LIME OX SOILS 



BY JOIIX E. SMITH 



The various operations of tillage are performed for the pur- 

 pose of enabling the plant to obtain the food necessary in the 

 process of growth. Certain substances are sometimes added to 

 the soil to increase its productivity; these are known as soil 

 amendments and lime is one of the most useful of them. 



COERECTS THE ACIDITY 



An acid condition results from the decay of organic matter, 

 is brought to the top soil from the subsoil by capillary water, 

 is produced by nitrifying bacteria, and is formed in other ways. 

 All forms of lime (except gypsum) readily counteract or 

 neutralize this condition, one ton per acre in most cases being 

 sufficient to keep the soil neutral for two or three years. 



AIDS jN^ITRIFICATIOI^ 



The acidity of soils is somewhat injurious to the growth of 

 many plants and in many instances is fatal to the legumes 

 (clover, vetch, alfalfa, etc.), whose power to assimilate and 

 store nitrogen is dependent on the activity of bacteria that thrive 

 in a neutral or slightly alkaline soil but cannot live in the pres- 

 ence of much of the acidity which in part is the product of their 

 own work. A supply of lime in the soil neutralizes the acid as 

 rapidly as it is formed and thus prevents its accumulation and 

 maintains a condition favorable to the rapid growth of nitrify- 

 ing bacteria. Lime is therefore essential to the successful 

 growth of leguminous plants sooner or later. 



IMPROVES THE STRUCTURE 



By structure of the soil is meant the arrangement or grouping 

 of the soil particles. This is very intimately related to pore 

 space, water holding capacity, and to the movements of soil 

 moisture. 



The addition of lime to clay soils is a strong factor in pre- 

 venting cloddiness and in producing that most desirable granu- 

 lar, crumb-like structure which constitutes "good tilth," so 



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