Modified square root of time relation to predict evaporation trends from bare soil

Abstract

The existing methods of calculating cumulative evaporation (CE) from water transport theory pose a problem of availability of the governing parameters of the soil and atmospheric evaporativity. An empirical relation between CE, inclusive of the constant rate stage, and its time limit is not available. We investigated relations between CE and time (t) for different evaporativities (4). Estimates of CE by using the empirical relations between CE, t and vt agreed well with the observed values: where tf is the duration of the constant rate stage which can be computed from K and E0 K is the r,egression coefficient of CE on vt and b is the intercept. The results indicated that the duration of the constant rate stage decreased with increasing E0 and increasing redistribution time (T); CE under a lower E0 can exceed that under higher E0. Evaporation rate during the falling rate stage is dependent upon E0. For the same E0, the duration of the constant rate stage was higher in silt loam than in sandy loam.