DISEASE OF CROPS FROM OVER-MARLING. 



133 



which closed a third side (B) of the marked square. The fourth 

 side was my neighbour's field. 



1824. In corn. The newly marled (on B) showed as early and 

 as great benefit as was found in 1820 on C and D; but yet was 

 very inferior to the old, until the latter was 10 or 12 inches high, 

 when it began to give the first known evidence of the very injuri- 

 ous effects of using this manure too heavily. The disease thus 

 produced became worse and worse, until many of the plants had 

 been killed, and still more were so stunted as to leave no hope of 

 their being otherwise than barren. The effects will be known from 

 the measurements which were made as nearly as could be on the 

 same ground as the corresponding marks in 1820, and will be ex- 

 hibited in the table, together with the products of the succeeding 

 rotations. Besides the general injury suffered here ih 1824, there 

 were one hundred and three corn-hills in one of the measured 

 quarter acres (in C), or more than one-sixth, entirely barren, and 

 eighty-nine corn-hills in another quarter acre (D). In counting 

 these, none of the missing hills were included, as these plants 

 might have perished from other causes. [This unlocked for disaster 

 diminished the previous increase gained by marling, by nearly one- 

 half; and the damage has since been still greater, at each succes- 

 sive return of cultivation until some years after 1832. 



Just before planting the crops of 1832, straw and chaff very 

 imperfectly rotted by exposure, and which contained no admixture 

 of animal manure, were applied at the rate of 800 bushels the 

 acre to half the square without marl (A, 1), and to the adjacent 

 parts of the marled land. The vegetable manure showed but slight 

 benefit, until after all the worst effects of excessive marling had 

 been produced; and the later operation of the manure served 

 barely to prevent a still farther diminution being exhibited by the 

 land injured by marl. 



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