Soil Temperature and Sewage Sludge Effects on Plant and Soil Properties

摘要

A field experiment was conducted to determine the influence of soil temperature and sewage sludge on growth and composition of corn (Zea mays L.). Changes in soil organic matter, extractable metals, pH, bulb density, aggregation, fecal coliform, and fecal streptococcus were determined. Soil temperatures studied were 16, 27, 35, and 22 C (ambient). Sludge was applied at rates of 0, 56, and 112 metric tons per hectare. Corn yields and growth were reduced by 16 C soil temperature, and increased by heating the soil to 35 C in 1976, but the warmer soil did not significantly increase yields in 1975. The effects of soil temperature on heavy metal concentrations in plants varied according to year, metal, and plant part. Zinc concentrations generally increased with increased soil temperature. Sludge increased concentrations of Zn, Cu, Ni, and Cd in corn, radishes, legume and small grain tissues. Cd increased significantly in corn seedlings with soil temperature increase, but not in stover. The highest rate of fecal coliform and fecal streptococcus addition and the longest survival times in soil were on plots receiving the highest sludge application. Survival time varied directly with soil temperature.