WHY FERTILIZE PONDS?
Figure 7: Measuring phytoplankton abundance by arm and hand. DIFFERENCES BETWEEN CHEMICAL FERTILIZERS AND MANURES Chemical fertilizers are concentrated nutrients for green plants. The qualities that have made them popular in modern agriculture are: 1) they can be stored for a long time, and 2) relatively little is needed since the nutrients are in a concentrated form. These are important advantages over manures if labor and transportation are costly. Two disadvantages of chemical fertilizers, especially for isolated farms operated on a limited budget, are that they are usually expensive and available only from commercial suppliers. Another important consideration about chemical fertilizers is their potential for being wasted. Adding chemical fertilizer to a pond initially stimulates phytoplankton growth. However, if too much is added plankton can become so dense that sunlight penetration through the water is restricted. When this happens algae cells may have more than enough nitrogen a
