146 LESSONS IN AGRICULTURE 



Carbon 47.69 



Water 45.86 



93.55 Ibs. 



Sodium 09 



Magnesium 20 



Sulphuric acid 31 



Iron 04 



Chlorine 06 



Silica 2.75 



3.45 Ibs. 



Nitrogen 1.60 



Phosphoric acid 45 



Potash 66 



Lime 29 



3.00 Ibs. 



This table is interesting in that it shows that so 

 small a per cent of the composition of the plant is made 

 up of the nitrogen, phosphorus, potash and lime the 

 elements that exist in so small a proportion in the soil ; 

 yet it is this small proportion of these elements with 

 which the farmer must concern himself in intelligent 

 practice. 



Plant starvation. Now, if these foods are not found 

 in sufficient quantity in the soil, the plant grows slowly 

 and finally dies. Again, the soil may contain plenty of 

 plant food, but it may not be in a form readily soluble 

 by the water, and the plant suffers from a lack of food, 

 just as one may starve within ten feet of plenty of food 

 that is securely locked up so that he can not get at it. 

 One problem which the farmer is called upon to solve 

 is, how to make the plant food in the soil of his farm 

 more easily soluble. 



Soil exhaustion. From what we have learned it is 

 clear that, if the farmer raises grain on his farm, to sell, 

 and never returns manure to the soil, he will rob it of 



