CLOVER AS A PREPARATORY CROP FOR WHEAT. 4.QI 



Carbonic acid .' 18 



Silica 3.0 



Lime 30.0 



Magnesia 8.5 



Potash 20.0 



Soda, chloride of sodium, oxido of iron, sand, loss, &o 8.7 



100.0 



Let US suppose the land to have yielded four 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 5 1 ^ lbs. 



Sulphuric acid . . 29 " 



Carbonic acid 121 " 



Silica 20 " 



Lime 201 " 



Magnesia 57 " 



Potash 134^ " 



Soda, chloride of sodium, oxide of iron, saud, Ac 58 " 



672 lbs. 



Four tons of clover hay, the produce of one acre, thus contain 

 a large amount of nitrogen, and remove from the soil an enormous 

 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 matters 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 : 



Grain of Wheat. Straw. 



Water 15.0 16.0 



*Nitrogenou3 substances (flesh-forming matters) ....11.1 4.0 



Non-nitrogenous substances 72.2 74.9 



Mineral matter (ash) 1.7 5.1 



100.0 100.0 



* Containing nitrogen 1.78 .64 



