Sick Soils not Influenced by Parasites 27 



guid condition of the growing crop. Sorrels, poverty 

 grass, broomsedge, cinquefoil, and redtop thrive 

 best, and are generally indicative of acid soils. Not 

 all truck crops are equally sensitive to soil acidity. 

 Hartwell and Damon J have determined the degree in 

 which truck crops are benefited by the application of 

 lime to an acid soil. As a guide to the effect of lime 

 on crops, those which seem to benefit most are in- 

 dicated by the number (3), lesser degrees of improve- 

 ment are indicated by the numbers (2) and (i). 

 Crops which tolerate a moderate amount of acidity 

 are followed by the figure (o) , and those which thrive 

 best without lime by ( i) : Asparagus (3), beans (o), 

 beets (3), cabbage (2), carrots (i), cauliflower (2), 

 celery (3), chard (2), chicory (o), cowpea (o), cress 

 (o), cucumber (i), eggplant (2), endive (3), okra (3), 

 horseradish (2), kale (i), kohlrabi (i), leek (3), lettuce 

 (3), mustard (2), muskmelon (o), onion (3), parsley (o), 

 parsnip (3), pea, garden (i), pepper (3), potato (o), 

 radish (i), rape (2), rhubarb (3), sorrel ( - 1), spinach 

 (3) (fig- 4& to h), turnip (o), watermelon ( i). 



Treatment of Acid Soils. The best remedy known 

 is lime. Its effect is to neutralize the acidity, 

 restoring the normal equilibrium for the activity of 

 the soil flora, and thus enabling the plant to flourish. 

 The amount of lime to be used depends largely on 

 the kind of soil and the degree of its acidity. Ac- 

 cording to Blair 2 a loamy to a clay loam will require 



1 Hartwell, B. L., and Damon, S. C., Rhode Island Agr. Expt. 

 Sta. Bui., 160: 408-446, 1914. 



"Blair, A. W., New Jersey Agr. Expt. Sta. Cir., 54: 3-11, 1916. 



