LEGUMINOUS CROPS. Ill 



produced by the degradation of proteid ; the nitrogenous by- 

 products being for the most part, if not entirely, eliminated 

 from the body as waste matter. It is, however, now indubit- 

 ably established, at any rate in the case of the herbivora 

 which produce the most fat, that that substance is derived 

 largely, if not exclusively, from the non-nitrogenous constitu- 

 ents of the food — the carbohydrates. 



In the case of the supposed transformation in plants, the 

 same prodigal expenditure of the nitrogenous bodies in the 

 formation of the non- nitrogenous is, however, as has been 

 said, not involved. 



Effects of Nitrogenous Manures on Leguminous Crops. 



We have now to illustrate the influence of nitrogenous 

 manures on various leguminous crops which, as has been 

 pointed out, are characterised by containing a high percent- 

 age of nitrogen in their dry substance, and by assimilating a 

 large amount of nitrogen, from some source, over a given area 

 of land. It will be seen that the results bring to view some 

 very remarkable failures, but also some not less signal and 

 significant successes. 



Our first illustrations relate to experiments with beans, Effects of 

 grown for many years in succession on the same land, with- mtro 9 enous 



77hCL7lU7'&S 



out manure ; with a purely mineral manure (consisting of on beans. 

 superphosphate, and salts of potash, soda, and magnesia) ; 

 also with the same mineral manure, and nitrogenous manure 

 in addition, supplied either as ammonium-salts or as sodium- 

 nitrate. Table 35 (p. 112) gives a summary of the results 

 obtained under each of the three conditions as to manuring 

 over a period of 32 years of continued or interrupted experi- 

 ments, from 1847 to 1878 inclusive. The upper division 

 gives the average amount of total produce (corn and straw 

 together) per acre per annum, over each of the four 8-yearly 

 periods, and over the total period of 32 years. But, as there 

 were frequent failures of crop, the lower division of the table 

 gives the average produce per acre per annum over the years 

 of crop only during each period. 



Before referring to the figures, it should be explained that Nitrates 

 in the first 5 years the nitrogen applied to the third plot was ^° e r tj^ ct ' 

 in the form of ammonium-salts. The effects were, however, ammon- 

 so small and irregular, that the application of nitrogenous ium - sa Ms. 

 manure was then suspended for some years — indeed for 10 

 years ; after which, it having been observed that nitrates 

 were more beneficial to Leguminosae than ammonium-salts, 

 sodium -nitrate was applied instead; in amount supplying 

 86 lb. nitrogen per acre per annum, or nearly twice as much 



