EXPERIMENT STATION BULLETINS. 509 



The immediate efBcieucy of limestoue depends in a large measure upon 

 the fineness of the particles and thorough incorporation with the soil 

 while that of marl depends upon its purity as well as thorough mixing 

 with the soil. Hydrated lime usually acts quickly in the soil. On 

 account of its greater solubility its incorporation with the soil mass is 

 not so essential, as it tends to move about in the soil with the soil 

 moisture. Especially is this the case with sandy soils and with the 

 larger applications. 



Although crops differ somewhat with respect to their lime require- 

 ments, it has been conclusively proved that if the soil is deficient in 

 lime the common crops with few exceptions, respond to its use. 



The margin of profit from normal applications of lime on so-called 

 acid soils is safe, as has been demonstrated by many experiment station 

 workers and farmers. 



The efficiency of stable manures and fertilizers is increased bv ample 

 quantities of lime in the soil, conversely, stable manure and fertilizers 

 increase that of lime. 



The most economical or best amount of lime to apply to a given soil 

 cannot be determined by laboratory methods, although its needs may 

 be indicated by several. Field trials should always be conducted when 

 one applies lime to the soil, this being nothing short of sound business 

 methods. 



Lime should be applied to the soil in the rotation as near as prac- 

 ticable to the crops that are most benefited b}' it especialh' if small 

 applications are made. This coupled with the fact that thorough mixing 

 with the soil is essential are the chief considerations in the application 

 of lime to the soil. In some cases it is ])rofitable to top dre.ss alfalfa. 

 Moreover, permanent meadows and pastures growing on soils deficient 

 in lime may be top dressed to advantage. 



CONCLI'STOX. 



In view of the low lime content of many ^lichigan soils the losses 

 entailed by leaching and by crops removed from the land and much 

 evidence that its u.se is profitable, every farmer should satisfy himself 

 by thorough field trials that his soil does or does not need this suJjstanx'e. 

 There are many indications that lime, by establishing alfalfa and clover, 

 as well as by its favorable effect on other crops is the most promising 

 single substance the farmer has at his disposal for soil improvement. 



Although many facts have been established concerning the liming of 

 soils it is unquestionably true that our knowledge of several phases is 

 meagre, especially is this true of sandy and muck soils. The question 

 as to the most economical fineness of grinding limestone is one that 

 cannot be satisfactorily answered. Moreover, the forms, fineness and 

 size of applications for different soil classes are worthy of serious con- 

 sideration. 



Finally, lime should be looked upon as only one of the conditions 

 involved in permanent systems of soil fertility. Since its presence in tlie 

 soil results in a somewhat more rapid decay of vegetable matter 

 precautions must be taken by means of crop rotation, turning under 

 crop residues and manure to maintain this substance which is so vital to 

 soil productivity. 



