11. Factors Influencing Survival. 



By multiple correlation analysis, environmental parameters were tested for their 

 contributions to transplant success or failure. These data showed that no one factor 

 accounted for the success of a planting, and that extreme drought or extreme salinity could 

 cause total planting failure. Other variables, e.g., soil and air temperatures and carbohydrate 

 storage, contributed to planting success or failure, but never were responsible for total stand 

 failure. Both species survived best when soil moisture and precipitation were high, and soil 

 salinity and carbohydrate storage were low. 



12. Critical Soil Salinity. 



Laboratory experiments to determine critical substrate salinity levels showed that 

 shoredune panicum was least tolerant, followed by sea oats, while bitter panicum was most 

 salt-tolerant. The critical levels which resulted in 50 percent reduction in survival over 

 controls were (in micromhos per centimeter, 2:1 water-sand ratio): 1,830, 2,620, and 3,460, 

 respectively. 



13. Saltwater Inundation. 



Occasionally, inundation of backshore plantings by saltwater was the cause of total 

 planting failure, particularly during drought, or if accompanied by wave action, sand 

 deposition, or extended ponding of saltwater. However, a minor surge of from 1 to 2 days 

 was not always detrimental, and occasionally no adverse effects occurred. 



14. Sand Burial. 



Drifting sand of greater than 6 inches adversely affected transplant survival, and 

 accumulations over 20 inches resulted in total failure. 



15. Sea Oats Culm Selection. 



The largest available culms of sea oats had higher survival and attained sand-trapping 

 size more quickly than the smallest. However, all sizes made acceptable transplants. 



16. Bitter Panicum Culm Selection. 



Bitter panicum transplants survived equally well with or without an initial root system. 

 Long (> 1.5 feet) primary culms survived better than short ones (< 10 inches). From fall 

 through spring, mature primary culms were more successfully transplanted than tillers, but 

 the latter were preferable from late spring through summer. During winter, 3-foot primary 

 culms were broken in half and both halves planted with little loss of survival. 



17. Storage of Transplants. 



After harvesting, sea oats transplants were stored up to 4 days, and bitter panicum 

 nearly a month in freshwater, with no loss of survival potential. 



18. Irrigation. 



Freshwater irrigation before planting was essential on fence-built dunes, and would be 

 useful on beach plantings during drought. Postplanting irrigation did not improve transplant 

 survival during a period of near-normal rainfall, but may be beneficial during extended 

 droughts. 



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