24 BOARD OF AGRICULTURE. [Pub. Doc. 



In round numbers, we may say that a good crop, on well- 

 fertilized land, may take from it 100 pounds each of nitro-* 

 gen and of lime, 140 pounds of potash, scarcely any soda 

 or chlorine and less than 20 pounds of phosphoric acid ; 

 of sulphuric acid and magnesia, 20 and 30 pounds respec- 

 tively. 



These facts are instructive, and give us a valuable guide 

 in the use of fertilizers ; but let us not misinterpret them. 



In the first place, they do not show that a crop of 1,800 

 pounds of leaf tobacco must contain 140 pounds of potash 

 or 100 of nitrogen. A crop of 1,800 pounds of tobacco of 

 excellent quality may contain considerably less than these 

 amounts, and yet be of first-rate quality. A tobacco crop 

 will not take up just what it needs from the soil, and leave 

 the rest. Within certain limits, it will take up what it 

 finds, and often in excess of its wants. 



Thus, in our Poquonock experiments, where fertilizer- 

 nitrogen was put on in large excess of the probable crop 

 requirements, a much larger quantity of nitrates and some- 

 what more protein and nicotine were found in the leaf than 

 where less fertilizer-nitrogen was used. 



The largest percentage of potash was found in the tobacco 

 to which most fertilizer potash was applied. 



The same general fact was also true of magnesia and of 

 sulphuric acid, viz., the larger the supply in the soil, the 

 more went into the tobacco, and this excess did not, in any 

 way apparent, affect the quality of the crop. 



Hence these figures do not show the quantity of plant food 

 which a tobacco crop must have. They show that, j^ws the 

 excess which the abundantly fed plant will take up. 



To illustrate : your butchers' and grocers' bills, with what 

 food you take from the farm, show what your family has 

 eaten for the year. This table shows somewhat the same 

 regarding the tobacco crop . 



But you know that your housekeeping account does not 

 show what the members of your family needed to keep them 

 alive and well. They could have got on with less food, with 

 fewer appetizing things, which may be called luxuries, and 

 have been just as well for it at the year's end. The same is 

 true of the tobacco crop. Doubtless, with less potash, less 



