188 SOILS AND FERTILIZERS 



247. Amount of Lime Removed in Crops. 38 



Pounds per acre. 



Wheat, 20 bushels i 



Straw, 2000 pounds 7 



Total 8 



Corn, 65 bushels i 



Stalks, 3000 pounds i [ 



Total 12 



Peas, 30 bushels 4 



Straw, 3500 pounds 71 



Total 75 



Flax, 15 bushels 3 



Straw, 1800 pounds . 13 



Total 16 



Clover, 4000 pounds 75 



Clover and peas remove so much lime from the soil 

 that they are often called lime plants. The amount 

 required by grain and hay is small compared with that 

 required by a clover or pea crop. 



248. Amount of Lime in Soils. There is no other 

 element in the soil in such variable amounts as cal- 

 cium. It may be present from a few hundredths of a 

 per cent, to tw r enty per cent, or more. Soils which 

 contain from 0.4 to 0.5 per cent, of lime as carbonate 

 are usually well supplied. The lime in a soil takes 

 an important part in soil fertility ; when deficient, 

 humic acid may be formed, nitrification checked, and 

 the soil particles will lack binding material. 



249. Different Kinds of Lime Fertilizers. By the 



term 'lime fertilizer' is usually meant land plaster 

 (CaSO 4 ,2H 2 O). Occasionally quicklime (CaO) and 



