Spacing that is too wide will result in partial or total failure; spacing 

 that is too close is wasteful. Planting stock and costs are roughly pro- 

 portional to the number of hills planted. A 30- centimeter spacing re- 

 quires four times as many hills per unit area as a 60- centimeter spacing 

 and costs about four times as much. 



The spacing and pattern should be determined by the characteristics 

 of the site and the objective of the planting. A strip of American 

 beachgrass, 8 to 12 meters wide, planted 50 centimeters on centers will 

 effectively stop windblown sand sometime in the latter half of the first 

 growing season. Small blowout areas should be planted at a spacing of 50 

 centimeters or less. Stabilization of a large area of bare sand will 

 require a spacing 50 to 60 centimeters. It also means that costs may be 

 reduced in many instances by varying the planting pattern. For example, 

 in building a barrier dune, it is essential that part of the strip be 

 planted at a spacing that will stop sand movement sometime during the 

 first year (about 50 centimeters). However, it is not necessary to 

 plant the entire width of the planned dune at this density. Further, 

 the use of a graduated spacing pattern will result in a dune with a 

 more stable cross section and cost less (see Table 1). 



Where sand movement is less (1.5 to 3 cubic meters per front meter), 

 the following planting pattern on centers works well (front to back): 



2 rows 1.00 meter 



4 rows 0. 75 meter 



4 rows 0.45 meter 



4 rows 0. 75 meter 



2 rows 1.00 meter 



In both cases, the plantings are on equivalent spacing, obtained by 

 varying row spacing and distance in the row when the planting machine 

 cannot be adjusted to the exact row width desired. 



With this type of planting pattern the dune grows, for the first 2 

 or 3 years, more rapidly near the center of the planted strip, and slopes 

 gently to the outer edges. Sand accumulation increases near the edge as 

 the plants fill in and develop trapping capacity. However, by that time 

 the basic dune cross section has been broadened to a more stable form 

 with gradual slopes (Fig. 24). The planting costs are less than half 

 that of a uniform spacing. 



6 Fertilization and Management . American beachgrass 

 responds to fertilizers and the judicious use of fertilizers is useful 

 in the management of this plant. Response varies widely, and is least 

 under conditions of rapid sand accumulation, and greatest on old, leached 

 sands in back dunes and deflation plains. Growth on sites lacking fresh 

 sand may be increased tenfold by fertilization. Response is to nitrogen 

 and occasionally to phosphorus. Fertilization is also used during estab- 

 lishment to speed up rate of spread and increase sand-trapping capacity. 



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