EFFECT OF LIME ON THE SOIL 



251 



about the same. In other words the farmer may apply 

 slaked lime, air-slaked lime, or ground carbonate in the form 

 of shell marl, oyster shells, or limestone, with equal results. 

 It is the bicarbonate of lime in any event which is the active 

 form in the soil. All that he must remember is that to get 

 100 pounds of calcium oxide he must use 100 pounds of 

 burnt lime, 130 pounds of slaked lime, or 180 pounds of 

 carbonate; of air-slaked lime he must know the calcium 

 oxide content. 











Fig. 63. — Lime and clover test. Check plat, yield of hay 980 pounds per 



acre. Pennsylvania Station. 



189. Effect of Lime on the Soil. — Inasmuch as lime is 

 for the most part a soil amendment, the changes which it 

 occasions in the soil, and by which plants are benefited, 

 are of great importance. No other element has such a great 

 variety of uses in crop production, and yet it must not be 

 considered a universal panacea for all soil ills. Figs. 63, 64, 

 65, and 66 show that while lime is needed to correct acidity, 

 fertilizers also are needed. 



(a) Neutralizing Acids. — This is perhaps the best known 

 function of lime, and the results are far reaching. Many 

 acids are poisonous to plants. That is, there is a direct 

 physiological effect, more particularly from the mineral 

 acids and from some organic acids, oxalic for example. Then 



