Soil Health, Land Management and Remediation of Sodicity.

Soil sodicity can degrade soil health. Land management strategies for sodic soil remediation can include perennial grassland systems, subsurface tile-drained annual row crop production, and/or soil amendments.  The objective of this study was to develop a minimum data set to assess soil health and its spatial variability in a sodic soil previously cropped to perennial hay and converted to tile-drained annual row crops. Baseline soil samples were taken to a 30-cm depth in a hay field before and after tillage, but prior to planting of the row crop in a field divided into 45, 24 x 24 m blocks. A suite of soil biological (percent carbon and soil enzyme assays: ammonia oxidase, nitrate reductase, urease, β-glucosidase, arylsulfatase, alkaline phosphatase, and fluorescein diacetate hydrolysis), chemical (electrical conductivity, pH, sodium adsorption ratio), and physical (texture) properties were reduced to a minimum data set for an Exline soil (fine, smectitic, frigid Leptic Natrudolls) in Richland County, North Dakota, USA. Spatial autocorrelation of the sample points was addressed using Moran’s I statistic and samples were found to be randomly distributed. Principal component analysis was performed separately for each land use to determine the minimum set of soil variables that could account for 75% of the total variation. Highly weighted variables for each principal component axis were further reduced by choosing the variable(s) with the greatest spearman correlation coefficient score sums. Enzyme assays were sensitive indicators of edaphic properties, reflecting biological activity and cycling of plant available nutrients. Our research will provide a set of soil quality indicators to assess the effects of management on soil health and the spatial distribution of dynamic soil properties in a sodic Exline series and potentially other similar sodic soil series.