Laboratory Methods for Soil Health Analysis, Volume 2. Группа авторов. Читать онлайн. Newlib. NEWLIB.NET

Автор: Группа авторов
Издательство: John Wiley & Sons Limited
Серия:
Жанр произведения: Биология
Год издания: 0
isbn: 9780891189862
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Title Topics addressed Pellant et al. (2020) Interpreting indicators of rangeland health Review of protocols for assessing ecosystem function on rangelands and woodlands. Provides assessment and interpretive guidelines for soil‐associated measurements. Ball et al. (2017) Visual soil evaluation: A summary of some applications and potential developments for agriculture Review of visual soil evaluation methods, with emphasis on the Visual Evaluation of Soil Structure (VESS). Addresses VESS applications to agricultural production and environmental quality. USDA‐NRCS (2001) Soil quality test kit guide Review of assessments made with the Soil Quality Test Kit. Background and interpretive guidelines provided for each assessment. Boone et al. (1999) Soil sampling, preparation, archiving, and quality control Review of protocols for soil sampling and laboratory processing. Guidelines developed for the U.S. Long‐Term Ecological Research Network. Dick et al. (1996) Standardized methods, sampling, and sample pretreatment General guidelines for soil sampling, sample handling, and quality assurance/control. Sarrantonio et al. (1996) On‐farm assessment of soil quality and health Review and application of measurements made by the Soil Quality Test Kit. Results from case studies provided. Petersen and Calvin (1986) Sampling (Methods of soil analysis) Addresses statistical considerations of different sampling approaches.

      In most agroecosystems, inherent spatial soil variation is coupled with management‐induced variation, as reflected by horizontal and/or vertical zones having similar soil properties. Management‐induced variation typically reflects long‐term repeated use of tillage, chemical amendments, controlled traffic (vehicular and animal), irrigation practice, or crop residue removal (Boone et al., 1999). These induced characteristics can often mask inherent variation in soil properties (Wang et al., 2019). Consequently, sources of management‐induced variation must be understood before conducting a soil health assessment. Furthermore, depending upon the evaluator’s goals, it may be necessary to subdivide the sampling area into uniform zones to accurately assess management‐induced variation (Dick et al., 1996).

      All soil properties change over time in response to environmental‐ and management‐related factors. Soil properties strongly influenced by temperature and moisture can fluctuate daily, while those reflecting inherent properties (e.g., texture, mineralogy) change slowly. Though land managers have negligible control over weather and soil forming factors, management decisions, including application of chemical amendments, tillage type and intensity, crop rotation, biomass harvest, and animal activity, can induce significant variation in soil properties (Wuest, 2015; Boone et al., 1999).

      Among the portfolio of soil health indicators, those associated with soil biological activity are influenced by daily and seasonal weather changes and management practices that influence nutrient cycling, carbon balance, and physical conditions (Liebig et al., 2006; Dick et al., 1996). As soil health assessments have evolved to include more biological properties and processes (Bünemann et al., 2017), it is imperative evaluators account for temporal dynamics when collecting samples.

      Sources of Error

Schematic illustration of the flow of the error components associated with soil property assessment.

      Processing error are errors made while collecting, handling, and preparing samples for evaluation (Fig. 2.1). Reducing this error requires consistent application of approved protocols tailored for the specific type of analyses, inclusive of storage conditions. Closely aligned with processing error is measurement error, which arises from an improper application of analytical methods or evaluation techniques. Consistent use of consensus protocols will ensure accuracy and precision of each measurement. For laboratory analyses, use of blanks, internal standards, and reference samples is necessary to detect potential contamination and bias.

      Once data have been collected, interpretation error can further confound errors from site selection, sample processing, and measurement (Fig. 2.1). Interpretation error results from accidental or systematic misinterpretation or improper application of data. Reduction of interpretation error relies on the evaluator’s knowledge to accurately decipher data in context to the sampled site, while concurrently ensuring data outcomes are not extrapolated beyond inherent spatiotemporal constraints or methodological limitations.

      Site Characterization

      Preliminary site characterization is important and encouraged, especially when spatial variation of inherent soil properties and/or previous land use is unknown. If the site is intended for long‐term monitoring, preliminary site characterization is essential. Referencing maps and/or imagery of the site prior to in‐field assessments may elicit attributes not visible from the ground. Preliminary field assessments