hand, they do demonstrate the potential for growth that exists in the 

 species, given adequate moisture and nutrient supplies. 



b. Chemical Composition 



The data on chemical composition and nutrient uptake from the two 

 experiments are shown in Tables 10 and II. For most nutrients, there is a 

 tendency, not uncommon in perennial grasses, for the concentration in the 

 plant to decline as the season progresses and maturity approaches. In both 

 experiments, nitrogen, potassium, and to a lesser degree, phosphorus and 

 sulphur, follow this pattern. Nitrogen illustrates this pattern in Figure 

 7; calcium, magnesium and sodium contents did not appear to form any very 

 consistent seasonal pattern. 



c. Nutrient Uptake 



Since the concentration of all nutrients in the plant was quite 

 low, except in a few instances very early in the season, dry matter yield 

 largely determined the seasonal distribution of the uptake of nutrients. 

 This results in essentially a straight line from shortly after the initia- 

 tion of growth until very nearly the end, as illustrated for nitrogen in 

 Figure 8. Such an uptake pattern indicates a continuous need for nutrients 

 throughout the growing season, and tends to support split applications, 

 particularly for nutrients such as nitrogen which may be lost rapidly 

 from these sands. 



The amount of nitrogen harvested in the above-ground portion of the 

 plant at the end of the season (42 pounds at the Ocracoke site) is of some 

 significance. If one were to assume a recovery of applied nitrogen of 40 

 percent, which seems optimistic for these conditions; this would suggest 

 the need for the application of over 100 pounds of nitrogen per acre per 

 year for full growth of American beachgrass the first year. 



d. PI ant Ana I yses 



In addition to data presented in the previous sections, analyses 

 were made on a limited number of samples collected from eight other sites, 

 one or more of which involved dune panic grass or sea oats. These samples 

 were taken in late June and early July and were from simple replicated 

 tests of an observational nature which had been underway from I to 4 years 

 at the time of sampling. The analyses, along with the dry weight production 

 for the 1965 season, are shown in Table 12. Certainly, inferences drawn 

 from this one set of samples can only be of a very prel iminary nature. Even 

 so, several points appear to be worthy of note. 



(I) Nitrogen content is affected very materially by fertilization 

 and there appear to be differences in nutrient content between the grasses. 

 Dune panic grass was substantially higher in phosphorus and potassium than 

 American beachgrass but similar in nitrogen content where the two grasses 

 were growing together (see footnote in Table 12). 



22 



