f. Fertilization. Seedlings are usually more responsive to ferti- 

 lizer than transplants. First-year growth can be increased substan- 

 tially by fertilization in nutrient -poor environments. Top dressings 

 of about 100 kilograms per hectare of nitrogen (90 pounds per acre) 

 and 25 kilograms per hectare of phosphorus (50 pounds per acre P2O5) , 

 applied in late June and again in late July, are suggested where nu- 

 trient deficiencies are suspected. Nitrogen should be from ammonium 

 sulfate and phosphorus from a soluble source such as treble super- 

 phosphate. Application should be on the exposed soil surface at low 

 tide. 



VIII. SUMMARY AND CONCLUSIONS 



The results from new experiments established on eroding shorelines 

 on Bogue Sound indicated that rhizomes of Spartina altemi flora, with- 

 out attached well -developed culms, were worthless as propagules within 

 the intertidal zone. Neither fertilization in the nursery nor in the 

 furrow at transplanting affected final establishment of vegetation on 

 this shoreline. Plant growth from seeds in peat pots were the same as 

 field-grown transplants, but were more expensive to produce and more 

 difficult to transplant. Plants from a local source were superior the 

 first growing season to plants grown locally from foreign seeds. Dif- 

 ferences between sources of plant material transplanted at Snow's Cut 

 largely disappeared in the fourth year after transplanting. 



Seeding was unsuccessful on a Bogue Sound shoreline because of the 

 exposed location. Transplants spaced 1.5 and 2 feet produced sub- 

 stantially better stands than the normal 3-foot spacing in the first 

 year. Spartina altemi flora marsh, destroyed by land development 

 activities 2 years earlier, was successfully reestablished through 

 transplanting on an eroding shoreline in one growing season. 



The dominance of the ammonium form of nitrogen and the low ambient 

 oxygen concentration normal to soils in the intertidal zone were op- 

 timal for the growth of Spartina altemiflora. The inability of this 

 plant to utilize nitrate effectively appears to be partially a result 

 of a low uptake capability and an inability to translocate nitrate. 



A young stand of Spartina altemiflora on a sandy substrate con- 

 tinued to withstand and respond to high inputs of nutrients through 

 the fourth year. Similar results were obtained through the third 

 year on an old stand of the short form growing on a fine-textured sub- 

 strate. Fertilizer applications were highly beneficial in enabling 

 the development of a seeded Spartina altemiflora stand, subjected 

 periodically to severe salt stress. 



Specifications for transplanting and for seeding Spartina altemi- 

 flora are included in this report. 



71 



