Soil and Tillage Research
Steinhardt, R., Institute of Soils and Water, ARO, Bet Dagan, Israel
Van der Ploeg, R.R., Institute of Soil Science and Forest Nutrition, Georg-August University, Göttingen, Germany
Ehlers, W., Institute of Agronomy and Plant Breeding, Georg-August University, Göttingen, Germany
Different forms and solutions of the single root model (SRM) arise from: assumed functional relationships between the radius of the SRM soil cylinder and the rooting density (Lr); averaging modes of hydraulic conductivity (K); steady-state or steady-rate flow assumption; and methods of evaluating the root geometry factor (B). SRM forms and solutions, in particular B approximations, were evaluated by analytical comparison and by performance, when incorporated into a water uptake simulation model for oats. The approximation of B as a constant, or as an exponential function of rooting density (B′), had only a small temporary effect on soil water extraction rates and potentials at the soil-root interface. A combination of B′ with exponential rooting profile estimation is proposed as an optimal SRM form for water uptake analysis. It is shown (in appendices) that: (1) assuming SRM steady-state flow to originate on average from the volumetric middle of the SRM soil cylinder is nearly equivalent to the assumption of a steady-rate flow; and (2) utilizing a geometric mean K for the SRM soil cylinder may cause soil water extraction rates to be underestimated. © 1982.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Comparing forms and solutions of the single root soil water extraction model
2
Steinhardt, R., Institute of Soils and Water, ARO, Bet Dagan, Israel
Van der Ploeg, R.R., Institute of Soil Science and Forest Nutrition, Georg-August University, Göttingen, Germany
Ehlers, W., Institute of Agronomy and Plant Breeding, Georg-August University, Göttingen, Germany
Comparing forms and solutions of the single root soil water extraction model
Different forms and solutions of the single root model (SRM) arise from: assumed functional relationships between the radius of the SRM soil cylinder and the rooting density (Lr); averaging modes of hydraulic conductivity (K); steady-state or steady-rate flow assumption; and methods of evaluating the root geometry factor (B). SRM forms and solutions, in particular B approximations, were evaluated by analytical comparison and by performance, when incorporated into a water uptake simulation model for oats. The approximation of B as a constant, or as an exponential function of rooting density (B′), had only a small temporary effect on soil water extraction rates and potentials at the soil-root interface. A combination of B′ with exponential rooting profile estimation is proposed as an optimal SRM form for water uptake analysis. It is shown (in appendices) that: (1) assuming SRM steady-state flow to originate on average from the volumetric middle of the SRM soil cylinder is nearly equivalent to the assumption of a steady-rate flow; and (2) utilizing a geometric mean K for the SRM soil cylinder may cause soil water extraction rates to be underestimated. © 1982.
Scientific Publication