214 AGRICULTURAL REPORT. [1384, 385, 386 



the subject of draining of swamp lands, as well as plowing, I shall here dwell 

 upon it for a few moments. 



I have before observed (1J376), that the blue and green tints of clays, etc, are 

 generally caused by some combination of the protoxide of iron, and also tbat, 

 when such clays are exposed to the action of the air for some time, the green 

 or blue tint changes to gray, ye low or orange, in consequence of the conversion 

 of the protoxide into common rust. We have a familiar example of this change, 

 in the well-known process of copperas-dying; the fresh, green copperas contains 

 the protoxide in combination with sulphuric acid ; when it turns yellow, the 

 protoxide passes mto peroxide', it loses the copperas taste, and becomes insoluble 

 in water. This process, if kept in mind, will explain many phenomena import- 

 ant to the agriculturist. 



384. Few persons residing in regions where the soil or subsoil is yellow, can 

 bave failed to notice, that the yellow mud, when kept wet for a length of time 

 (especially in the warm season) — as for instance, in a deep mudhole — will 

 assume a blue tint in its lower portions; the wagoner wisely avoids the spots 

 where the wheels of some predecessor have brought up mud of this hue, because 

 it is a sure sign of a '' bad place." We have here the opposite of the process 

 which takes place in copperas dying; the iron yellow has been transformed into 

 blue, by the influence of fermenting vegetable matter, in points where the air had 

 little or no access. It will also be observed, that plants will not grow well where 

 the soil retains this hue — they wither or become rusty. Water flowing from 

 such spots, will deposit iron rust, like copperas water itself. Now, every one 

 knows how deleterious copperas water is to plants; and the same is true of the 

 water which collects on such spots ; the protoxide of iron which it contains, 

 however, is dissolved in carbonic, and vegetable acids, instead of sulphuric acid ; 

 the former being the product of the decay or fermentation of vegetable matter, 

 and present in all soils. 



385. Wherever water remain^ stagnant on or in soils for any length of time, 

 ith : s process takes place, and where this happens, plants — at least those we culti- 

 vate — will not thrive. And although the coirosive action of the solution of iron 

 thus formed is but rarely the only cause which, in such spots, acts ii juriously 

 to plants, its formation is an unfailing symptom of a want of proper drainage. 

 It frequently h ippens in level branch button. s, that the whole of the soil has 

 a bluish tint ; such soils invariably rust cotton, and are often considered natur- 

 ally unproductive. The remedy, however, is simple enough : correct the drain- 

 age of the land, and then turn up the soil as deep as may be practicable, ace >rd- 

 ing to circumstances ; but instead of planting it at once, falloiv it (or a season or 

 two. The bluish tint will be found to disappear rapidly under the influence of 

 the air (which transforms the protoxide into peroxide) and when it is gone, the 

 land will often times be found to be more productive even than adjoining tracts 

 in which, originally, no such tint was perceptible. Those who clear and cul- 

 tivate bottom land, will scarcely fail to recolhct having met with instances of 

 this kind in their experience. The beds of sloughs, which in after years gener- 

 ally become the most fertile portions of t e fields, will not produce as fieely at 

 first; but they will become productive more rapidly in proportion as the soil is 

 loosened and aera'ed more fre |uently ; they require fallowingat the very outset. 



386. It is commonly observed, that even in lands where the subsoil is very 

 deeply tinged with in>n, the surface soil is almost alwa\ s of a lighter tint ; hence 

 the conspicuous ''red washes" so frequently formed in fields, where the surface 

 soil has been washed away. This difference in color is owing, in some degree, 

 to the presence, in the surface soil, of dark colored vegetable matter, which cov- 

 ers the iron lint ; but very generally we also find a sma.ler absolute amount of 

 iron in the surface soil than in the sub^l ; as will h< seen by the table of analy- 

 ses, in the Claiborne County Soil, Pine Hill Soil, and Sod from Summit, as com- 

 pared with their subsoils. It seems, there ore, that this piocess, which we 

 obseiveto ba going on in all badly drained soils, with a considerable degree of 



