Bottom soil samples were taken after each draining during a five-year period from a series of 12 small earthen ponds ranging in size from 0.70 to 1.39 acres. Except in one pond, drainings occurred one or more times annually. The ponds were used to produce one or more crops of fingerling fish each year. Species cultured were largemouth bass, bluegill, channel catfish and redeal' sunfish. Chemical analyses for pH, calcium, phosphorus, potassium, carbon and nitrogen were done on each sample. All ponds except one were fertilized and supplemental feeding was done on a limited scale in some of the ponds. The quality of the water supply was a significant influence for modification of the parameters included, with artificial enrichment also appearing to exert an important effect. Generally, the soils became more alkaline and richer in calcium. Phosphorus increased tenfold in one pond from beginning to end of the period and potassium showed a moderate rate of increase although the fertilizer mix did not contain this element. Carbon increased in all instances, and nitrogen was also higher at the end of the period. The carbon to nitrogen ratio was narrower at the end of the study period in 10 of the 12 ponds than at the beginning. The two deviants had a narrow C/N ratio at the start.
