Soil Chemistry Properties Under Two Different Management Practices: Clipped Saint Augustine Grass Lawn and Annually Burned Cajun Prairie

Prescribed burning every two or more years is the recommended management practice to remove unnecessary invasive plants and to enhance the regrowth of desirable plants for the development of a fire-dependent plant community native to southwestern Louisiana. A portion of Saint Augustine grass lawn at Louisiana State University at Eunice (LSUE) was converted into a Cajun Prairie restoration plot in 1989. Since 1991, the adjacent lawn has been clipped weekly, whereas the prairie has been burned every January. The objective of this study was to determine the soil chemical properties of clipped lawn and burned prairie plots. Each plot (12 m x 104 m) had four blocks (replications). Soil samples from the 0-10 cm depth were taken from each block for each plot in December 2002, March 2003, and June 2003. They were analyzed in the laboratory for soil chemical properties: pH, organic carbon (OC), electrical conductivity (EC) as a measure of soluble salts, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), zinc (Zn) and copper (Cu). Extractable soil P, Ca, Mg and Na were significantly greater in the burned prairie than in the clipped lawn. In the burned prairie from December to June, Fe increased, whereas pH, EC, P, K, Na, Cu, and Zn decreased. The results suggest that the annually burned restored Cajun Prairie provided greater nutrient deposition into the soil than the clipped Saint Augustine lawn

Soil Chemical Responses to Fire Seasonality and Frequency in a Texas Grassland

On a clay-loam mixed grassland dominated by honey mesquite (Prosopis glandulosa Torr.) in northern Texas, we quantified soil pH, soil organic carbon (OC), electrical conductivity (EC), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) in response to various effects of summer and winter fire treatments from 1991–1996. We conducted summer fire between August and September, and winter fire between January and March. Treatments that included summer fires increased soil pH, EC, Na, and Cu and temporarily decreased soil OC and Mn (P ≤ 0.05). The winter fire treatment had a long-term effect of increasing Fe and decreasing Mn. Changes in soil pH were positively correlated with EC, Ca, P and Na, and negatively correlated with K, Fe, Mn, and Zn (P ≤ 0.05). With the exception of the increases in EC and Na, and temporary loss of OC and Mn, fire treatment regimes that included summer fires did not appear to deplete soil nutrients and may be an acceptable strategy for managing mesquite-dominated grasslands

Soil Chemical Responses to Fire Seasonality and Frequency in a Texas Grassland

On a clay-loam mixed grassland dominated by honey mesquite (Prosopis glandulosa Torr.) in northern Texas, we quantified soil pH, soil organic carbon (OC), electrical conductivity (EC), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) in response to various effects of summer and winter fire treatments from 1991–1996. We conducted summer fire between August and September, and winter fire between January and March. Treatments that included summer fires increased soil pH, EC, Na, and Cu and temporarily decreased soil OC and Mn (P ≤ 0.05). The winter fire treatment had a long-term effect of increasing Fe and decreasing Mn. Changes in soil pH were positively correlated with EC, Ca, P and Na, and negatively correlated with K, Fe, Mn, and Zn (P ≤ 0.05). With the exception of the increases in EC and Na, and temporary loss of OC and Mn, fire treatment regimes that included summer fires did not appear to deplete soil nutrients and may be an acceptable strategy for managing mesquite-dominated grasslands