612 MISCELLANEOUS FARM. SUBJECTS 



INFLUENCE OF LIME UPON SOME PLANT DISEASES. 



Potato Scab. It has been shown that carbonate of lime and 

 such other compounds of lime as are changed into the carbonate by 

 decomposition within the soil all tend to favor the production of 

 potato scab, provided the germs of the disease are already in the soil 

 or are introduced into it on the seed tubers. This seems to be due 

 to the fact that the lime makes the soil alkaline or to some influence 

 which the combined carbonic acid of the carbonate of lime exerts 

 upon the development of the fungus. In view of this unfavorable 

 action of lime caution should be observed in liming potato fields. 



Club Root. Many writers seem to agree that liming is capable 

 of lessening materially the injury to turnips, cabbages, etc., caused 

 by the disease known as "finger-and-toe" and "club root." English 

 writers assert that by resort to liming excellent crops of turnips 

 have been produced where without it the crop was a failure, owing 

 to the attacks of the disease. 



Other Diseases. The effect of different compounds of lime has 

 been tested, with not entirely conclusive results, on various other 

 diseases, including cranberry and sweet potato diseases, and a root 

 disease of alfalfa (Rhizoctonia medicaginis) . Slaked lime was found 

 to be effective in reducing soil rot of sweet potatoes, and quicklime 

 in checking or preventing the root disease of alfalfa. 



How Often Should Liming Be Practiced? The frequency with 

 which liming should be practiced depends upon several conditions; 

 for example, upon the character of the soil, the quantity of lime 

 employed in each application, the number of years involved in a 

 rotation, the plants to be grown and their order of succession. For- 

 merly, in England, large quantities of lime were applied at some- 

 what rare intervals, but there and elsewhere at the present time the 

 preferable practice seems to be to use small amounts and apply it 

 more frequently. As a general rule it may be stated that from half 

 a ton to one and a half tons of lime per acre applied every five to 

 six years is sufficient. There may exist extreme soils requiring 

 either more or less than these amounts. If soils which are quite 

 acid and have not previously been limed are to be seeded, with the 

 intention of allowing them to remain in grass for several years, as 

 much as two or three tons of lime per acre may sometimes be ad- 

 visable. Only very extreme cases would call for larger applications. 

 If in a rotation covering a considerable number of years two crops 

 especially benefited by lime are introduced at about equidistant in- 

 tervals of time, it may be advisable to lime twice in the course of the 

 rotation, each time just prior to their introduction. In renovating 

 acid pastures and meadows it is usually preferable to apply a fair 

 amount of lime upon the furrows when they are first plowed, so 

 that this may be thoroughly mixed with the soil by subsequent plow- 

 ing and harrowing, and just prior to seeding to grass make another 

 generous application. By such treatment, provided the other essen- 

 tial fertilizing ingredients are employed, a good stand of clover, 

 Kentucky bluegrass, timothy, and other grasses may be obtained 

 where in many instances they were formerly partial or total failures 



