72 PROOFS OF ACID SOILS. 



always beneficial results ; and that this is the best as well as cheap- 

 est mode of their application.] 



On one of .the washed and barren declivities (or galls) which are 

 so numerous on all our farms, I had the small gullies packed full 

 of green pine bushes, and then covered with the earth drawn from 

 the equally barren intervening ridges, so as nearly to smooth the 

 whole surface. The whole piece had borne nothing previously ex- 

 cept a few scattered tufts of poverty grass (aristida gracUis) and 

 dwarfish sorrel, all of which did not prevent the spot seeming quite 

 bare at mid-summer, if viewed at some distance. This operation 

 was performed in February or March. The land was not culti- 

 vated, nor again observed, until the second summer afterwards. At 

 that time, the piece remained as bare as formerly, except along the 

 filled gullies, which, throughout the whole of their crooked courses, 

 were covered by a thick and uncommonly tall growth of sorrel, re- 

 markably luxuriant for any situation, and which, being bounded 

 exactly by the width of the narrow gullies, had the appearance of 

 some vegetable sown thickly in drills, and kept clean by tillage. 

 So great an effect of this kind has not been produced within my 

 knowledge though facts of like nature, and leading to the same 

 conclusion, are of frequent occurrence. If small pines standing 

 thinly over a broom-grass old-field are cut down and left to lie, un- 

 der every top will be found a patch of sorrel, before the leaves have 

 all rotted. 



3d. The growth of sorrel is not only peculiarly favoured by the 

 application of vegetables containing acids already formed, but also 

 by such matters as will form acid in the course of their decomposi- 

 tion. Farm-yard manure, and all other putrescent animal and 

 vegetable substances, form acetic acid as their decomposition pro- 

 ceeds.* If heaps of rotting manure are left without being spread, 

 in a field but very slightly subject to produce sorrel, a few weeks 

 of growing weather will bring out that plant close around every 

 heap ; and for some time the sorrel will continue to show more 

 benefit from that rank manuring than any other grass. For several 

 years my winter-made manure was spread and ploughed in on land 

 not cultivated until the next autumn, or the spring after. This 

 practice was founded on the mistaken opinion, that it would prevent 

 much of the usual exposure to evaporation and waste of the manure. 

 One of the reasons which alone would have compelled me to aban- 

 don this absurd practice was, that a crop of sorrel always followed, 

 (even on neutral or good soils that before barely permitted a scanty 

 growth of it to live), which so injured the next grain crop as 

 greatly to lessen the benefit from the manure. Sorrel unnaturally 

 produced by such applications does not infest the land longer than 



* Agr. Chein. p. 187. (Pliil. ed.) 



