Dewey L. Tackett

Najas, Chara, and several filamentous algae species were controlled or eliminated by a single 0.1 mg!l (active ingredient) application of the herbicide Igran 80W, an 80% wettable powder formulation of terbutryn (2-tert-butylamino-4-ethyl-amino-6-methyl-thio-s-triazine), a commercial product registered for control of terrestrial vegetation but not now approved by the United States Environmental Protection Agency for use in ponds or other waters. The chemical, applied in summer, eliminated target plants within 2 weeks of application. The chemical is relatively nontoxic to fish at...

Catfish production varied 40 per cent among 12 ponds in a uniformity test. Survival, spawning, and trash fish made no significant contribution to this variation. Production was directly related to the amount of certain constituents found in the pond soils, namely, exchangable calcium, electrical conductivity, magnesium content of soil - water (1 :2.5) extracts, and nitrate nitrogen.

Nitrogen content of fertilizer formulations influenced the amount of organic and inorganic phosphorus found in the bottom soil of fish ponds flooded with water of medium hardness and alkalinity.