about four times as much. Dahl, et al. (1975) found on Padre Island that 

 bitter panicum spaced 60 centimeters on centers, planted in a strip 15 

 meters wide, effectively stopped windborne sand by the end of the first 

 growing season. Closer spacing resulted in slightly more dune growth 

 only in the season of establishment. 



A graduated planting pattern, dense near the center and thinning 

 toward the outer edges, has been found to be more effective and less costly 

 than uniform spacing (Savage and Woodhouse, 1968; Seneca, Woodhouse, and 

 Broome, 1976). The wider spacing on the outer edges allows sand to reach 

 through to the center and build a ridge. This planting pattern produces 

 a dune with a more stable cross section and at less cost. 



A similar approach would be useful under conditions such as those at 

 Padre Island. A planting pattern that will annually accumulate 8 to 12 

 cubic meters of sand per meter of length consists of a four- or five-row 

 center strip with the plants spaced 45 centimeters on centers in a se- 

 quence of two rows spaced 80 centimeters apart, two rows 1 meter apart, 

 and two rows 1.3 meters apart, from the front and sides of the center 

 strip. This would result in a 15-meter-wide strip with fewer plants 

 but more efficient than a 15-meter-wide strip with the plants uniformly 

 spaced 60 centimeters on centers. 



6 Fertilization and Management . Bitter panicum responds 

 to fertilizer by speeding initial growth and early development of sand- 

 trapping capacity. Dahl, et al . (1975) reported fourfold increases in 

 growth of fertilized over unfertilized stands. However, fertilization 

 after the first year is usually neither necessary nor desirable on 

 active foredunes. Fertilization of a 15-month-old dune-width panicum 

 plot produced growth and sand-trapping capacity far in excess of sand 

 supply. This resulted in the retention of a high proportion of the 

 sand near the front of the dune and a steeper, less stable dune (Dahl, 

 et al., 1975). 



Suggested rate of fertilization is 100 to 180 kilograms of nitrogen 

 per hectare divided into two or three applications beginning in late April 

 or May. The addition of small amounts of phosphate may be beneficial in 

 some cases. Response to applied potassium is very unlikely in the salt 

 spray zone. ^ 



(b) Sea Oats . This is the predominant foredune plant along 

 most of the gulf coast and should be included with bitter panicum in all 

 foredune plantings. It is too dificult and expensive to propagate to 

 plant in a pure stand, but it will thrive under sand accumulations heavy 

 enough to smother bitter panicum. The inclusion of sea oats in the mix- 

 ture adds to stability of the planting as well as ensuring a seed supply 

 for natural recolonization of bare areas. Also, sea oats will persist if 

 conditions change and there is less sand movement, providing stabilization 

 when other pioneer plants disappear. 



j_ Planting Methods . Sea oats is transplanted in the 

 same way as bitter panicum. It is planted by hand on small, steep, or 



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