1710 W MARINE VIEW DR 2024-01-03

permanent areas shall use soil amendments to achieve organic matter and permeability per- formance defined in engineered soil/landscape systems. For systems that are deeper than 8 inches complete the rototilling process in multiple lifts, or prepare the engineered soil system per specifications and place to achieve the specified depth. Fertilizers • Conducting soil tests to determine the exact type and quantity of fertilizer is recommended. This will prevent the over -application of fertilizer. • Organic matter is the most appropriate form of fertilizer because it provides nutrients (includ- ing nitrogen, phosphorus, and potassium) in the least water-soluble form. • In general, use 10-4-6 N-P-K (nitrogen -phosphorus -potassium) fertilizer at a rate of 90 pounds per acre. Always use slow -release fertilizers because they are more efficient and have fewer environmental impacts. Do not add fertilizer to the hydromulch machine, or agit- ate, more than 20 minutes before use. Too much agitation destroys the slow -release coating. • There are numerous products available that take the place of chemical fertilizers. These include several with seaweed extracts that are beneficial to soil microbes and organisms. If 100 percent cottonseed meal is used as the mulch in hydroseed, chemical fertilizer may not be necessary. Cottonseed meal provides a good source of long-term, slow -release, available nitrogen. Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix . On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded Fiber Matrix (MBFM) products. Apply BFM/MBFM products at a minimum rate of 3,000 pounds per acre with approximately 10 percent tackifier. Achieve a minimum of 95 percent soil coverage during application. Numerous products are available commercially. Most products require 24-36 hours to cure before rainfall and cannot be installed on wet or saturated soils. Generally, products come in 40-50 pound bags and include all necessary ingredients except for seed and fertilizer. . Install products per manufacturer's instructions. . BFMs and MBFMs provide good alternatives to blankets inmost areas requiring vegetation establishment. Advantages over blankets include: • BFM and MBFMs do not require surface preparation. • Helicopters can assist in installing BFM and MBFMs in remote areas. • On slopes steeper than 2.5H:1 V, blanket installers may require ropes and harnesses for safety. • Installing BFM and MBFMs can save at least $1,000 per acre compared to blankets. 2019 Stormwater Management Manual for Western Washington Volume 11 - Chapter 3 - Page 288