Evaluation of Experimental Plot Design for A SlopIng and Eroding Site

Sloping and eroding soils are often avoided by many agronomists when selecting a site for long term crop or soils research due to concerns about the impact of soil variability on experimental results. The extent of soil loss and erosion phase was determined by comparisons of soil properties at the cultivated site with a forest site having similar soil, slope and landscape characteristics. The cultivated site was dominated by the moderately eroded phase of the Grantsburg soil with approximately 7.5 cm of soil (38% of upper 20 cm of original soil) eroded during the previous 80 years. Prior to the establishment of the tillage treatments of no-tillage (NT); chisel-plow (CP); and moldboard plow (MP), a number of selected soil property parameters were examined to measure the inherent soil conditions that existed within the experimental area, and to test the precision of the experimental design. An experimental design was selected which fit within the field boundaries, landscape position, soil and slope constraints. The experimental design was a Youden Type III, and Incomplete Latin Square, that allowed for randomization of treatments to the plots by both row (block) and column (replication) to control random variability in the two directions. Overall, the experimental design selected to control random variability that existed within the experimental area was effective. This was evidenced by the lack of significant differences among most of the tillage treatment locations with respect to the background data collected.