during the summer. Smith and Svdngle (I9U1) concluded that vnnter fertili- 

 zation of blue^i^ill ponds in the South is inadvisable because of slow fish 

 growth in that season. 



The recommendations given here are generalized and may not apply to 

 specific cases. Nelson (I9UI), for example, found that the addition of 

 fertilizers to shallow ?rras disturbed spawning beds and hindered the sein- 

 ing of bass fry. This difficulty was eliminated by applying the entire 

 amount of fertilizer to the center of the pond. Rounsefell and Everhart 

 (1953) believed that investigators usually place excessive emphasis on a 

 single factor with the result that recommendations and conclusions concern- 

 ing pond fertilization vary without reason, and the process reverts to trial 

 and error in different localities. 



Techniques Contributing to Maximum Production 



Fertilization, although specifically a problem of nutritional chemistry, 

 has other considerations of equal importance. Draining the pond, as pre- 

 viously indicated, oxidizes bottom soils and facilitates crop removal. In 

 addition to these functions, it permits control of aquatic vegetation and 

 competitive or injurious organisms. Ponds are usually drained at the end 

 of the grovring season and are allowed to overwinter in fallow (Schaeperclaus, 

 1933). Nutritionally poor bottoms may be seeded with a legume in early 

 spring and the crop plowed into the soil when in bloom. 



Liming e considered the first step in pond fertilization (Schaeperclaus, 

 1933; Jiesntr, 1937). Strictly speaking, it concerns the addition of caus- 

 tic liiae (quicklime, slaked lime, or calcium cyanamid (see Appendix A) to 

 the pond bottom when in spring fallow. Liming serves the following pur- 

 poses: 



1. Kills, by caustic or caustic and toxic action, the eggs and inter- 

 mediate stages of fish parasites and some plants. 



2. Raises the pH of water to a level most favorable for fish health 

 and metabolic cycles of the pond. 



3. Raises the A.C.C. of the water and creates a carbon-dioxide 

 reserve. 



Ii. Insures sufficient calcium for plant and animal nutrition; for 

 the building of carapaces and shells; and for the detoxification 

 of soluble sodium, magnesium, and potassium compounds. 



5. Ameliorates the bottom (aids mineral decomposition, liberates 

 potassium, hastens soil decomposition, lowers oxry-gen consumption). 



6. Eliminates strong excesses of putrescible organic matter (which 

 demand oxygen and provide favorable conditions for the existence 

 of many disease instigators). 



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