140 THE CHEMISTRY OF THE FARM 



phosphate in addition to the dung, the albuminoid 

 nitrogen was only 29 per cent, of the total. It is 

 evident, therefore, that the large mangels or turnips, 

 produced by very liberal manuring, are less nutritious 

 than smaller roots. At the same time, it must not 

 be forgotten that the total amount of food produced 

 per acre is much greater under liberal manuring. 

 Potatoes, unlike mangels, deteriorate but little in 

 quality as they increase in size. Turnips grown with 

 superphosphate alone on exhausted land are deficient 

 in nitrogenous constituents. 



In the case of hay the composition is further affected 

 by the conditions of hay -making ^ and by the subsequent 

 changes in the rick. Hay that has suffered from rain 

 during hay-making will contain less soluble matter 

 (carbohydrates and albuminoids) than well-made hay ; 

 this loss will be greatly increased if the hay has been 

 long in the field, and undergone fermentation as well 

 as washing. The changes which take place in the 

 rick are seen on a larger scale in the process of 

 ensilage. 



When green fodder is stored in a silo the mass 

 becomes hot from fermentation, a loss both of water 

 and solid matter takes place, carbonic acid and othei 

 gases being evolved. If the green fodder has been cut 

 small, and compressed by weights as soon as it was 

 placed in the silo, oxidation is at a minimum ; under 

 these circumstances, alcoholic, lactic, and butyric 

 fermentation sets in more or less strongly, and " sour 

 silage " is produced. If, on the other hand, the silo is 

 filled gradually, and a few days elapse before the 

 weights are applied, the temperature rises much 

 higher, owing to the greater bulk of air enclosed. 



