From Wetland to Beef Cattle Pasture then to Wetland and Beyond: Impact on Soil Nutrient Dynamics and Environment.

Many wetlands were lost in the coastal plain region of Southwest Florida, primarily as a result of drainage for agricultural activities because of the passage of the Swamp Land Act of 1849. Wetland drainage could be analogous to subject wetlands to an extreme and long term drought. There is an earnest need to understand the historical condition and chemical/biological functions of the ecosystems following a conversion of wetlands to agricultural functions. To better understand the soil nutrient dynamics during wetland conversion to beef cattle pastures and beyond restoration of biogeochemical processes cycling after wetland reconversion, soil core samples were collected from the converted beef cattle pastures and from the natural wetland at Plant City, FL in summer of 2002, 2003 and 2006. Compared with the adjoining natural wetlands, the beef cattle pasture soils, 65 years after being drained exhibited: (1) a decrease in TOC (-72 g/kg), TN (-10 g/kg), K (-0.7 mg/kg), and Al (-30 mg/kg); (2) an increase in soil pH (+1.8), Ca (+88 mg/kg), Mg (+7.5 mg/kg), Mn (+0.3 mg/kg), and Fe (+6.9 mg/kg); and (3) no significant change in Na, Zn, and Cu. Wetland soils had higher concentrations (mg/kg) of Al-P (435), CaMg-P (42), FeMn-P (43), and Org-P (162) than those of 172, 11, 11, and 84 mg/kg, respectively, when compared with the pasture soils. The levels of water soluble P and KCl-bound P were comparable between wetland and pasture soils.  These results are important in establishing useful baseline information on soil properties in pasture and adjoining wetland prior to restoring and converting pasture back to its original wetland conditions. Our results suggest that conversion of wetland to beef cattle pasture was not environmentally detrimental because the levels of soil nutrients especially P and N in the improved pasture both showed decreasing trends after 65 years. The results further suggest that changes in soil properties due to changing land use could be long lasting.