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<br />20. <br />The great variability in germination for the various seeds is not easily <br />explained, Differences between series 1 and IA, however, can be readi.Iy com- <br />pared by assessing the combined results of germination and survival for the <br />three comparable plants in each series, This comparison shows that, of a <br />total 1,200 wheatgrass, alfalfa,-and rye seeds planted in series 1, 920 seeds <br />germinated and 271 survived after 10 weeks to furnish a 77 percent overall <br />germination and 23 percent survival of the total seeds planted. The results <br />in series lA show that with sludge present in the top 3 inches of tailing the <br />germination rate was 69 percent, but that the survival rate was 32 percent of <br />the total seeds planted, Addition of sludge to the top 3 inches of tailings <br />thus appeared to be beneficial to overall plant survival, <br />For evaluation of plant-species response and the effect of sludge-layer <br />depths on germination and survival, the overall combined results from both <br />test series were compared, These comparisons show that the combined germina- <br />tion and survival percentages for wheatgrass, alfalfa, and rye grain plant <br />species were 76-29, 61-7, and 81-46, respectively. The grain and wheatgrass <br />showed major advantages over the legumes. The overall germination and sur-' <br />vival of plants with sewage sludge layers at depths of 3, 7, 11, and 15 inches <br />were 71-22, 75-27, 76-27, and 70-33, respectively, These data indicate that <br />the test with the sludge at a 3-inch depth was the poorest of the group, How- <br />ever, the vegetation appeared healthier in plots with the shallow sludge <br />layers. Once the roots penetrated the sludge layer, the plants took on a much <br />healthier appearance and were much hardier than plants with roots only in-the <br />tailings. <br />Comparison of series 1 and lA plots were made at 10 weeks after which the <br />series 1 plots were disassembled for other tests, The lA plots were permitted <br />to grow for 10 months to determine the effect of longevity on the plants and <br />especially the deep-rooted tomato plant. The plots were systematically dis- <br />assembled at 10 months to evaluate the plant and root systems of all the <br />tomatoes, Results of this examination are presented in table 3, <br />TABLE 3. - Plant and root growth of tomatoes <br />Sludge I Weight of plant andl Length of plant and main root, <br />position, recoverable roots, inches <br />3 1411 x89 19.5 x108.5 <br />7 193 64.5 54,5 119 <br />11 97 67,5 33.25 70.25 <br />15 69 50 32 82 <br />lIncludes 70 grams pruned from plant while growing so as to <br />keep plant in bounds of plot. <br />a Does not include length of plant pruned during growing period, <br />3The main root system grew only in the surface layer of sewage <br />sludge and tailings, <br />Inspection of the root systems showed that practically all roots for the <br />sludge at depths of 7, 11, and 15 inches had grown and remained in the upper <br />