success and may affect the planting procedure. The goal of marsh planting on 

 eroding shores is to speed up the establishment process under conditions which 

 have discouraged or prohibited natural invasion. An ample supply of nutrients 

 is one key element in assuring the accelerated rate of growth that is usually 

 required. Fertilization is primarily an establishment tool and is usually 

 necessary for nutrient-deficient soils along high-energy shores only. 



Nutrient deficiencies are much more prevalent in the subsoil materials 

 exposed along eroding shorelines than in dredged materials or alluvial 

 deposits. For this reason, the use of fertilizers in erosion control 

 plantings should be considered to be prudent insurance unless it is clearly 

 determined to be unneeded. Observed response to the application of nutrients 

 on marsh plantings under brackish and saltwater conditions has been limited to 

 nitrogen and phosphorus. Benefits from the addition of potassium or micro- 

 nutrients have not been identified and appear unlikely. Soil tests used to 

 estimate available phosphorus in agricultural soils appear to be fairly 

 reliable in identifying the extremes in intertidal soils, i.e., the acutely 

 deficient soils and the soils well supplied with phosphorus. There are, 

 however, no practical testing procedures that can be relied upon to predict 

 available soil nitrogen. If information is lacking on similar soils nearby, 

 the only safe approach is to add nitrogen or, as a minimum, apply it to a part 

 of the planting and carefully observe the results. 



1. Types of Fertilizer. 



The lack of reported information on the response of salt marsh plants to 

 fertilization in some cases is due to the use of unsuitable forms of nitrogen. 

 Nitrate undergoes rapid denitrif ication under anaerobic conditions and may be 

 quickly lost (Patrick and Makapatra, 1968). Also, ammonia is utilized more 

 efficiently than nitrate by smooth cordgrass, which is just the reverse of 

 most upland plants (Gosselinck, 1970; Woodhouse, Seneca, and Broome, 1976; 

 Mendelssohn, 1979). This is probably true of other marsh species because 

 ammonia is the normal form of nitrogen existing under anaerobic conditions. 

 Ammonium sulfate is commercially available and is usually an economical source 

 of nitrogen for marsh use. Diammonium phosphate should be an equally good 

 source. The urea and ureaformaldehyde forms of nitrogen were found to be 

 ineffective in marsh fertilization in recent tests (Broome, Seneca, and 

 Woodhouse, in preparation, 1983). 



The form of phosphorus used in marsh fertilization is not critical. The 

 solubility of most phosphorus compounds is enhanced by an anaerobic environ- 

 ment. Acute phosphorus deficiencies can usually be anticipated through soil 

 tests. Also, high phosphorus fixation is usually indicated by the presence of 

 a yellowish or reddish substrate rather than the dark colors of reduced soils. 

 Any of the standard soluble phosphatic fertilizers such as concentrated 

 superphosphate and diammonium phosphate are satisfactory and economical. 



Some slow-release fertilizers can be useful in marsh planting. Broome, 

 Seneca, and Woodhouse (in preparation, 1983) found osmocote and magnesium- 

 ammonium-phosphate (mag-amp) to be very effective on intertidal marsh, when 

 applied in the planting hole or furrow. Osmocote is a soluble fertilizer, 60 

 percent ammonia and 40 percent nitrate, encapsulated with multiple polymeric, 

 semipermeable coatings . The slow-release characteristics of mag-amp are due 

 to its low solubility, which can be controlled through granule size. It is 



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