.
Dates of Existence
1902–present
Historical Names
- Department of Farm Crops and Soils (1917–1935)
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- College of Agriculture and Life Sciences (parent college)
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Abstract
The objective of this dissertation is to develop a mechanistic model of water transport in the soil-plant-atmosphere system that describes the plant's physical expression of water stress to study the effects of environmental factors, and plant hydraulic and physical properties on plant water transport;The model includes soil moisture uptake, soil heat and water transfer, evapotranspiration, and energy partitioning in the canopy and at the soil surface. The model inputs are: daily weather data (air temperature, dew point temperature, wind speed, and solar radiation); initial soil moisture and temperature profiles; plant characteristics; root density; and soil hydraulic properties. The model user may select from a number of outputs. Principal outputs include: leaf resistance, leaf temperature, soil moisture profile and evapotranspiration rate;The model describes a feedback mechanism by which transpiration controls leaf water potential, leaf water potential influences leaf resistance, and leaf resistance which, in turn, controls transpiration;The simulation runs represented the energy partitioning in the canopy and at the soil surface, and the diurnal variation of temperatures and vapor pressures of the leaf, the canopy air, and the soil surface. The relationships of leaf water potential to soil water potential, leaf resistance and transpiration were also presented. In addition, results show that root water extraction is related to the root length density profile and the soil moisture profile;The model mechanistically describes the water transport in the soil-plant-atmosphere system. The results of model validation indicated that the model is capable of simulating plant water transport under natural conditions with reasonable accuracy. Results show that the model simulates the basic features of the system including feedback processes. The sensitivity studies show that the model may be used to study plant water response to environmental factors and plant properties. The model is also useful for estimating evapotranspiration and the soil moisture profile and may provide information for irrigation and soil water management. (Abstract shortened with permission of author.)