HATCHERY OPERATIONS 



99 



Table 13. sources of p^o, in commercial phosphate fertilizers 



SOURCE MATERIAL 



CHEMICAL FORMULA 



' P;0-, 



AVAILABILTIY 



Ammonium 

 metaphosphate 



Basic slag 



Bone meal 



Calcium 



metaphosphate 



Defluorinated 

 rock 



Diammonium 

 phosphate 



Enriched 



superphosphate 



Monoammonium 

 phosphate 



Potassium 



metaphosphate 



Rock phosphate 



Triple 



(NHjaPO., 

 (CaO-P^ySiO.^ 



Ca(P03)2 

 CalPOj^ 



(NHjaHPO^ 



Ca(H,P04), 



NH^H^PO, 



Ordinary Ca(H^P04)^ 



superphosphate 



Phosphoric acid H3PO4 



KPO. 



(Ca3(P04),)3-CaF, 



(Ca(H,P04),)3 



15 

 60-65 



73 Variable solubility; has 



17"" nitrogen 



9 Poor in calcium-rich 



waters 



Not readily available 



Equal to superphosphate 

 in acid and neutral soil 



41.3 Used primarily in live- 



stock feeds; insoluble 

 in water 



53 Completely water solu- 



ble has 21" nitrogen 



32 About the same as ordi- 



nary superphosphate 



48 CompleteH water- 



soluble in form of 

 ammophosphate; has 

 1 1" I nitrogen 



18-20 Not completely water- 



soluble 



72.5 Water-soluble and acid 



in reaction 



55-58 Equal to or superior to 



ordinary superphos- 

 phate; has 35-38','u 



32 Least soluble of calcium 



salts; availability var- 

 ies from to 15"» 



44-51 A major portion is 



water-soluble 



Phosphorus will not exist for long in pondwater solution. Although both 

 plants and animals remove appreciable amounts of the added phosphate, 

 the majority of applied phosphorus eventually collects in the bottom mud. 

 Here, phosphorus may be bound in insoluble compounds that are per- 

 manently unavailable to plants. Some 90-95% of the phosphorus applied to 

 field crops in fertilizers becomes bound to the soil, and the same may hold 

 true in ponds. 



