﻿BULLETIN OF THE 



No. 6 



Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief. 5 

 September 19, 1913. 



THE AGRICULTURAL UTILIZATION OF ACID LANDS 

 BY MEANS OF ACID-TOLERANT CROPS. 



By Frederick V. Coville, 

 Botanist in Charge of Economic and Systematic Botany. 



INTRODUCTION. 



In the past 20 years farmers have witnessed the development of 

 what may be called a lime-and-clover literature and the growth of a 

 corresponding agricultural practice. The scientific researches of 

 various investigators published from 1867 to 1888 had demon- 

 strated that leguminous plants through the bacteria of their root 

 tubercles were able to take nitrogen from the atmosphere and that 

 when a crop of these plants was plowed under the land was enriched 

 as if by a corresponding application of manure. 



In the northeastern United States the principal leguminous plant 

 used in crop rotations had been red clover. The scientific con- 

 firmation of the popular belief that this plant had high value as a 

 green manure greatly stimulated its use, the customary procedure 

 being to plow under the clover turf after taking off one or two cut- 

 tings for hay. It was found, however, that if the land is acid in 

 its chemical reaction red clover makes but feeble growth. If the 

 chemical reaction is neutral or slightly alkaline and other conditions 

 are favorable, heavy crops of red clover are produced. This con- 

 sideration greatly extended the practice of applying lime, in order 

 to neutralize the acidity of the soil and thus increase the manurial 

 use of clover in crop rotations, over large areas of the older lands 

 of the eastern United States. 



It was found also that timothy, the chief hay grass of this region, 

 was much longer lived and more productive in acid land when limed, 

 and that wheat, one of the principal cereals, yielded much more 

 heavily when treated in the same manner. "Within the last few 

 years the attempt in the acid East to cultivate alfalfa, the great hay 

 crop of the alkaline West, has conveyed the same lesson in a still 

 more striking manner, for alfalfa can not be grown satisfactorily in 

 any soil, however fertile, which has an acid reaction. When grown 



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