Submitted to: Geocarto International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 15, 1996
Publication Date: N/A
Interpretive Summary: Accurately determining soil properties for such tasks as establishing experimental plots, randomizing experiments, and developing management plans is essential for rangeland researchers and managers. The primary difficulty lies in the variability that exists within very short distances. This study investigated the spatial variation of several rangeland parameters on different slopes. Soil cores were harvested and analyzed for bulk density, particle size, calcium carbonate, and organic matter. High spatial correlations were found for percentage sand, clay, and calcium carbonate on the south-facing slope. Soil bulk density and percentage calcium carbonate in the soil wre the most correlated variables on the north-facing slopes. Eolian influence could have affected the typical soil-landscape ralationships on both slopes. This work showed that spatial variation is high rangelands soils, but can not yet be predicted and used to help develop better management plans.
Technical Abstract: Researchers and managers of semiarid rangelands relly on accurately determining soil properties for such tasks as establinshing experimental plots randomizing experiments, and developing management plans. Spatial variability of many soil characteristics is generally very high often resulting in erroneous assumptions concerning baseline soil properties. A field study was initiated to quantify the degree of spatial variability on a rangeland site in northeastern Colorado. The research site consisted of north- and south-facing slopes. Soil cores were collected at two depths from a 100-point grid laid out on each slope. Soil was analyzed for bulk density, particle size, calcium carbonate, and organic matter. COnventional and geostatistical analyses were conducted to compare variables within and between the two slopes. Spatial correlations were detected for percentage sand, clay, and calcium carbonate on the south- facing slope. Soil bulk density and percentage calcium carbonate in the soil were the most spatially correlated variables on the north-facing slope The general notion that materials are eroded from the summit and deposited at the toeslope was not observed for either the north- or south-facing slopes. The shallow depth of carbonates on the north-facing slope implied long-term soil erosion at the site. Soil carbonates at these sites were distributed in a northwesterly to southeasterly direction on the leeward south-facing slope. Textural differences at the deeper siol layer implied that parent material also influenced soil variability.