FERTILIZERS. 



951 



FERTILIZERS. 



Culture trials with precipitated calcium phosphate, II, ^i. G. Souekbaum 



{Medd. K. Lavdth. Ahid. Exptlfalt. [Slockliohit], IHOJ, No. 75, pp. U).— The trials 

 here reported are continuations of tliose conducted dnring the snnimer of 1900 

 (E.S. E., i;^, p. 836). The general plan of the trials was to asciertain the fertilizer value 

 of tricalcium orthophosphate ])repared from apatite throngh electrolysis, as coin])are<l 

 with other j)hos])hatic materials. The new series of trials Avere conducted during 1!»01 

 with 5 different iihosithatic fertilizers, viz.: (1) Tricalcium phosphate prepared from 

 "apatite concentrate," with sodium chlorate as electrolyte, and dried at 80° C. It 

 contained 47.09 per cent lime, 0.76 per cent potash, and 34.30 per cent phosphoric 

 acid, 28.38 per cent of phosphoric acid solnhle in 2 per cent citric-acid solution, and 

 5.60 per cent soluble in Petermann's ammonium-citrate solution. (2) Dicalcium 

 phosi:)hate, prepared electrolytically (with sodium chlorate) from so-called "slig" 

 (apatite, iron ore, etc.). It contained lime 38.53 per cent, phosphoric acid 39.91 per 

 cent, citric-acid soluble phosphoric acid 37.23 per cent, and citrate-soluble phosphoric 

 acid (Petermann's solution) 33.52 per cent. (3) Precipitated i)hosphate, essentially 

 a mixture of dicalcium and tricalcium phosphates, with 41.36 percent total and 24.12 

 per cent citrate-soluble phosphoric acid. (4) Steamed bone meal, containing 21.39 

 per cent total and 20.27 per cent citric-acid soluble phosphoric acid, with 4 per cent 

 nitrogen. (5) Superphosphate (same as used in the first series) containing 17.6 per 

 cent water-soluble phosphoric acid. 



The field used for the experiments was a poor sandy soil, with 0.336 i)er cent lime, 

 0.025 per cent potash, and 0.039 per cent i>liosplioric acid (soluble in hot hydrochloric 

 acid of sp. gr. 1.15). In order to further investigate the comparative effect of the 

 different phosphates with or without an extra supply of lime in the soil (E. S. K., 

 12, p. 323), aijplications of similar amounts of the different fertilizers were always 

 made in duplicate, one series receiving lime and the other no lime. The crop used 

 was oats, which were sown in glass cylinders, 49 cm. high and 24 cm. in diameter. The 

 basal fertilization applied was at the rate of 300 kg. of potash, 100 kg. of nitrogen, and 

 33 kg. each of connnon salt and magnesium sulphate per hectare. The precipitated, 

 dicalcic phosphates and superphosphate were added hi three different (puintities, 

 viz, at the rate of 50, 100, and 150 kg. of citrate or water-soluble phosphoric acid, and 

 the other phosphates at the rate of 100 kg. of phosphoric acid per hectare. Six 

 parallel tests were made with each fertilization, of which 3 were made with lime 

 (333 kg. of calcium carbonate in the form of finely powdered marl)le per hectare), 

 and 3 without lime. 



The results obtained showed that the liming in itself, without accompanying addi- 

 tion of phosphoric acid, produced a considerable increase in yield— on the average 

 for all series, 100:163.1. The following statement presents the main average results 

 of the trials, taking the results on the "no phosphoric acid" and "no lime" plats 

 as 100: 



Comparative rffrf (>/ diferait pluixphateit, with and vMumt /line, mi. natx. 



N(j jiliosplioric acid 



50 kg. of iili(is|ih(iric acid por hoctare in superphospliate 



100 ka. of phos]ihiiric acid per licctare in siipcrpliosphate 



150 kg. (if pli(i.s].li(iri(' iii'i<l per licctare in snpcrplidsphatc 



50 kg, (if iiliosplKinc acid per licctare in dicidcinm plidsphatc 



100 kK. of phosplioric acid per licctare in dicalciuiii plios|ihat.c 



150 kf,'. of phosphoric acid per hectare in dicalcium phosphate 



100 kK. of phosphoric acid per hectare in iirecipitate 



100 kg. of ]ihosphoric acid ]ier hectare in tricalcium phosphate ... 

 100 kg. of phosplioric acid per hectare in bone meal 



163 

 101.3 

 102.3 

 97.9 

 90.7 

 97.7 

 101.6 

 100.2 

 33.4 

 18.7 



