(Table 19). This is the first fertilizer response for the tall form in 

 any of the North Carolina experiments. Salinity was consistently lower 

 under the tall form than under the short form but remained well below 

 sea strength under both. 



c. Effect of 2 Years of Fertilization on a Seeded Stand of 

 Sporting altemi flora . This seeding was done in April 1973 on an is- 

 land in Core Sound near new Drum Inlet, North Carolina (Woodhouse, 

 Seneca, and Broome, 1974] . The island surface lies within the inter- 

 tidal zone and is inundated by seawater at each high tide, except 

 for periods of strong southwesterly winds which lower the water level. 

 During low water and the absence of precipitation, the increased salt 

 concentration near the soil surface becomes highly detrimental to the 

 development of Spartina alterni flora , killing some plants each summer. 



This experiment, which began 11 July 1973, included two rates of 

 phosphorus and four rates of nitrogen in a complete factorial design. 

 There were strong indications that year that the addition of nutrients 

 improved the ability of the seedlings to overcome salt stress (Wood- 

 house, Seneca, and Broome, 1974). Fertilizer was applied in split appli- 

 cations again in 1974 (30 April, 5 June, and 31 July). Response was 

 greater than in 1973 with a sevenfold increase for nitrogen plus phos- 

 phorus. Nitrogen response continued upward, in the presence of applied 

 phosphorus, through the highest nitrogen rate, 672 kg/ha N (Table 20). 



The application of nutrients does not have any direct effect upon 

 the salt buildup problem. It did enable the plants to grow at a more 

 rapid rate when conditions were favorable. The addition of nutrients 

 brought about rapid stabilization in doubtful areas. 



VI. MARSH DEVELOPMENT 



The early stages of the development into marsh of several planted 

 areas were described in Woodhouse, Seneca, and Broome (1974). This 

 section adds a year to that initial account on three sites. The first 

 site is the plant source experiment at Snow's Cut, planted in 1971 

 (Table 6) . Dry matter production in the fourth year seems to be 

 leveling off at about 12 metric tons per hectare. Visually, the 

 planted area is indistinguishable from nearby natural marsh; it appears 

 to be approaching a fairly stable condition. 



The second site was seeded near Beaufort in 1972. Plant growth at 

 this site was low in 1974 (Table 8) , only a little over 4 metric tons 

 per hectare, no more than in 1973. Development of this seeded marsh 

 ceased at a low level of production, less than one-third that of the 

 Snow's Cut planting. This may reflect the origin of this planting, 

 Oregon Inlet seed. Although Oregon Inlet plants have grown satisfac- 

 torily at Snow's Cut, a low salinity-high nutrient site experience at 

 Pine Knoll Shores in 1974 has indicated that plants from the Oregon 



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