160 BOARD OF AGRICULTURE. 



The qiiantit}' of potash removed in potatoes is very large. Ii the 

 four huiulietl biisliels it amounts to about one hundred thirty pounds. 

 Compare this with the amount removed by animals. An ox, weigh- 

 inj]: 1400 pounds, which was killed for the purpose of analysis, con- 

 tained only two and one-half pounds in the wliole carcass and otfal. 

 Hay is another crop which takes a good deal of potash from the soil, 

 and farmers in England rarely grow either hay or potatoes for sale 

 unless there are facilities for the purchase of town dung. Artificial 

 manures are certainly not used alone b\' practical farmers in the 

 growth of their crops. 



We always, however, obtain a larger crop of potatoes where we 

 apply the mineral manures (potash and phosphoric acid) alone than 

 where we apply the nitrogen without the minerals. This is shown by 

 the following table, which gives the yield per acre (in pounds) on 

 each of the five plots 188^, being the ninth in succession without 

 any change in the quantities or kinds of manures ; their chemical 

 composition is also stated : 



Plot. Fertilizer. Yield in lbs. 



1. 14 tons of dung 13,440 



2. Minerals without nitrogen, 11,201 



3. Nitrogen without minerals, 7,020 



4. Minerals and ammonia.... 19,820 



5. Minerals and nitrates .... 18,120 



The character of the manure is most clearly shown in the com- 

 position of the crop. In No. 2, manured with minerals, the minerals 

 are five times as high as the nitrogen ; while in No. 3, where ammo- 

 nia or nitrates are used, the minerals are considerably less than 

 double the amount of nitrogen. In both cases there is a waste of 

 power, shown by small crops and unused manures. The loss, how- 

 ever, is not equal in both cases, as the minerals remain in the soil to 

 be taken up at some future time, while the nitrogen is probably lost. 



