1980-07-11_REVISION - M1977493 (8)

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to revegetate these types of sites, plant establishment is usually fair to good. However, after two or three years , most of the nitrogen applied at seeding time has either been utilized by the plants or leached out. Then the grass stand things and dies back to the point that it will not be effective in con- trolling erosion or maintaining aesthetic values. Nitrogen can be supplied to disturbed areas by: 1 . Covering with topsoil . The organic matter in the topsoil acts as a pool for nitrogen storage which is recycled by microorganisms. However, in some areas, particularly thsoe disturbed in the past, topsoil is not available . 2. Seeding of legumes or plants capable of fixing nitrogen from the air, but success in establishing and maintaining N-fixing plants on disturbed sites as Climax has beem limited . 3 . By the addition of nitrogen fertilizers. Objectives This nitrogen fertility study was designed to evaluate how often a disturbed area, stripped of topsoil , needs to be fertilized with nitrogen to maintain an adequate grass cover. Data generated from this study will include: 1 . Residual effect of nitrogen application for a period of one to five years. 2. Maximum lapse of time that a stand of grass on a disturbed soil can go without nitrogen and still maintain an adequate vegetative cover . Materials and Methods This study consisted of six fertility treatments re- plicated three times . The treatments were : 1 . Control ( no N) 2. 1st year - 60 lbs. N/A 3 . 1st year - 60 lbs. N/A, 2nd year - 60 lbs. N/A 4. 1st year - 60 lbs. N/A, 2nd year - 60 ljbs. N/A 3rd year - 60 lbs. N/A 5. 1st year - 60 lbs. N/A, 2nd year - 60 lbs. N/A 3rd year - 60 lbs. N/A, 4th year - 60 lbs. N/A 6. 1st year - 60 lbs. N/A, 2nd year - 60 lbs . N/A 3rd year - 60 lbs. N/A, 4th year - 60 lbs. N/A 5th year - 60 lbs. N/A The source of N was NH4NO3 ( 33-0-0 ) . 9-9