Magnesium concentration was lowest in the upper zone, ranging from 
about 38 ppm in the 2- to 4-inch layer to about 59 ppm in the surface 2 
inches. In the middle zone Mg occurred in larger quantities than in 
upper zone with the largest quantity in the surface 2 inches of soil. 
In general, Mg increased with soil depth in the lower zone. 
Potassium occurred in small quantities in all zones and did not 
exceed 34.1 ppm in any zone or at any soil depth. In comparison to 
K, Ca occurred in larger concentrations with a maximum of over 156 
ppm recorded in the 4- to 6-inch soil layer of the lower zone. 
Plantings along East Bay are subjected to continual wave action 
and are in a soil of low structural stability. Thus, survival within 
this area cannot be based solely on the adaptability of the plant 
species to the saline environment. The conditions that control washout 
immediately after planting must be considered (Figs. 12 and 13). 
In the lower zone of Block V, washout accounted for most of the 
mortality (Table 24). The range was from a low of about 29 percent 
for saltcedar to 100 percent for American bulrush, saltmarsh bulrush, 
gulf cordgrass and seeded smooth cordgrass. Thus, after washout and 
mortality only transplants of black mangrove and smooth cordgrass 
established. 
Washout accounted for most of the transplant losses in the middle 
zone. Of the 12 species transplanted, 100 percent of 10 species were 
lost and less than 12 percent of the other 2 species survived washout. 
In addition, the seeded plot in this zone was eroded. 
In the upper zone, the area seeded to smooth cordgrass was badly 
eroded and no germination was observed. In addition, all transplants 
of American bulrush were washed out. Species most resistant to wash- 
out in the upper zone were: gulf cordgrass, giant reed, black man- 
grove and saltgrass (Table 24). These same species ranked high in 
survival percent (Table 25). 
A comparison of survival and washout by zone in Block V shows 
over 26 percent of the transplants in the upper zone survived, re- 
gardless of species. This was significantly higher than from either 
the middle (0.0 percent) or lower (4.1 percent) zones. Percent wash- 
out was 52.2, 98.6, and 77.4 for the upper, middle, and lower zones, 
respectively. 
b. Height plantings. Based on observations, survival of black 
mangrove improved if two to four leaves of the transplants were ex- 
posed above the water. Thus, in October 1974, three blocks were 
planted to black mangrove of various heights to determine the rela- 
tionship between height, water depth, and survival. Two additional 
plantings will be made, one in the winter and one during the spring 
1975. 
7, 
