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The Use of Fertilizer for Controlling Several Submerged Aquatic Plants in Ponds

1942; Wiley; Volume: 71; Issue: 1 Linguagem: Inglês

10.1577/1548-8659(1941)71[94

1548-8659

E. V. Smith, H. S. Swingle,

Water Quality Monitoring and Analysis

Various submerged weeds form tangled masses of vegetation in shallow, clear-water ponds in the Southeast. It is difficult or impossible to fish in such weed-infested ponds, and the weeds protect the small fish from carnivorous species so well that overcrowding develops and stunted populations result. Hence, the control of submerged weeds is an important problem in pond management. Commercial fertilizer has been used in the control of Najas guadalupensis, Potamogeton pusillus, P. angustifolius, and Chara sp. The following is the recommended procedure: Apply 100 pounds of 6–8–4 and 10 pounds of sodium nitrate per acre at each application, broadcasting the fertilizer over the weed-infested portion of the pond; make the first application in the winter and others at about monthly intervals until the weeds are covered with filamentous algae. The algae shade the weeds so that they become detached and float in large decaying masses. No fertilizer should be applied while the weeds and algae are decaying actively. Most of the weeds and filamentous algae disappear by the latter part of June. As the weeds decay, nutrients are returned to the pond and the water turns green or brown due to phytoplankton. The shading effect of phytoplankton tends to prevent re-establishment of the weeds. Chara may appear in a pond the first year it is fertilized, but usually disappears before the end of the summer and does not reappear.