Field Assessment of Vegetation Formation Following Direct Seeding of Smooth Cordgrass Seed Using Two Aerial Applicators, Commercial Fixed Wing Airplane and Airboat.

Direct seeding using aerial applicators is very appealing and hardly matched by other planting techniques because of its speed, ease, and versatility of getting into remote areas inaccessible by land vehicles or boats. It can be used to conduct large-scale planting for habitat restoration and quick remediation of destructed habitats due to periodical massive marsh die-back or hurricanes. Aerial seeding of smooth cordgrass (Spartina alterniflora) seed was conducted using a commercial fixed-wing airplane on March 31, 2010 on Bayou DuPont marsh created site-2 near Belle Chase, LA. The seed for aerial seeding was harvested from experimental smooth cordgrass polycross line (PolyC15). The plane was calibrated by adjusting a hopper opening at a given air speed to deliver seed in the rate of 10, 20, and 30 lbs/A in 40 x 1,000 ft strips each separated by 56 ft unplanted area. Based on the observation made two weeks after aerial seeding, about 90% of the seed was not visible in most parts of the seeded area. This was due to the rapid change in the planted area from mostly wet and inundated land fractions into dry land with less inundated land fractions caused by the de-watering process. About 75% the the area became dry and only about 10% of seed remained visible in the planted area. 80% out of the remaining seed has germinated two weeks after planting. Dense vegetation was observed in Mid October of 2011 mostly in the middle strip where moisture found in most of the time. By mid November, a high quantity of viable seed was produced. Another direct seeding conducted using an airboat at Lake Pontchartrain site near Lacombe, LA, produced homogeneous dense vegetation using a seeding rate of 20 lbs/A. Four months after seeding, mature vegetation was produced with an average stem density of 11 stems/ft² in two out of three experimental plots.