26 ELEMENTARY AGRICULTURE 



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 read- 

 ily 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 soil of his farm 

 more easily soluble. 



Effect of Too Mitch Food, Plants may be killed 

 by too much food. Who has not seen spots of grass 

 killed out where the cattle have been salted or have 

 dropped manure? This is because the plants have 

 taken in too much solid food. Plants can live on so 

 small an amount as one part of solid food dissolved in 

 a million parts of water, and more than one part in a 

 thousand kills them. One way to kill noxious weeds 

 is to cover them with salt, lime, or ashes, so that they 

 will get more than one part of this food in every thou- 

 sand parts of water that they use. 



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 its plant food, and it will soon begin to show 

 evidence of being "worn out." Plant foods are being 

 continually used up by the growing plants, and re- 

 moved with them, and none are returned to take their 

 place. The heavier the crop the greater will be the 



