380 AGRICULTURE OP MAINE. 



which would prevent the planting of untreated *'seed" potatoes. 



The only economic recourse, if a soil is favorable to scab, is 

 to use properly compound acid fertilizers. Flowers of sulphur 

 will accomplish the same result, but they do not at the same 

 time fulhl the other functions of the complete fertilizer. li 

 flowers of sulphur are used, the *'seed" tubers, when cut ready 

 for planting, should be rolled in them, and sulphur may also be 

 scattered in the drills in quantities ranging from 300 to 600 lbs. 

 to the acre. Another drawback to the sulphur treatment is the 

 extra cost of the material, which is a serious item, particularly 

 in a year when the "bottom drops out" of the potato market. 



If you ask what the effect of liming will be on the powdery 

 scab, I regret that I cannot answer. This is a point which your 

 experiment station is no doubt studying, and concerning which 

 it can soon inform you. It is to be hoped that highly acidic 

 conditions are also destructive to the powdery scab germs, for 

 if they thrive best in very acid soils the potato industry will 

 surely soon be between Scylla and Charybdis, unless the greatest 

 precautions are taken. 



SOME INDIRECT CHEMICAL EFFECTS OF LIME IN SOILS. 



Much has been written recently in the agricultural press con- 

 cerning the ability of lime to liberate potash from soils. Some 

 of these statements have been moderate, whereas many have 

 been much overdrawn. It is no doubt true that where soils have 

 been fertilized generously with potash in recent years, the use 

 of lime will add noticeably, for a time, to the quantities of 

 potash which plants can take from the soil. This is due to 

 the fact that lime enters certain compounds replacing potash, 

 which then passes into solution in the soil water or is held 

 in the soil in such a physical state as to be more readily 

 available than before. It is obvious that an end to such a possi- 

 bility will soon be reached, for there will not be sufficient potash 

 remaining in these readily decomposable compounds to be lib- 

 erated to any practical extent, surely without such excessive 

 liming as would be uneconomic and wholly unwise for various 

 reasons. 



Furthermore, most of the potash in soils is present in such 

 combinations that lime would have no practical decomposing 

 effect upon it. In my earlier experiments on a soil of granitic 



