Land application of combined sludge and secondary effluent
The effect of sewage sludge on soil, plant tissue, infiltration of the soil, and total biomass producation was studied. The crops grown for the project were alfalfa, wheat, and sorghum. For alfalfa the application rates were 0, 17.9, and 35.9 mt/ha (0, 8, and 16 ton/acre). There were two plots of wheat and sorghum, one had raw sludge applied and the other had lime-stabilized sludge applied. The application rates for the raw sludge plots were 0, 9.0, 17.9, 26.9, and 35.9 mtOia (0, 4, 8, 12, and 16 ton/acre). The application rates for the lime-stabilized plots were 0, 9.0, 17.9, and 26.9 mt/ha (0, 4, 8, and 12 ton/acre). The was an accumulation of metals in the soil but with the pH^S.O the metals should be relatively immobile. The plant tissue showed an increase in micronutrients for the project. Infiltration and total biomass production did not increase significantly with an increase in application rate. In the next year or two years the total biomass production should begin to increase, because the organic nitrogen should be converted to ammonium nitrogen by soil bacteria.