Soil Rehabilitation Guidebook
[Soil Rehabilitation Guidebook Table of Contents]
Appendix 4. Procedures for hydraulic seeding and mulching5
Follow these guidelines for ground-based seeding:
- Wear eye protection and a respirator rated for fine dust during mixing. Although most binders are non-toxic, they absorb many times their weight in water. Do not inhale them.
- Only use mulch with mixing tanks with mechanical agitation.
- Begin filling the tank with water under continuous agitation. Add the fertilizer once the tank is half full.
- As the tank continues to fill, add the binder slowly to avoid lumps. Add mulch next (if included in a one-pass application), leaving space for the seed.
- Add the seed last, under continuous agitation.
- After all materials are added and the tank is full to the recommended capacity, agitate the slurry for at least 10 minutes to ensure uniform mixing. This can be done while traveling to the treatment area.
- Ensure that constant communication is maintained between the truck driver and the crew during application. When seeding is being done with a hose, radios may be required for areas not visible from the truck.
- Follow the equipment manufacturer's procedures for safe pumping and application. Wear eye protection.
- Operate nozzles in a fan-like motion when applying slurry so the material falls gently onto the ground surface.
- When working with a hose, use a shut-off nozzle, clamps, or a twisted or kinked end during shutdown and repositioning to make sure the hose does not "de-water," clogging the nozzle with seed, fertilizer and mulch.
- When at the end of the hose, always assume a secure stance when the pump starts – the pressure can knock you over! A wild hose can cause serious injury.
- Completely flush the tank and pump with clean water after use. Wash your hands before eating.
Follow these guidelines during helicopter seeding:
- Always wear protective goggles and earmuffs during mixing and while filling the bucket.
- Locate the staging area on level ground with enough clearance for the helicopter to manoeuvre. Ensure a downhill take-off path. Put flagging in nearby trees as wind indicators. Staging should be as close as possible to the seeding area, with a minimum elevation difference. A view of the treatment area from the staging area is beneficial but not essential. The helicopter fueling and staging area must be at least 100 m from the hydroseeder and filling site.
- Bucket filling sites should be at least 30 m from the mixing truck. This requires adequate filling hose. Paint a square on the ground to identify the bucket filling site.
- Always have at least two people for a helicopter operation ground crew: one to fill the bucket, one to operate the hydroseeder.
- Maintain radio contact with the helicopter pilot. Agree on standard signals for starting and completing filling so the ground crew is in the clear during bucket landing and take-off.
- Keep the path between the hydroseeder and the bucket filling site free of obstacles and materials.
- Minimize the time needed to fill the bucket under the hovering helicopter by maximizing pumping volume. One, large-volume hose makes filling fast and efficient. A shut-off valve on the hose minimizes spillage.
- Check that all equipment is working properly before starting to seed. Ensure that the helicopter, seed bucket motor, and tank pump all have adequate fuel supplies.
- Discuss safety and logistics with the helicopter pilot on-site before starting the operation. Preview the treatment area with the pilot to discuss the objectives, areas to avoid (such as bedrock), and rates of application.
- Make a test run with water in the seeding bucket to determine the application rate. Adjust rate of flow based on swath width, speed and height of application. Make sure you have the proper tools for adjusting the orifice of the seed bucket and for making minor repairs.
- After testing the bucket, pre-mix the slurry in the mixing tank. Add enough mulch or suspension agent to prevent the slurry from settling during the helicopter trip.
- The pilot's observation of ground wetness controls ground coverage. Ground markings are a useful aid, if feasible.
- Completely flush tanks and seed bucket with clean water after use.