1986-12-08_GENERAL DOCUMENTS - M1977493 (2)

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20 The great variability in germination for the various seeds is not easily explained. Differences between series 1 and 1A, however, can be readily com- pared by assessing the combined results of germination and survival for the three comparable plants in each series. This comparison shows that, of a total 1,200 wheatgrass, alfalfa, and rye seeds planted in series 1, 920 seeds germinated and 271 survived after 10 weeks to furnish a 77 percent overall germination and 23 percent survival of the total seeds planted. The results in series 1A show that with sludge present in the top 3 inches of tailing the germination rate was 69 percent, but that the survival rate was 32 percent of the total seeds planted. Addition of sludge to the top 3 inches of tailings thus appeared to be beneficial to overall plant survival. For evaluation of plant-species response and the effect of sludge-layer depths on germination and survival, the overall combined results from both test series were compared. These comparisons show that the combined germina- tion and survival percentages for wheatgrass, alfalfa , and rye grain plant species were 76-29, 61-7, and 81-46, respectively. The grain and wheatgrass showed major advantages over the legumes. The overall germination and sur vival of plants with sewage sludge layers at depths of 3, 7, 11, and 15 inches were 71-22, 75-27, 76-27 , and 70-33, respectively. These data indicate that the test with the sludge at a 3-inch depth was the poorest of the group. How- ever, the vegetation appeared healthier in plots with the shallow sludge layers. Once the roots penetrated the sludge layer, the plants took on a much healthier appearance and were much hardier than plants with roots only in the tailings. Comparison of series 1 and lA plots were made at 10 weeks after which the series 1 plots were disassembled for other tests. The LA plots were permitted to grow for 10 months to determine the effect of longevity on the plants and especially the deep-rooted tomato plant. The plots were systematically dis- assembled at 10 months to evaluate the plant and root systems of all the tomatoes. Results of this examination are presented in table 3. TABLE 3. - Plant and root growth of tomatoes Sludge Weight of plant and Length of plant and main root, position, recoverable roots, inches inches grams Plant Root Total 3 1411 289 19.5 '108.5 7 193 64.5 54.5 119 11 97 67.5 33.25 70.25 15 69 50 32 82 Includes 70 grams pruned from plant while growing so as to keep plant in bounds of plot. 2Does not include length of plant pruned during growing period. 3The main root system grew only in the surface layer of sewage sludge and tailings. Inspection of the root systems showed that practically all roots for the sludge at depths of 7 , 11, and 15 inches had grown and remained in the upper