324 AMERICAN AGRICULTURE. 



larger than those which closed their former bearing career, 

 proving that nature has been silently at work in renovating 

 the land for further use. The whole course of her opera- 

 tions is not yet known, but this much is satisfactorily ascer- 

 tained ; that she is incessantly engaged in producing those 

 changes in the soil, which enable it to contribute to vegetable 

 sustenance. Enough of lime, or potash, or silica may have 

 been disengaged to yield all that may be required for one 

 crop, which by that crop is principally taken up, and if 

 another of the same kind follows in quick succession, 

 there will be a deficiency; yet if a different crop succeed, 

 there may be found enough of all the materials it needs, fully 

 to mature it. A third now takes its place demanding mate- 

 rials for nutrition in forms and proportions unlike either which 

 has preceded it, and by the time a recurrence to the first is 

 necessary, the soil may be in a condition again to yield a re- 

 munerating return. These remarks apply equally to such 

 soils as have, and such as have not received manures ; un- 

 less, as is seldom the case, an accurate science should add 

 them in quantity and character, fully to supply the exhaustion. 

 The addition or withholding of manures, only accelerates or 

 retards this effect. 



Another prominent advantage of rotation, is in its enabling 

 such crops to have the benefit of manure, ay cannot jreceive 

 it without hazard or injury if applied directly upon them. 

 Thus wheat and the other white grains, are liable to over- 

 " growth of straw, rust, and mildew, if manured with recent 

 dung ; yet this is applied without risk to corn, roots and most 

 of the hoed crops ; and when tempered by one season's ex- 

 haustion, and the various changes and combinations which 

 are effected in the soil, it safely ministers in prolusion to all 

 the wants. of the smaller cereal- grains. A third benefit of 

 lion is, by brimiin^ the hind into hoed crops at proper in- 

 terxals, it clears it of any troublesome weeds which may 

 infest it. And still a further advantage may be found, in cut- 

 ting oil' the appropriate food of insects and worms, which in 

 the course of lime, by having a lull supply of their necessary 

 aliment, and especially if undisturbed in their quid liuunis, 

 will ofttimes become so numerous as seriously to interfere 

 with the labors of the, farmer. A change of crops and ex- 

 posure of the insects to frosts, and by the cluing! 1 of cultiva- 

 tion which a rotation insures, will make serious inroads upon 

 their numbers if it does not effectually destroy them. The 

 fanciful theory of the noxious excretions of plants first broached 



