36 PLANT PRODUCTS 



Such mixtures as are here being described are very rarely 

 suitable for top dressing. They are best, therefore, applied 

 in the drill either with or without farmyard manure. 

 Containing a variety of ingredients, they are in many respects 

 safer, since even if the user possesses the knowledge to apjjly 

 crude fertilizers, he still is at the mercy of the weather, 

 and it is not possible to predict exactly which of the crude 

 fertilizers would be the best to apply. A mixture which 

 contains a variety is much more likely to apply at least 

 something that is necessary (see Introduction) . 



REFERENCES TO SECTION II 



Collins and Hall, " The Inter-relationships between the Constituents 

 of Basic Slag," Journ. Soc. Chem. Ind., 1915, p. 526. 



Robertson, " The Influence of Fluorspar on the SolubiHty of Basic 

 Slag in Citric Acid," Journ. Soc. Chem. Ind., 1916, p. 216. 



Bernard Dyer, " Available Mineral Plant Food," Journ. Chem. Soc, 

 1894. p. 115. 



Hughes, Journ. Soc. Chem. Ind., 1901, p. 325. 



Robertson, " Notes on the Nature of the Phosphates contained in 

 Mineral Phosphates," Journ. Agric. Science, 8, p. 17. 



Robertson, " Solubility of Mineral Phosphates in Citric Acid," Journ. 

 Soc. Chem. Ind., 1916, p. 217. 



Bennett, "Animal Proteids." 



Jones, "The Wagner Test as a Measure of the Availability of the 

 Phosphate in Basic Slag," Journ. Board Agric, 1914-15, p. 201. 



Davis, "The Phosphate Depletion of Soils of Bihar," Agric. Journ. 

 Ind., 1917, p. 181. 



Jatindra Nath Sen, " The Influence of the Presence of Calcium 

 Carbonate on the Determination of Available Phosphoric Acid in Soils by 

 Dyer's Method," Agric. Journ. Ind., 1917, p. 258. 



