Phosphorus and Potassium Fertilization of Sunfish Ponds

Abstract

The rate of fertilization with P2O5, 9 kg/hectare/application, currently recommended for woodland ponds stocked with largemouth bass and sunfish was reduced by one-half without significant reduction in sunfish production. Although further experiments need to be conducted with combinations of largemouth bass and sunfish, these results may be applied on a trial basis. Ponds with waters softer than 20 mg/liter total alkalinity and bottom muds more acid than pH 5.8 should be limed if P2O5 application rates are reduced to 4.5 kg/hectare. Results of the present study probably will not apply to pasture ponds, which usually are more eutrophic than ponds on wooded watersheds. Potash apparently can be omitted from pond fertilizers without reduction in fish production, although this practice is not suggested for waters with less than 1.3 mg/liter potassium.