Which of the following environmental, physiological, and soil factors govern the rate of consumptive use (evapotranspiration) of an irrigated field crop?
Options:
(A) Vapor pressure deficit ($e_s - e_a$) of the atmosphere and incoming net solar radiation
(B) Canopy stomatal resistance and Leaf Area Index (LAI)
(C) Available soil moisture tension and osmotic potential in the root zone
(D) Magnetic declination of the geographic meridian
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
- Statements A, B, and C are primary drivers of crop evapotranspiration:
1. Atmospheric evaporative demand (net radiation, temperature, wind, vapor deficit).
2. Plant physiological control (stomatal aperture, aerodynamic roughness, leaf area).
3. Soil moisture status (water availability, hydraulic conductivity, salinity osmotic stress).
- Statement D is geomagnetic and has zero influence on fluid dynamics or transpiration.