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22 <br /> As in previous tests the germination of seeds varied broadly and compari <br /> son of results was best made by comparing survival of plants at the conclusioi <br /> of 10 weeks. This comparison showed that the overall germination for all <br /> three seeds in the pelleted tailing test was 68 percent with a survival rate <br /> of 54 percent. Germination and survival rates for the specific seeds, in <br /> percent, were respectively, wheatgrass 78-70, alfalfa 63-46, and rye 63-46. <br /> At the 10-week time interval , few differences existed in the survival of <br /> plants in the 4-1/2- and 16-1/2-i-nch-deep buried sludge layer plots or betwee- <br /> the two chemicals used to make the pellets. However, visual inspection of th <br /> surviving plants showed markedly better plant growth for the shallower layer <br /> and for the Coherex binder. <br /> All plots reported on in tables 2 through 4 were maintained for at least <br /> a 10-week interval and the results are compared in table 5. <br /> TABLE 5. - Comparison of overall germination and survival of plants <br /> on buried sludge layer plots, percent <br /> No sludge added Sludge mixed in top Sludge mixed <br /> Plant 3 inches of tailings into pe lets <br /> Germi- Sur- Germi- Sur- Germi- Sur <br /> nations vivall nation vival nation viva <br /> Crested wheatgrass.. .. .. 71 28 81 30 78 70 <br /> Ranger alfalfa. . ... . . . . . 72 7 51 7 63 46 <br /> Rye grain. . . . ... . . . . .. . . 87 33 76 58 63 46 <br /> Overall. . . . . . . . . . . . .. . . . 77 23 69 32 68 54 <br /> Germination rate at 2 weeks after planting and the survival of plants after <br /> 10-week growth. <br /> The comparison clearly shows an advantage for the addition of sludge to <br /> the tailings, particularly in pelletized form. The pelleted plots were main- <br /> tained for a 10-month period before dismantling, and despite daily waterings <br /> for the first month and twice weekly watering thereafter, the bulk of the <br /> pellets were still coherent. The surface pellets had decrepitated to some <br /> extent, but those immediately under the surface retained their cohesive <br /> pelleted forms for the entire period. <br /> Combination of Pelletization and Buried Organic Layers <br /> A series of tests employing a combination of buried organic layers <br /> together with pelleted surface materials was established to determine the <br /> effects upon vegetative growth and pH values of the component materials. Fot <br /> plots were established using Kennecott tailings that had a pH of 7.8 when <br /> first obtained but which had decreased to a pH of 6.6 after several months' <br /> storage. Two replicate plots were established with a 2-inch sewage sludge <br /> layer placed under 15 inches of tailings capped by a 1-1/2-inch layer compost <br /> of, in percent, tailing 92.4, sludge 6.6, and chemical binder 1.0. The secoi <br /> two replicate plots were the same, except that the 2-inch sewage sludge laye: <br /> was placed under 3 inches of tailings and capped by pellets. <br />