21 research outputs found
Water Requirements (Chapter 6)
The main objective of irrigation is to provide plants with sufficient water
to prevent stress that may cause reduced yield or poor quality of harvest
(Haise and Hagan, 1967; Taylor, 1965). The required timing and amount of
applied water is governed by the prevailing climatic conditions, crop and
stage of growth, soil moisture holding capacity, and the extent of root
development as determined by type of crop, stage of growth, and soil
Analysis of evaporative flux data for various climates
Estimation of evapotranspiration is a key requirement of hydrologic
balance studies and climate analysis. The study reported involved collection of
precise weighing lysimeter and meteorological data from three sites representing
distinct climates. The combined data set for daily amounts of evapotranspiration
and meteorological variables covers a total of 19 years on either an annual or
growing season basis. The pan evaporation, Priestley-Taylor, original Penman, and
Penman-Monteith evapotranspiration estimating methods arc compared with lysimeter
measurements using a moving average of 1-30 days. The results indicate
the applicability of the various methods as a function of climate regime and the
reduction in standard error of the estimate and increase in the coefficient of determination
as a function of length of the moving average period. The results can
be used both to determine which methods are most applicable for different climates
and the expected magnitude of the error as a function of the estimating interval.
This study indicates that a 5-10-day moving average can reduce the standard error
of the estimate and increase the coefficient of determination significantly between
estimated and measured reference evapotranspiration for several estimating methods
for various climates
Water Requirements (Chapter 6)
The main objective of irrigation is to provide plants with sufficient water
to prevent stress that may cause reduced yield or poor quality of harvest
(Haise and Hagan, 1967; Taylor, 1965). The required timing and amount of
applied water is governed by the prevailing climatic conditions, crop and
stage of growth, soil moisture holding capacity, and the extent of root
development as determined by type of crop, stage of growth, and soil