Shifts in the Physicochemical Soil Properties Following Land Leveling Practices of a Mississippi River Loess Soil in the Mid-South.

Historically in Louisiana, a majority of row-crop production acres were dry-land systems.   However, with shifting commodity prices much of the region has moved from cotton, a more drought tolerant crop, to more drought susceptible crops, such as corn and soybeans. This has resulted in increased irrigated acres in the Mid-South.  Due to natural topography, most irrigated fields must undergo land leveling as a means to increase irrigation efficiency.  These practices have the potential to drastically influence many soil characteristics, which in turn can potentially influence crop productivity in the future.  Therefore, soil physico-chemical properties were evaluated following the land leveling process.  Significant shifts occurred for most soil physico-chemical properties evaluated.  When comparing between non-altered soil with those influenced from land-leveling practices, significant shifts occurred for soil extractable, Cu, Mg, P, Na, OM  as well as clay percentage, sand percentage, and bulk density.  Furthermore, significant shifts in extractable Ca, Mg, pH, K, S, Zn, OM, as well as all soil particle fractions and bulk density when comparing soils that have been cut versus filled.  This has the potential to indicate extensive redistribution of many soil properties following land leveling.  In addition to shifts in soil properties, the overall spatial variability of these properties shifted as well.  Through spatial autocorrelation, several soil chemical properties (Ca, S, pH, and OM) were found to decrease in spatial variability; however, the majority of these properties (Cu, Mg, P, K, Na, and Zn) were found to increase in the spatial variability.  These results indicate that not only will extensive management be necessary to renew these soils to previous productivity but increased management practices must be carried out to manage with the increased variability of many plant nutrients.