**2. Hydroseeding**

Hydroseeding is one of the methods of ground re-vegetation to stabilize bare soil surface to prevent soil erosion. It calls for the use of cellulose mulch material mix with a tackifier acting as binder. The cellulose binder mulch, together with the grass seeds, fertilizer and water are mixed inside the tank of hydroseeding machine to form into consistent and homogeneous slurry and then hydraulically sprayed to the ground. When sprayed, the cellulose fiber mulch together with the fertilizer and the grass seed will act as an absorbent mat, holding enough moisture to allow proper germination of the grass seeds and the same time forming a firm blanket cover to the soil surface even before the grass seeds germinates to prevent soil erosion. The cementitious geobinder forms a permeable curst on the soil surface which control water, soil and wind erosion. The geobinder is a non toxic cementitious binder that safely holds the grass seeds uniformly in place, prevents surface erosion and water evaporation in the soil. The cellulose fiber mulch which is biodegradable and in time will revert back to organic matter, enhances vigorous establishment of the grass ground cover. The application of hydroseeding process can be considered for temporary and permanent erosion control, seeding and mulching.

Hydroseeding is now a widely used process of controlling soil erosion abroad. Countries like the United States use this type of grass planting since the process is fast, efficient, and economical. It is more effective than conventional seeding and more economical than conventional sodding. In the Philippines, hydroseeding is first introduced in the Subic-Clark-Tarlac Expressway Project. Reports show that the adoption of hydroseeding is advantageous to the said project. Centrocema Pubescens (Centro) and Calopogonium Muconoides (known as Calapo) are the plants used in the project. The application of hydroseeding method yields the following observations and conclusions: (a) Hydroseeding planting process is the fastest way of preventing soil erosion; (b) the temporary seeds will germinate forty-eight (48) hours after spraying and the planting seedbed of the embankment is already 100% stabilized even before the establishment of the permanent ground cover; (c) Aside from nursing the grass seeds, the planting seedbed stabilizer called "geobinder" holds the ground cover grass seed in place and other soil planting amelioration materials; (d) Less watering is needed once the ground cover grass seed is 100% established; (e) The mulch material serves as moisture retention absorbing mat and at the same time reduces the development of the undesirable weeds; (f) In hydroseeding, 10,000 to 15,000 square meters of planting seedbed can be accomplished in a day; (g) There is no rill or gully erosion in case of heavy rain once hydroseeding is in place; (h) The Pure Living Seed (PLS) population per square meter is guaranteed to be 70-75 Living Grass Seed; (i) Hydroseeding final end product will require only very little maintenance once the permanent ground cover is purely established. (BCDA, 2006)
