essential that the soil be taken Into account early as it will often dictate 

 the planting method and thus have a major effect on costs. Loose, sandy soils 

 are usually easy to plant; planting holes are readily opened by hand with 

 shovels, spades, or dibbles and are easily closed and firmed after 

 transplanting. Tractor-drawn planters work well on these soils and have a 

 relatively low power requirement. 



More compact, cohesive soils provide a more stable substrate for marsh 

 planting than the loose sands, but the planting process itself may be more 

 difficult. Cohesive or very compact sandy soils are usually stiff and resist 

 the opening of holes or furrows and the proper closing and firming after 

 planting. Planting openings in some fibrous peats are especially difficult to 

 close satisfactorily. The power requirements of tractor-drawn planters on 

 some compact soils are high enough to make this method impractical. Also, the 

 opening of planting holes by hand on such soils will be very laborous and may 

 become cost prohibitive. The power-driven auger is about the only practical 

 solution for this problem on the more difficult soils. The importance of 

 careful consideration of soil characteristics early in the planning process 

 can scarcely be overemphasized. 



(2) Salinity . Salinity is the one common factor that affects all 

 salt marsh plants. These plants must have some salt tolerance, a prime 

 requirement in this habitat. Some of the more tolerant species have the 

 capacity to excrete salt through special structures (salt glands) in their 

 leaves. A number of them possess another mechanism in their roots for 

 screening toxic ions and slowing their inward penetration (Waisel, 1972). 

 Plants of the regularly flooded, low marshes, such as smooth cordgrass. 

 Pacific cordgrass, and the mangroves, are well equipped to live and grow in 

 salinities up to 35 parts per thousand (sea strength). However, these plants 

 are usually quicker to establish and more productive in salinities below sea 

 strength. Seeds and young seedlings are usually more sensitive to salt 

 concentration than are established plants. 



Relatively little work has been done on salinity regimes of marsh soils 

 and their effect on plants under field conditions. Soil salinity is not easy 

 to investigate because of the high variability, in time and space, of salt 

 concentrations. The concentration of salt required to eliminate a particular 

 species from a site need not occur often or persist for more than a few hours 

 or days. Consequently, these events may elude fairly intensive sampling. 



Toxic concentrations usually do not develop in sandy marsh soils within 

 the regularly flooded zone. The salinity in such soils tends to remain close 

 to that of the surrounding water. However, this may not always be true of 

 fine-textured soils in which salt may accumulate through ion exclusion by 

 roots (Smart and Barko, 1978). Salt accumulation in the fine-textured marsh 

 soils is probably held to a minimum by the drainage normally provided by root 

 channels and animal burrows . 



Salt damage may occur on newly planted areas due to concentration through 

 evaporation in the zone between neap tide high water and spring tide high 

 water during periods of low rainfall and warm temperatures following spring 

 tides. This also occurs in sounds and bays subject to a wind setup with the 

 wind pattern resulting in extended periods of low water during hot weather, as 

 in Core Sound, North Carolina. Under these conditions, soil-water salinities 



26 



