MICROBIAL ACTIVITY IN SOIL AND LITTER UNDERLYING BANDANE TREATED TURFGRASS AND CALCIUM ARSENATE-TREATED TURFGRASS

Microbial abundance and activity were examined in soil and litter under Kentucky bluegrass turf that received four annual applications of 39.2 kg ha-1 of bandane (polychlorodicyclopentadiene) or 439 kg ha-1 of calcium arsenate. No consistent effect of either herbicide on bacterial numbers was observed and fungal numbers were unaffected compared to control plots that received no herbicide. Amylase and invertase activities were significantly higher in undecomposed residues from treated plots. The rates of glucose utilization, nitrification of ammonium, and amylase synthesis were significantly lower in soil underlying treated turf than in control soil. The amount of undecomposed plant material was greatest in arsenate-treated plots in which microbial activity was most severely affected, suggesting that the increased residue accumulation was the direct consequence of a reduction in soil microbial activity. © 1978.