Pedotransfer functions for cation exchange capacity, available water holding capacity and soil organic carbon for representative soils of Southern Highland Zone of Tanzania
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Date
2018-10-31
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International Journal of Agriculture and Biological Sciences
Abstract
Pedotransfer functions are useful tools in estimating the not easily measured and expensive soil properties.
They are especially valuable in settings such as the SHZT where limited direct soil measurements are available.
The objective of this study was to develop a series of pedotransfer functions and then evaluate which ones best
estimate cation exchange capacity (CEC), available water holding capacity (AWHC) and soil organic carbon
(SOC). Data from 20 horizons of four representative pedons was used to evaluate the most predictive
properties. Best fit multiple linear regressions were used to obtain relationships and identify property
coefficients. Examples of pedotransfer functions developed for the SHZT are %SOC = 0.1*hue-0.03*value-
0.034chroma (n = 20, r 2 = 0.74), CEC ( meq/100g ) = 0.44*%clay + 9.6%SOC (n=20, r 2 = 0.93), and, AWHC
(mm/m) = 14.7%SOC + 0.82%clay + 0.35%silt + 0.51%sand (n=12; r 2 = 0.96). All color attributes are for
moist samples. The results of predicted CEC, AWHC, and SOC were compared to those measured in the
laboratory using the t-test, and the two methods did not differ significantly; two-sided p-value=0.93. These
results indicate the promising potential of using the easily measured soil properties and cheap in fiscal terms to
estimate the not easily measured soil properties.
Description
International Journal of Agriculture And Biological Sciences, 2018; Sep & Oct 2018: 26-42
Keywords
Pedotransfer function, CEC, AWHC, SOC, Soil Organic Carbon