SOIL EXHAUSTION AND ROTATION OF CROPS. iff 



tion regarding a subject of great practical importance, I am happy 

 in being able, through the courtesy of Secretary Gold, to present 

 here two lectures delivered before the Connecticut Board of Agri- 

 culture at their last session. 



Soil Exhaustion and Rotation of Crops. 



BY TltOF. S. W. JOHNSON. 



Mr. Chairman and Gentlemen: Sometime since, I received 

 from Mr. Gold, a letter asking me to address the Board of Agri- 

 culture and the gentlemen assembled on this occasion, on 

 Exhaustion of Soils and Rotation of Crops. In that letter Mr. 

 Gold says : 



" We want to go further than the common theory of rotation 

 leads us, and to inquire why some crops may be grown for several 

 years in succession, as onions and buckwheat, why corn does not 

 succeed after turnips, why does land become clover-sick. 



" Why does the culture of certain crops tend to make the farm 

 richer, while other crops only make it poorer, and in both cases, 

 the gross amount of minerals and ammonia contained in the crops 

 may be the same, or even greater in the enriching crops ? 



"Are there certain periods of plant growth which may be 

 called the enriching period, and others, as the fruit season, the 

 exhausting ? 



" Is not wheat, the prince of cereals, the greatest exhauster of 

 the soil for the product taken from a given area ? 



" Tobacco should not be a very exhausting crop ; yet from the 

 fact, that for the particular purpose for which we cultivate it, a 

 very luxuriant growth is required, do we not need to furnish more 

 plant food than can be assimilated, much of which is lost in the 

 air, and washes away ? 



"The physical condition of the soil as it is left by different 

 crops is worthy of notice. 



' Wheat grows well after peas and clover, also after tobacco ; 

 but is not this last owing to the manure left over by the tobacco 

 and the good preparatory culture ? 



" Corn does not do well after buckwheat, but potatoes do well. 



" Perhaps my facts may not be facts, but they are believed by a 

 great many farmers, and we want the whole subject overhauled 

 and explained." 



After getting here on the ground, and looking over the material 

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