EFFECTS ON ACID SANDY SOILS. 135 



since 1820. This and other spots, at first omitted for comparison, 

 when no longer fit for that purpose, were subsequently marled. 

 1849.] 



Experiment 11. 



The ground on which this experiment was made was in the 

 midst of nineteen or twenty acres of soil apparently similar in all 

 respects level, gray sandy loam, cleared about thirty years before, 

 and reduced as low by cultivation as such soil could well be. The 

 land that was marled and measured was about two hundred yards 

 distant from experiment 2, and both places are supposed to have 

 been originally similar in all respects. This land had not been culti- 

 vated since 1815, when it was in corn but had been once ploughed 

 since, November 1817, which had prevented broom-grass from, 

 taking possession. The ploughing then was four inches deep, and 

 in five and a half feet beds, as recommended in 'Arator.' The 

 growth in the year 1820 presented little except poverty grass 

 (Aristida gracilis), running blackberry briers, and sorrel and the 

 land seemed very little if at all improved by its five successive 

 years of rest. A small part of this land was covered with calca- 

 reous sand (20 per cent.), quantity not observed particularly, but 

 probably about 600 bushels. 



Results. 1821. Ploughed level, and planted in corn distance 

 5 by 3 J feet. The measurement of spaces nearly adjoining, 

 made in October, was as follows : 

 23 by 25 corn-hills, not marled (in A) made 2J bushels, 



or per acre, Ver 



, . . . , , 



23 by 25 corn-hills, marled (on the side B) 5| . 22 J n< 



1822. At rest. Marled the whole, except a marked square of 

 fifty yards, containing the space measured the preceding year. 

 Marl 45 per cent, and finely divided 350 bushels to the acre 

 from the same bed as that used for experiment 4. In August, 

 ploughed the land, and sowed wheat early in October. 



1823. Much injury sustained by the wheat from Hessian fly, 

 and the growth was not only mean, but very irregular ; but it was 

 supposed that the first marled place (on the side B) was from 50 

 to 100 per cent, better than the last marled, and the last superior 

 to the included square not marled (A), in as great a proportion. 



* 1824. Again in corn. The effects of disease from marling were 



