156 BOARD OF AGRICULTURE. [Pub. Doc. 



Some Practical Results from the Use of Manures in 



Rotation. 



The best land employed at Kingston in any of the rotation 

 experiments 3'ielded the year before the beginning of the 

 experiment (1892) an average of but 18 bushels of shelled 

 corn per acre. Similar soil in another portion of the same 

 field, under a system of continuous cropping without manure, 

 became so exhausted by the year 1896 as to produce in the 

 entire season Indian corn plants which were only about 5 

 inches high. 



It must be evident, therefore, that the attempt at soil reno- 

 vation was made upon land which was extremely exhausted. 

 A ptirt of the plan of the experiment was to ascertain the 

 relative efficiency of various rotations of crops in soil renova- 

 tion, and at the same time to gain as much light as possible 

 upon the best system of manuring where the whole or nearly 

 the whole dependence must be placed upon chemical manures. 



Some of the incidental advantages which it was hoped to 

 gain by practising systematic crop rotation were sunmiarized 

 in Bulletin No. 75 of the Rhode Island station, as follows : — 



(1) All plants do not draw to an equal extent upon the various 

 manurial ingredients of the soil. Furthermore, plants are unlike 

 so far as concerns their power to assimilate individual ingredients. 

 This is probably due to their sending their roots to different depths, 

 and also to an unlike solvent action of the root juices upon the 

 constituents of the soil.* 



(2) By rotating crops, injury by insects is lessened. 



(3) Losses caused by fungous and bacterial diseases may also 

 be materially reduced. 



(4) The soil is maintained in good tilth, which is an item of 

 great importance. Certain minute organisms which are helpful to 

 plants are more likely to increase in soil where crops are rotated 

 than where no regular system exists. 



(5) "Weeds are more readily eliminated or avoided where crops 

 are regularly rotated, than under an irregular, slip-shod system of 

 farming. 



* B. Dyer has shown that the acidity or sourness of the juices of the roots of 

 various phxiits varies to a marked extent. Journal of the Chemical Society 

 (England) , (55 (18S)4) , pp. 115-167. 



