Site-Specific Measurement of Site-Specific Compaction in the Southeastern United States

摘要

Yield variations are common in most fields in the Southeastern U.S. Increasing yields to maximum uniform levels by site-specific measurement and modification of nutrient levels have mostly been unsuccessful. Researchers now recognize that extreme variation in soil physical conditions are much more important than previously thought. Measurement and modification of site-specific soil physical properties are now being attempted. Cone index measurements have been obtained for many soils in the Southeastern U.S. Most of these soils have an impervious soil layer that restricts root growth, particularly during periods of temporary drought that plague the Southeastern U.S., and require annual subsoiling for maximum yields. Measurements of cone index demonstrate the extreme variability in depth to the hardpan layer. Geostatistical models were successfully constructed for this data to predict the approximate distance between sampling points. Results from upland soils showed that more variability may exist in the traffic and no-traffic middles than in the in-row position where tillage may have been extensively used. Similar distances between sampling points were also predicted for coastal plains soils.