centers will effectively stop the movement of sand across it sometime 

 in the latter half of the first growing season. Small blowout areas 

 should be planted solid at a 45-centimeter spacing or less; the stabi- 

 lization of a large area of bare sand requires a spacing of 45 to 60 

 centimeters. Costs may be reduced by varying the planting pattern. 

 For example, in building a barrier dune, it is essential that a part of 

 the strip be planted at a spacing of 45 centimeters to stop sand move- 

 ment sometime during the first year. However, since sand supply usually 

 limits dune growth, it is not necessary to plant the entire width of the 

 planned dune to this density. The use of a graduated pattern can result 

 in a dune with a more stable cross section as well as a saving in plant- 

 ing expense (Savage and Woodhouse, 1968). 



When the graduated planting pattern is used (Table 1), the dune grows 

 more rapidly near the center of the planted strip, sloping gently to the 

 outer edges. After 2 or 3 years, sand accumulation increases near the 

 edge as the wide-spaced plants fill in and develop trapping capacity. By 

 that time, the base of the dune has been broadened to a more stable form 

 (Fig. 24). The planting cost is less than half that of a uniform spacing 

 dense enough to trap the available sand. 



6 Fertilization and Management . American beachgrass 

 usually responds to fertilizers. The judicious use of fertilizers can be 

 useful in the management of this plant. Response varies widely. It is 

 least under the rapid accumulation of sand and greatest on old, leached 

 sands in back-dune and deflation plain areas. Growth on sites lacking 

 fresh sand may be increased as much as tenfold by fertilization. Response 

 is to nitrogen and to a lesser degree to phosphorus and potassium. Ferti- 

 lization is used during establishment to increase rate of spread and in- 

 crease sand-trapping capacity, and to revive old, starved stands. 



New stands often benefit from the application of 100 to 150 kilograms 

 of nitrogen and 30 to 50 kilograms of phosphate per hectare the first 

 growing season. Application should begin as soon as new growth is seen; 

 the dosage should be divided into two or three applications, spaced 4 to 

 6 weeks apart. Fertilization after the first year should be adjusted to 

 growth and appearance of the plants. 



The same general principles apply to old stands. Deficient stands 

 may benefit from up to 150 kilograms of nitrogen and 30 to 50 kilograms 

 of phosphate per hectare in two or three applications a year over 1 to 3 

 years. Healthy stands may be maintained with an application of 30 to 50 

 kilograms of nitrogen per hectare in early spring, at intervals of 1 or 

 more years. Fertilization should be adjusted to the growth and appear- 

 ance of the grass. Excessive growth promotes disease damage and plant 

 loss. 



Fertilizers containing nitrogen and phosphate in the suggested ratio 

 are not widely available. The same effect can be obtained by alternating 

 application of 10-10-10 or the equivalent with one or two applications of 

 a straight nitrogen material such as ammonium nitrate, ammonium sulfate, 

 or urea to approximate the desired ratio of nitrogen to phosphate. 



96 



