210 ROTATION OF CROPS. 



has proved another thing, that a different plant, or crop, succeeds well upon tliis very spot. 

 This last plant may also cease to produce itself vigorously, and then again another change is 

 called for. These successive changes is called a rotation ; and these rotations have been fol- 

 lowed for many years, during which the direct application of manures has been dispensed with. 

 The fact that success attends the retation of crops, proves that plants do not require the same 

 element of nutrition in the same proportion. Other views of the subject have been entertained, 

 but there is no doubt that the foregoing is the true one, viz. that a plant so far takes up and 

 removes the nutritive elements, that the amount necessary for perfection is not accessible to the 

 roots. Now it is highly important that every farmer should be fully impressed with the fact 

 that whatever rotation of crops is adopted, the exhausting process goes on. This is denied by- 

 many, especially by the wheat growers who rely upon plaster and clover to sustain their wheat 

 crops. Every bushel of wheat contains a large amount of potash, and of the phosphates ; and 

 as plaster does not contain either, it is undeniable that the exhausting process is going on by 

 this mode of cropping. So too, pasture lands, although their productiveness may not diminish 

 rapidly, yet when the milk of cows is consumed at a distance, in the form of butter and cheese, 

 these too, in the end, will show the same fact. There is another position equally tiue, viz. 

 that where a farmer has carried through his rotation, the soil at the end of the rotation is 

 thoroughly exhausted. It is not in one element only which is reduced in quantity below the 

 standard of fertility, but there are several, and the farmer who expects that plaster, in this 

 stage of cultivation will restore his fields to the natural fertility, will be assuredly mistaken. 

 And a field thus treated, never can be restored to its original Condition, unlets the removed 

 matters are added to it. It may recover by rest its apparent feitility, yet rest gives time 

 merely for change of condition, not the addition of a single atom of inorganic matter. 



I have explained the grounds upon which a rotation of crops has been recommended, viz. 

 the unequal exhaustion of soils of the valuable elements, by certain classes or groups of plants, 

 so that, although exhaustion must take place, still the farmer is enabled to pursue a plan of 

 cropping, for several successive years, without the labor of adding each year manures or com- 

 posts from his yards. Those farmers who pursue a plan of rotation, are governed by one prin- 

 ciple at least, viz. never, in all his changes of crops, to allow those to follow each other which 

 require the same elements of food to the same amount. Thus, oats should not follow a crop 

 of wheat or Indian corn, or as the common expression is, two white crops should not succeed 

 each other. To us, whose observations are confined to comparatively new lands, this principle 

 does not appear so important, inasmuch as it is customary to plant the same crop, on the same 

 land, for a number of years : but soils which have been cultivated for centuries, and which 

 have been much exhausted, and where the crop must be supplied with nutriment almost di- 

 rectly from the hand of the farmer, it is quite different. The rotation, let it be remembered, 

 succeeds because plants demand unequal quantities of the rare and expensive elements, the 

 alkalies and phosphates for example j not because these plants do not require them all, and can 

 live without them. The rotation which wheat growers of western New-York adopt, is mainly 

 one of clover, aided by plaster, and wheat and occasional year of fallow, which is really a year 



