Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Evaluation of point-scale assessments of soil quality
Abstract
Point-scale assessments of soil quality occur over a range of approaches, from highly analytical to broadly descriptive. Identification of approaches to on-farm evaluation of soil quality for different agricultural clients requires knowledge of benefits and drawbacks of different assessment approaches. This study was conducted to evaluate four different assessment approaches: farmers' perceptions, field-descriptive, field-analytical, and laboratory-analytical assessments. Twenty-four conventional and organic farmers throughout eastern Nebraska were paired within regions of similar climate and topography, and perceptions of soil quality indicators on their 'Good' and 'Problem' soils were queried using a written questionnaire. Field-descriptive, field-analytical, and laboratory-analytical assessments were conducted on each soil. Results from farmers' perceptions, field-descriptive, and field-analytical assessments were then compared to laboratory-analytical results. Overall, perception accuracy of soil quality indicators did not differ between conventional and organic farmers. Farmers' perceptions of soil quality indicators tended to be more accurate for 'Good' soils as compared to 'Problem' soils. Indicators that were incorrectly estimated at a frequency greater than 33% included available nitrogen and phosphorus, soil color, degree of compaction, and infiltration rate. Despite this, farmers' perceptions were correct or nearly-correct over 75% of the time for the majority of indicators evaluated in the study. Field-descriptive assessments of topsoil depth and soil texture were accurate or near-accurate in at least 92% of the cases, whereas assessments of compaction and available water-holding capacity were less accurate due to difficulty in relating descriptive qualifiers to quantitative values. Results from field-analytical assessments of electrical conductivity, soil pH, and soil nitrate accurately matched laboratory-analytical results in at least 46% of the cases despite differences in sampling depth for field and laboratory evaluations. Assuming changes in sensory qualifiers for field-descriptive assessments and sampling depth for field-analytical assessments, point-scale assessments can be most effective by beginning with the use of farmers' knowledge of soil and progressing toward assessments that require increasingly more time, resources, and technical expertise.
Subject Area
Soil sciences|Agronomy
Recommended Citation
Liebig, Mark Anthony, "Evaluation of point-scale assessments of soil quality" (1998). ETD collection for University of Nebraska-Lincoln. AAI9826092.
https://digitalcommons.unl.edu/dissertations/AAI9826092