ID

CNRE-126NP

Authors as Published

Authored by Dr. David Crosby, Assistant Professor and Extension Specialist, Fish Health, College of Agriculture, Virginia State University; Dr. Brian Nerrie, Assistant Professor and Extension Specialist, Aquaculture, College of Agriculture, Virginia State University and Cynthia L. Gregg, Extension Agent, Agriculture and Natural Resources, Virginia Cooperative Extension, Brunswick County

In Virginia, there are more than 80,000 farm ponds. These ponds have multiple functions for their owners:  irrigation, flood control, recreational fisheries, livestock watering, aquaculture and wildlife habitat. For many of these uses, water quality and pond productivity can be improved by adding agricultural lime (aglime). Pond productivity is the utilization of sunlight to stimulate the plant ecology for sustainable pond life.

Waters in Virginia lack the alkalinity (ionic concentration of CO3= and HCO3-) and hardness levels (ionic concentration of Ca++) necessary to have a productive ecology for plants and fish. By adding agricultural lime (aglime), calcium carbonate will accomplish this task and improve water quality. 

By liming a pond, it corrects the condition of low mineral content that is stressful for fish and increase nutrient availability. It also prevents extreme diel (24 hours) swings of pH that can result in killing fish fry, thusly affecting reproduction, which are some of the keys to appropriate pond balance.

Water quality of most ponds is influenced by the muds (soil) at the bottom of the pond. The mud (soil) chemistry dictates the water chemistry of the pond. If the muds (soil) are high in calcium carbonate level due to limestone deposits, the pond should have adequate levels of carbonates (alkalinity) and calcium (hardness). 

Many farm ponds don’t have limestone deposits or waters flowing over limestone that feed the pond. This results in many ponds having low alkalinity and calcium levels that make a pond unproductive and its fish population out of balance.


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Publication Date

December 8, 2020