426 DAMAGE TO CROPS BY MARLING. 



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 my own advice to others, ' to put no more 

 marl at first than would but little more than neutralize the soil, and 

 repeat the dressing 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 endeavour to 

 avoid it, by giving vegetable matter to the soil ; either by manur- 

 ing, 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 discovery 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 mor,e 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 calcareous 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 discouraged, or induced to lessen my efforts in marling. 

 But in all later 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 con- 

 tinued with as much zeal as before; and also at a later time on an- 

 other 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 in 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 in- 



* Essay on Calcareous Manures, ante, 155. 



