Proceedings of the 2023 Mississippi Water Resources Conference

Year: 2023 Authors: Witthaus L., Pawlowski E., Locke M., Stevens E., Chatterjee A.

Colloquially, Mississippi Delta soils are known to be high in phosphorus. While soil phosphorus levels do not reach those of the Upper Midwest or areas applying animal manure, Delta soils retain a high level of phosphorus without continual application. However, there are limited publications conveying soil and sediment nutrient levels in this region. Understanding baseline soil nutrient levels, as well as nutrient dynamics, can improve simulations of nutrient transport in models and provide valuable information for watershed water quality management. This presentation will showcase results from a study evaluating properties of soils in both agricultural and forested areas within four different soil series common in the MS Delta: Dundee, Forestdale, Alligator, and Sharkey. We found that Mehlich-3 phosphorus (P) levels were similar across Alligator, Dundee and Sharkey soils in both land uses, but they differed in Forestdale soils. Soils in forested areas exhibited higher total carbon (C), and nitrogen (N) concentrations (p<0.01) compared to soils in cropped areas. Mehlich-3 iron had a positive correlation with Mehlich-3 P in three of the soil series in cropland, but the relationship was negative for natural soils. A suite of other variables was measured and relationships between these characteristics will be explored in this presentation. In addition, we will demonstrate potential uses for such a database through a modeling example.