3d8 IMPROVING POOit SOIlI. 



Observations 5th\f^ The planting of forest trees, as tendu^g to dgfend 

 re^Sine'^the the more valuable plants from the injury they are exposed 

 .improvement to in a poor soil, is an object well worth attention t more 

 •fpoprBoUs^ particularly oa grass land. Some author, in the Academy 

 of Sciences, has proved, that land exposed to a long current 

 of wind, which btew over a large tract of barren waste, 

 would piroduce nothing but poor grasses, so long as it re, 

 mained thus exposed ; but, when this current was broken 

 by a few hedges and plantations of forest trees, it became 

 capable of propagating and rearing the most useful and pro- 

 line plants. Perhaps the atmosphere attracted by the trees,^ 

 parts with its electrical matter, which has been found highly 

 conducive to the growth of plants. The agitation given to 

 the air, when driven against the hedges and trees, may dis* 

 pose it to a decomposition higlily favourable to its yielding 

 nourishment; and on this principle, I apprehend, that in 

 districts where the air js partially obstructed by hedges and 

 trees, it always tends more to the amelioration of land, 

 than where stone walls and mud fence are employed. 



6thly, Planting oziers, on wet land, is anotlicr mode of 

 answering the end proposed in the question. Lands not 

 worth ha)f-a-croM n an acre on the side of the Trent,' have 

 been planted with oj^iers, at the expence of four pounds 

 per acre, and since let for four guineas an acre per annum. 



7thly, One source of barrenness in soils is the presence 

 of the calx of iron. The calx or rust of iroji may be known 

 by the redness or blueness it gives to most soils, with which 

 it is incorporated. It may appear extraordinary to many, 

 that this iron should be the result of vegetation, but the 

 fact is incontrovertible*. I have reason also to believe, 

 from observation, that some trees and plants, are more 

 disposed than others to produce the mineral earth ; audit 

 behoves the improver of the soil to ascertain, what these 

 plants and trees are. Of trees, the willow tribe^ anrf 

 alder; amongst plants, the whole order of rushes^ and 

 a^ove all, Mosses, most assuredly abound in iron, and 

 ought never to be sulFerijd to exist on cultivated land. 



.* Vide Thompson's Cheniistry, Vol. IV. page 228; Chaptal, 

 Vol. III. page 170. 



8thly, 



