1987-01-08_REVISION - M1977493 - Laserfiche WebLink

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~. 19 other was sewage sludge. Both are bulky organic materials which, when mixed vi[h tails, yield soillike textures and mineral, air, and water relationships. Plots prepared with Kennecott Copper tailings and 5 to 15 tons per acre of each of the two waste-derived products indicated the additives to be benefi- cial to both vegetative germination and growth. The sewage sludge produced better growth than the commercial compost, and plots treated with either mate- rial demonstrated much better growth when additional fertilizer was added. Buried Organic Layers As noted, one of the difficulties in growing plants on tailings is the lack of organic matter and accompanying microbial populations. Results of initial tests made by mixing the equivalent of 5 to 15 tons per acre of sludge or compost into the surface 3 inches of tailings were encouraging. Subse- quently, tests were made on the use of tailings pelletized with sewage sludge to form a surface layer and on the effect of buried layers of sewage sludge on the pH and salinity of the tailings being tested. A series of tests was made in which 2-inch layers of sewage sludge were placed at different depths in barrels containing an 18-inch depth of Kennecott tailings. Sludge was placed at depths of 3, 7, 11, and 15 inches below the surface of the tailings. In another test series, the layering pattern was unchanged but an additional equivalent of 15 tons per acre of sewage sludge Gas mixed into the top 3 inches of tailings. Crested wheatgrass, Ranger alfalfa, and rye grain seeds were planted for both series of tests with barley used as the fourth seed in one test series, and a small transplanted tomato vas used as the fourth plant variety in the-other series of tests. Table 2 shows the number of. plants germinating per 100 seeds 2 weeks after planting and the number surviving at the end of 20 weeks. TABLE 2. - Germination and survival of four species of plants with 2-inch sludge layers at various depths Pa nth of ~ Nnmhar of nlanhel ~\ sludge layer Crested wheat rass Ran er alfalfa R e rain Barle rain below surface, Germi- Sur- Germs- Sur- Germi- Sur- Germi- Sur- _ inches nation usual nation usual nation usual nation usual SERIES 1 NO SLUDGE ALM IXED INTO TOP 3 INCHES OF TAILINGS 3 71 4 70 8 83 23 89 0 7 88 37 78 4 92 39 97 21 11 73 42 81 9 89 43 94 14 15 53 28 59 6 83 28 45 2 SERIES lA 15 TONS PER ACRE SEWAGE SLUD GE IN T OP 3 INCHES OF TAILINGS 3 90 26 36 S 74 64 ( ) ( ) 7 80 24 41 4 71 56 (a} (a} 11 78 15 59 1 78 53 (z) (2) 15 77 56 67 19 80 60 a a -i;ermination rate at 2 weeks ZO-week growth. `Tomato plants approximately of the barrels. after planting and survival oY plants aster 2 inches high were planted in the fourth quadrant ,. ;. ii -0L ~:;i is .. ii~l:~`~'G} °,,. ~i r.; %~?; i' i.