Ground mineral phosphate

Up to 70% of nitrogen in soluble nitrogen fertihsers (e.g. ammonium nitrate and some other compounds) is used in the first year. For phosphate in soluble form, e g. triple superphosphate and compounds containing phosphate, allow two-thirds after one crop, one-third after two and one-sixth after three crops. For phosphate in insolnble form, e.g. bone meal and ground mineral phosphate, allow one-third after one crop, one-sixth after two and one-twelfth after three. For potash, e.g. muriate or sulphate of potash and compounds containing potash, allow a half after one crop and a quarter after two crops. For lime one eighth of the cost is subtracted each year after application. 

Mineral Feed. Mineral feed supplements for domestic animals and fowl usually contain a pure form of pulverized limestone. In fact, some state laws require the supplement to be at least 35% available calcium. Other sources of calcium are bone meal and dicalcium phosphate. Use as mineral feed has been a steadily growing market for limestone. The material is ground to 90% minus 0.15 mm (100 mesh) or 80% minus 0.9074 mm (200 mesh), is low in silica, and has strict tolerances on arsenic and fluorine (see Feeds and feed additives). 

Dissolved mineral salts The principal ions found in water are calcium, magnesium, sodium, bicarbonate, sulphate, chloride and nitrate. A few parts per million of iron or manganese may sometimes be present and there may be traces of potassium salts, whose behaviour is very similar to that of sodium salts. From the corrosion point of view the small quantities of other acid radicals present, e.g. nitrite, phosphate, iodide, bromide and fluoride, have little significance. Larger concentrations of some of these ions, notably nitrite and phosphate, may act as corrosion inhibitors, but the small quantities present in natural waters will have little effect. Some of the minor constituents have other beneficial or harmful effects, e.g. there is an optimum concentration of fluoride for control of dental caries and very low iodide or high nitrate concentrations are objectionable on medical grounds. 

As discussed earlier in Section 3.17, the excessive application of arsenic-bearing pesticides and phosphate fertilizers on agricultural lands, golf courses, and lawns may locally contaminate surface waters and ground-waters (Welch et al., 2000), (Lewis et al., 2002), 590. Phosphates desorb arsenic from mineral surfaces and readily interfere with the sorption and coprecipitation of arsenic onto iron (oxy)(hydr)oxides (Campos, 2002). Commercial phosphate fertilizers also frequently contain >13 mg kg-1 of arsenic impurities (Campos, 2002), which may further contribute to groundwater contamination. 

Phosphorus (0.11% of the lithosphere) is found mainly in minerals based on calcium phosphate, collophanite, the monohydrate, Ca3(P04)2.H20, and apatite, CagF(P04)3. About 90% of the phosphate rock mined is converted into fertilisers, the rest is used for making elementary phosphorus, phosphorus compounds and such alloys as phosphor bronze. For fertilisers rock phosphate is finely ground and treated with sufficient concentrated sulphuric acid to convert it to the soluble dihydrogen phosphate ... 

Ground shelled corn Salt, trace mineralized Cottonseed meal (41%) Defluorinated phosphate Cane molasses... 

Ground shelled com Cottonseed meal (41%) Coastal hay or oak sawdust Salt, trace mineralized Defluorinated phosphate Vitamin A Vitamin D Aureomycin... 

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