348 HANDY-BOOK OF HUSBANDRY. 



Lime 300 



Magnesia 85 



Potasli 200 



Soda, chloride of sodium, oxide of iron, sand, loss, etc 87 



*■'■ Let us suppose the land to have yielded 4 tons of clover-hay 

 per acre. According to the preceding data we find that such a 

 crop includes 224 lbs. of nitrogen, equal to 272 lbs. of ammonia, 

 and 672 lbs. of mineral matter or ash constituents. 



'' In 672 lbs. of clover-ash we find — 



Phosphoric acid 51^ lbs. 



Sulphuric acid 29 " 



Carbonic acid 1 i i " 



Silica 20 " 



Lime -. 201 « 



Magnesia 57 " 



Potash , 134* " 



Soda, cliloride of sodium, oxide of iron, sand, etc 58 " 



672 lbs. 



" Four tons of clover-hay, the produce of one acre, thus con- 

 tain a large amount of nitrogen, and remove from the soil an enor- 

 mous quantity of mineral matters, abounding in lime and potash, 

 and containing, also, a good deal of phosphoric acid. 



" Leaving, for a moment, the question untouched, whether the 

 nitrogen contained in the clover is derived from the soil or from 

 the atmosphere, or partly from the one and partly from the other, 

 no question can arise as to the original source from which the 

 mineral matter in the clover-produce is derived. In relation, 

 therefore, to the ash-constituents, clover must be regarded as one 

 of the most exhausting crops usually cultivated in this country. 

 This appears strikingly to be the case when we compare the pre- 

 ceding figures with the quantity of mineral matters which an 

 average crop of wheat removes from an acre of land. 



'' The grain and straw of wheat contain, in round numbers, in 

 100 parts : — 



Water 



♦Nitrogenous substances (flesh-forming matters). 



Non-nitrogenous substances 



Mineral matter (ash) 



• Containing nitrogen. 



