252 CALCAREOUS MANURES— APPENDIX. 



land. This at least proves that gypsum contained [if any] in the marl has 

 not caused the disease. Tliepoor land, lightly marled in 1819, sliowed but 

 little of the disease, and none was found in the piece not marled, nor in any 

 marled since the last crop [or now first cultivated since being marled.] 



" In Court-House field the injury was confined to 19 acres, the poorest 

 part of the field, which was in corn in 1821,* marled and fallowed, 1822, 

 and in wheat 1823, corn 1824. The remainder of the old land, which had 

 not been cropped so severely, and was covered as heavy with Llue marl, 

 brought a fine crop, quite free from the disease. The new ground was 

 mostly marled very heavy (800 bushels of 45 per cent.)! and this and all my 

 former clearings, (some marled equally heavy,) were also quite free. These 

 facts satisfy me that it was not the quality, but the over quantity of marl 

 which has caused the evil; and that the land which has escaped, owes its 

 safety to its containing" more vegetable matter. I forgot to state that on 

 some of the lightest spots of South Field the wheat was much injured, 

 though blue marl was used there. 



"If I had followed iny own advice to others, " to put no more marl at 

 first than would but little more than neutralize the soil, and repeat the dress- 

 ing afterwards," this evil would not have fallen on me. The present loss is 

 not much ; but it makes me expect the same on all similar land, marled as 

 heavily. I shall endeavor to avoid it, by giving vegetable matter to the soil ; 

 either by manuring, or by allowing one or two more years of grass in the 

 first term of the rotation. Why the quantity of marl applied should do harm 

 in any case, is more than I can tell ; but I draw this consolation from the dis- 

 covery—if a certain quantity, (say 500 bushels per acre,) is too much for 

 present use of the soil, it proves that it will combine with more vegetable 

 matter, and fix more fertility in the soil, than I had supposed. That the 

 second crop should be injured, and not the first, is owing to the unbroken 

 state of the shells at first, and, by their being reduced, twice as much calca- 

 reous matter is in action after a few years." 



Thus it will be seen, from these entries made at the time, that I took a 

 correct view of this great and unlooked-for evil, and was by no means dis- 

 couraged, or induced to lessen my efforts in marling. But in all after 

 operations on poor land, the quantity was lessened from 500 and 600 

 bushels, (and even more of the poorest marl,) to about 300 bushels. With 

 this alteration, the operation was continued with as much zeal as before ; 

 and also at a later time on another farm (Shellbanks) purchased afterwards, 

 and where I marled upwards of 400 acres. 



When this injury was first discovered, about 250 acres of very similar 

 land had been marled so heavily that the like mischief was to be looked for 

 in the next crop, and thenceforward, if not guarded against. For a more 

 full account of this disease, and my opinions thereon, I must refer to what 

 has been before published.^ It is sufficient here to say that by pursuing the 

 means there advised— in allowing more rest from grain crops, furnishing 

 vegetable matter to the land, in its natural cover of weeds, in clover and 

 farm-yard manure so far as the limited supply sufficed — that no very great 

 loss was subsequently suffered, except in the field where the disease was 

 first discovered, and which was marled in 1819, This field was too remote 

 and inconveniently situated, to be manured from the barn-yard ; and from 

 that and other causes, (including the failure of the first seeding of clover,) 

 that field only still shows injury from marling in the present crop (1839;) 



* Exp. 11, p. 86. 



t Exp. 1 to 4, pp. 72 to 77. 



j Essay on Calcareous Manures, ante. 



