(Table 5-4). The means for each of the soil biogeochemical variables measured at the restoration

site were found to be within the range of mean values measured at the reference sites, except for

the significantly higher soil microbial biomass levels (Cmb) (Table 5-5). The seasonal trend for

nitrogen mineralization fluxes over a 14 month period was for the rates to increase from winter

through spring, to peak during the middle of August, and to decline through the fall and winter

(Figure 5-3).

Pine Growth and Vegetation Control

 A concurrent study produced results from five years of pine growth and four years of

vegetation surveys showing imazapyr and sulfometuron-hexazinone herbicide treatments

significantly reduced longleaf pine seedling survival after four growing seasons. Imazapyr,

followed by hexazinone treatments produced significantly higher numbers of pine seedlings in

the out-of-the-grass stage when compared to the other treatments. Imazapyr also produced

significantly taller pines in the out-of-the-grass stage compared to the other trees. Imazapyr

treatments also resulted in the best control of the overall cover (%) and stem counts of the maj or

shrub species, while producing the highest level of herbaceous richness (Freeman, 2008). From

the same four years of pine data (2002-2006) both imazapyr and hexazinone produced better pine

growth when applied during the second growing season compared to the first (Table 3-6). They

both had higher survival rates as indicated by higher stand densities. Imazapyr produced the best

pine growth of all the treatments when applied during April instead of March. Hexazinone

produced better pine growth when applied in March (Table 3-6; McCaskill data, 2006).

Treatment Effects-Biogeochemical Indicators

 Imazapyr produced the highest monthly mean nitrogen mineralization rates while

sulfometuron methyl treatments produced the lowest monthly rates. Most of the herbicides

increased the nitrogen mineralization rates, but imazapyr was the only treatment to produce