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An Algorithm for Calculating the Least Limiting Water Range of Soils
Author(s) -
Leao Tairone Paiva,
Silva Alvaro Pires,
Perfect Ed,
Tormena Cassio Antonio
Publication year - 2005
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2004.0229
Subject(s) - subroutine , soil water , limiting , range (aeronautics) , soil science , statistical analysis , algorithm , computer science , environmental science , statistics , mathematics , engineering , mechanical engineering , aerospace engineering , operating system
The least limiting water range (LLWR) is used to estimate the optimum soil water content for plant growth based on the range of bulk density values for a given soil series under evaluation. However, the use of this methodological approach by soil scientists has been limited by the lack of a detailed description of the statistical and mathematical procedures used for its calculation. This paper describes a Statistical Analysis System (SAS) algorithm for calculation of the LLWR from bulk density, volumetric water content, water potential, and soil penetration resistance data. Since nonlinear regression techniques are used, a brief description of the theory involved in this type of statistical analysis is presented. To improve the visualization and interpretation of the LLWR results, a plotting subroutine is also described. Five soils with different textures and management conditions were used to validate the algorithm. Statistical comparison with previously published LLWR calculations showed that the new method is reliable and accurate and can substantially reduce the time and labor necessary to estimate the LLWR of soils.