Effect of amendments on the microbial utilization of oil applied to soil.

Replicate field plots comprising a control, plus oil, plus oil and bacteria, plus oil and fertilizer (urea-phosphate; 27:27:0), and plus oil, bacteria, and fertilizer were monitored over a 308-day period for changes in bacterial and mold numbers. Changes in the chemical composition of the oil applied to the plots was followed by using chromatographic techniques. Application of fertilizer resulted in a stimulation of bacterial numbers and in the rate of utilization of n-alkane components of the saturate fraction. The application of oil-utilizing bacteria, however, resulted in only a slightly accelerated rate of utilization of n-alkane components of chain lengths C20 to C25. The isoprenoids, phytane and pristane, were still present in gas-liquid chromatography profiles after digestion of the n-alkane components of the saturate fraction. Those plots which received fertilizer showed an accelerated rate of recovery of native vegetation.