Response of marsh planting to rates of nitrogen is much more pronounced 

 than is phosphorus response. Growth of nitrogen-deficient stands of smooth 

 cordgrass in sandy substrates has been increased by nitrogen applications up 

 to 6 kilonewtons per hectare (600 pounds per acre) per year. Practical levels 

 of nitrogen for establishment are much less, probably in the range of 1 to 3 

 kilonewtons per hectare (100 to 300 pounds per acre). While there are no 

 reliable chemical tests for available nitrogen, the color of the grass itself 

 after establishment can be a useful indicator of nitrogen status. Dark green 

 leaves are usually well supplied with nitrogen. Lighter shades of green 

 accompained by the yellowing of lower leaves during the period of active 

 growth usually indicate inadequate nitrogen; however, this should not be 

 confused with the normal yellowing or browning that develops as most marsh 

 grasses and sedges mature. 



Phosphorus response is less common than nitrogen response and, where 

 needed, lower rates and less frequent application of this nutrient are usually 

 required. Broome, Seneca, and Woodhouse (in preparation, 1983) obtained maxi- 

 mum growth of smooth cordgrass with the application of about 1 kilonewton per 

 hectare of phosphate on a soil extremely deficient in this element. It is 

 doubtful that a greater amount than this in any 1 year would ever be 

 warranted . 



If soluble materials (ammonium sulfate and concentrated superphosphate or 

 diammonium phosphate) are used, they should be applied at a rate of 1 kilo- 

 newton per hectare of nitrogen and 1 kilonewton of phosphate at time of plant- 

 ing (3 to 4 weeks after planting if fertilizer is applied as a topdressing) . 

 In conventional mixed fertilizers, such as 10-10-10, the nxmber designations 

 represent the percentages (by weight) of nitrogen (N), phosphate (P2O5), and 

 potash (KoO) , respectively, that are found in the mixture. Therefore, the 

 amount of 10-10-10 fertilizer per hectare needed to provide 1 kilonewton each 

 of nitrogen and phosphate would be 10 kilonewtons (1,000 pounds per acre or 

 about 2.3 pounds per 1,000 square feet). A topdressing of an additional 1 

 kilonewton per hectare of soluble nitrogen, 6 to 8 weeks after planting, will 

 be helpful on deficient sites; a third application of 1 kilonewton 6 weeks 

 later will be advisable on acutely deficient sites. If conventional mixed 

 fertilizers are not used, phosphorous may be applied with the first applica- 

 tion of nitrogen or it may be combined with the split applications of 

 nitrogen. 



Slow-release materials, if used in lieu of soluble fertilizer, should be 

 applied at a rate of 1 kilonewton per hectare of nitrogen at the time of 

 planting. Slow-release materials should always be placed in the planting hole 

 or furrow. For conventional slow-release mixtures (14-14-14 or 16-8-12), 

 about 0.15 newton (0.5 ounce) of fertilizer should be placed in each planting 

 hole or along each 0.5 meter of the planting furrow. When slow-release 

 materials are used, no additional applications are necessary during the first 

 growing season. 



4. Maintenance Fertilizer . 



The use of fertilizer to aid marsh establishment is usually confined to 

 the year of planting. As soon as the new plants grow enough to begin signifi- 

 cant sediment accumulation, the need for fertilizer usually decreases sharply 

 or disappears. Thereafter, the native supply from substrate, accumulating 



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