»4 ANNLAL REPORT OF THE Mft. Doc. 



Phosphorite should not be applied to light soils i^probably not to 

 any soil long cultivated) for cereals, but only for bnckvs-heat. mus- 

 tard, lupens and peas. In the case of peat or muck land, however, 

 and acid soils generally, phosphorite may be applied for any crop. 

 An experiment on black soil is recorded in which, without manure. 

 buckwheat gave more produce than wheat; the addition of phos- 

 phorite and of sodium di-hydrogen phosphate greatly increased the 

 yield of wheat bat not of buckwheat. This is attributed to the 

 ability of buckwheat to make use of sparingly soluble phosphoric 

 acid. Experiments are also described upon the use of various am- 

 monium salts in conjunction with the phosphates, and the results 

 showed that they acted as solvents and made the phosphoric acid 

 available. 



THE USE OF FHOSPORITE AXD GREEN MANURING. 



Some experiments on this subject were conducted by A. X. Engel- 

 hardt. which are abstracted in Chem. Centralblat. 1901. p. 232. 

 The follov^-ing were the results obtained from three year's field ex- 

 periments: The fine-ground untreated phosphate was especially ef- 

 fective on cereals. The effects was best on soils containing an 

 abundance of organic matter. The finer the meal and the greater 

 the percentage of phosphate of lime the more effective was the phos- 

 phate. The best results were obtained with rye. but the following 

 crop of oats was also benefited. When the phosphorite was ap- 

 plied to rye. oats or flax, and these crops followed by a crop of rye. 

 to which barnyard manure was applied, the yield of the latter was 

 much better than of rye which had received only an application of 

 barnyard manure. 



The results showed that ground phosphorite can be profitably used 

 to supply phosphoric acid on soilswhich contain a sufficient amounr 

 of nitrogen, potash and lime. When its action lessens, green manur 

 ing should be resorted to. Lime and marl used in conjunction with 

 the phosphorite was advantageous. 



CONCLUSION. 



In conclusion, it mav be said that there are manv more experi- 

 ments that might be referred to which have covered the same points 

 alreadv considered, and manv others which have had to do with 

 particular phosphates, but that it is needless to go over them in 

 detail as the results are. in most instances, practically the same as 

 those already cited and are simply confirmatory of the statements 

 which have been made from time to time in this article. 



The experiments which have been quoted from show that many 

 of the popular notions regarding phosphates are not fully warranted 



