122 EXPERIMENT STATION RECORD. 



lime was not cliaiiged in any respect. With nitrate of ammonia none 

 of the nitric nitrogen, but a <;oiisiderable proportion of the ammoniacal 

 mtrogen was tixed, and tlie final solution appeared to contain a mix- 

 ture of nitrate of ammonia and nitrate of lime. The soil fixed a con- 

 siderable proi)ortion of the potash of carbonate of potash, and it was 

 replaced to some extent by lime. Carbonate of soda was but slightly 

 changed by contact with the soil. With the solution of bicarbonate of 

 lime an ai)preciable amount of potash and a considerable excess of lime 

 were removed from the soil. Carbonate of ammonia appeared to be 

 retained by the soil without undergoing any transformation. 



Practical deductions regarding the use of fertilizers. — As regards the 

 bearing of chemical analysis on the use of fertilizers on soils, it is stated 

 that while no fixed rules can be laid down, it apijears that a soil which 

 contains less than 5 x)er cent of carbonate of lime and more than GO 

 "degrees" of clay would be benefited by an application of lime. The 

 amount of lime applied should vary with the proportion of clay. Soils 

 rich in humus shouhl l)e liberally limed, and in peaty soils this substance 

 is absolutely necessary to productiveness. The use of sulphate of iron 

 to render lime soluble is also suggested, but this substance should be 

 used only on soils comparatively rich in lime. 



Soils containing less than 0.1 per cent, or 4,000 kg. per hectare, of 

 phosphoric acid, as indicated by the experiments of Deherain, Joulie, 

 Dellisse, and the author, will probably be benefited by applications of 

 phosphates; but, as pointed out by Milntz, this limit should not be con- 

 sidered fixed, depending largely upon the assimilability of the phos- 

 phoric acid in the soil. As to the form in which the phosphate should 

 be applied, it is stated that if the soil is calcareous superphosphates may 

 be used with advantage. If, however, the soil contains less than 1 per 

 cent of lime, suf>erphosphates are likely to be injurious, and a phosphate 

 containing free lime, such as Thomas slag, should be used. Precipi- 

 tated phosphates are well adapted to all soils which need phosphoric 

 acid, but ai^pear to produce best results on those which contain small 

 amounts of lime. The natural iihosphates are used to best advantage 

 on humus soils, and should be applied only in fine ground condition. 



In regard to the use of potash, less definite statements can be made 

 than respecting phosphoric acid. The author's investigations indicate 

 that 0.25 per cent, or 10,000 kg. per hectare, is the limit, above which 

 applications of potash salts will not prove profitable. It appears that 

 plants have especial power of assimilating potash in insoluble forms, 

 and that therefore it is not always necessary to supply this element in 

 the form of soluble salts. 



The normal proportion of nitrogen in good soils is stated to be about 

 0.1 i)er cent, or 4,000 kg. per hectare. Whether soils containing this 

 proportion of nitrogen will be benefited by applications of nitrogenous 

 fertilizers will be determined largely by the condition of the nitrogen in 

 the soil and the demands of the plant cultivated. This figure is given 



