Probability Sampling Techniques for Estimating Soil Erosion

Abstract

Data on the lateral variability of soil loss from Submediterranean rangelands are presented. Modified Gerlach troughs were used to measure both rill and interrill erosion. Random, systematic, stratified random, and cluster sampling methods were tested for various numbers of plots and plot widths in order to find the method that gives the most accurate estimate of soil loss. If both the rill and interrill subpopulations are sampled, random sampling and stratified random sampling give almost identical standard errors. Cluster sampling yields larger errors and is therefore less effective. Systematic sampling, however, allows one to choose more accurate samples of an economical size, but its efficacy depends largely on the number of rills in the study area. The smallest standard errors are obtained by measuring the total rill erosion and by sampling only the interrill subpopulation. When this procedure is applied, the four sampling methods turn out to be equally accurate.

The dynamics of soil redistribution and the implications for soil organic carbon accounting in agricultural south‐eastern Australia

“…Soil erosion measurement and monitoring approaches, particularly in semi‐arid environments, require sufficiently long (ca, 15 years) and expensive campaigns to provide representative and reliable estimates of soil erosion (Roels, ). Even with such campaigns the extrapolation of their results from often small experimental plots to large areas is notoriously unreliable and unrealistic across nations because of considerable spatial and temporal variation in the sediment delivery (Roels & Jonker, ).…”

Modelling soil losses from the ardeche rangelands

“…Sixty troughs were installed on each slope segment; they were arranged 'en echelon' to ensure a clear run to each trough from the crest (see Fig. 2 and also ROELS & JONKER 1983). On the upper slope segment interrill erosion was measured in 54 troughs, pre-rill erosion in 5 troughs and rill erosion in 1, while on the lower slope segment 48 troughs caught interrill erosion, 7 caught pre-rill erosion and 5 rill erosion.…”

“…Interrill erosion results both from detachment by raindrop impact and from detachment by shallow concentrated flow intensified by drop impact. Neither interrill nor pre-rill erosion bring about a relatively uniform removal of soil (ROELS & JONKER 1983). The aim of this paper is to present a first attempt at modelling interrill, pre-rill and rill erosion on a field or hillslope scale for individual storm events.…”

Australian net (1950s–1990) soil organic carbon erosion: implications for CO<sub>2</sub> emission and land–atmosphere modelling

“…15 years) and expensive campaigns to provide representative and reliable estimates of erosion rates (Roels, 1985). Even with such campaigns, the extrapolation of results from experimental plots and field studies to large areas is notoriously unreliable and unrealistic at the catchment scale and larger because of considerable spatial and temporal variation in sediment delivery (Roels and Jonker, 1983). The caesium-137 ( 137 Cs) technique overcomes most of the difficulties with long-term erosion monitoring programmes because it provides retrospective information on medium-term (ca.…”