level for the tissues, since higher levels inhibited dry-matter pro- 

 duction. This indicates that serious consequences might result from 

 the discharging of nutrient-rich waters into the Everglades marshes. 

 (J.B.) 



Keywords: productivity, sawgrass plants, nutrients, Florida (Everglades) 



II-E-4 



Broome, S.W. 1973. An investigation of propagation and the mineral 



nutrition of Spartina alterni flora . Ph.D. Thesis. North Carolina State 

 University at Raleigh. 126 pp. (Diss. Abstr. 34:4330-8) 



Germination studies of seed of Spartina alterni flora Loisel collected 

 from several locations along the coast of North Carolina have shown 

 that this grass produces large quantities of viable seed. The ger- 

 mination percentage is affected by maturity of the seed; consequently, 

 they should be collected as near the shattering stage as possible. 

 Seed should be placed in cold storage at 2-4° C. soon after harvesting and 

 submerged in estuarine water within a month to retain viability over 

 winter. 



Field experiments have shown that direct seeding can be an effective 

 method of establishing new stands of S. alterni flora on dredge spoil. 

 Seedlings can be expected to survive only in the upper half of the 

 natural elevation range of S. alterniflora at a particular location. 

 The aboveground standing crop of plant material produced from seed 

 in one growing season may approach the annual production of long- 

 established marshes. 



Regression analysis was used to examine relationships between nutrient 

 concentration in the plant tissue and/or soil, and productivity of 

 S. alterniflora in natural stands. Variables found to be negatively 

 associated with yield include salinity of the soil solution, manganese 

 concentration in the plant tissue and soil, and sulfur concentrations 

 in the plant tissue. Concentration of phosphorus (P) in the plant tissue 

 and soil were found to be positively related to yield. Regression 

 equations for predicting standing crop of nutrients from dry weight of 

 the grass are presented. 



Increased growth of S. alterniflora in response to applications of 

 nitrogen (N) and P fertilizers indicates that the productivity of salt 

 marshes is limited by the supply of these nutrients. Yields were increased 

 significantly by additions of N to a salt marsh growing on a substrate 

 of sand and increased about threefold when both N and P were supplied. 

 In a marsh developed on finer textured sediments, N fertilizer doubled 

 the standing crop of short Spartina , but there was no response to P. 

 At least a part of the reason for the low productivity of short 



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