ORGANIC NITROGEN FERTILIZERS 



109 



The seed is often roasted in a pot and pounded in a 

 mortar with about four times its volume of water, which 

 is kept boiling. The mixture is constantly stirred with 

 a large wooden spoon and the oil skimmed off the surface. 

 This process only gives a wet sludge instead of a cake, which, 

 although it can be used localty as a manure, is of no use for 

 export. The seed is sometimes soaked overnight in water, 

 and then ground up with an ordinary pestle and mortar 

 type of mill, the oil escaping through a hole in .the mortar. 

 The hole is easily choked by pieces of cake and needs con- 

 stant cleaning with a stick. This method is generally 

 considered to give the best fertilizing cake for local purposes. 

 Considerable quantities are also sent from the local growing 

 centres down to pressing mills in the large ports, where 

 cakes similar to those produced in this country are obtained. 

 Castor cake, having been obtained by any of these processes, 

 is frequently milled and sold as castor meal. When finely 

 divided it is much more suitable for application to the 

 land. 



TABLE 12. 



Rape Cake, Rape Dust and Rape Meal. These manures 

 are manufactured from brassica napus, the oil being expressed 

 in crushers as for other oil seeds. Most of the rape seed comes 

 from Russia, Germany, Austria-Hungary and India; in 

 India there are two varieties grown, white and brown seed. 

 Rape seed contains about 40 % of oil, and the manufactured 

 cake frequently has 9 % left in it. Most of the rape cake 

 manufactured is used for manure ; although pure rape 



