1906.] Manurial Effect of Bone-Meal. 



74i 



such as superphosphate, was added, the mixed nitrate of 

 soda and sulphate of ammonia manure was found to act some- 

 what differently, and indicated that the addition of nitrogen, in 

 the form of ammonia, resulted in a proportionately decreased 

 yield. 



It seemed from this that the simultaneous presence of two 

 or more different forms of nitrogen was advantageous in 

 enabling certain phosphates, namely, those difficult of assimila- 

 tion, to produce their full effect, and Professor Soderbaum's 

 experiments show that bone-meal, in the presence of salts of 

 ammonia or organic combinations of nitrogen, yielded, without 

 exception, larger crops than when the nitrogenous manures 

 consisted exclusively of nitrate of soda. This was found to be 

 also the case with Algerian phosphate and precipitated tricalcic 

 phosphate. 



This increased yield occurred both with mixed manures of 

 nitrate of soda and sulphate of ammonia, and also with 

 ammonia alone. Indeed, in the latter case the crop reached its 

 maximum. 



The yield of grain was increased throughout to a greater 

 extent than that of straw, particularly in those cases where the 

 manuring was carried out with organic combinations of nitrogen. 



The increased crop produced by the addition of ammonia 

 varied, within fairly wide limits, from year to year, according 

 to the various meteorological conditions. 



In favourable cases the total crop after bone-meal was more 

 than doubled, and the grain crop nearly trebled. 



With superphosphate, basic slag, and precipitated dicalcic 

 phosphate, the employment of ammonia led to no increased 

 yield ; rather, in individual instances, to an unimportant 

 diminution in the crop. 



When employed on soils free from large quantities of lime, 

 bone-meal may be expected to have as great an effect in 

 respect to its phosphoric acid as superphosphate, provided that 

 salts of ammonia are present at the same time. 



It may be pointed out that the above results exclusively refer 

 to the experimental conditions ; whether and to what extent 

 they are of general application will form the subject of further 

 experiments. — [Deutsche Landw. Presse, Jan., 1906.) 



