CALCAREOUS MANURES— PKACTICK 



85 



PRODUCT IN SHELLED CORN PER At RE 



UESCKIl'TION. 



1st course 2d course 

 1820. 1824. 



Oct. 13. ; October 16. 



Not marled 

 After inanurinfi;, 

 |Not marled until 1823, 



Marled in 1819— manared 

 with chaff, &c.in 1832. 



Bush. pk.'Bush. pecks. 

 2 j 16 1 



1 ' 28 



19 2 

 S^ 20 

 1 jnot measured 



3d course 4th course 



1828. 1832, 



October 13, October 19. 



Bush, pecks. Bush, pecks. 

 11 3J 9 S 



16 3 I 



19 2 not measured. j 



15 13 ' 



19 j 19 J , 



not measured. Inot measured.! 



The crops of wheat were throughout less injured bj^ the excess of marl 

 than the corn. 



For the crop of 1828, ploughed with three mules to each plough, from 

 six to seven inches deep — seldom turning up any subsoil, (which was fnr= 

 merly within three inches of the surface,) and the soil appearing still darker 

 and richer than when preparing for the crops of 1824. The ploughing 

 of the square not marled (A) no where exceeded six inches ; yet that depth 

 must have injured the land, as I can impute to no other cause the remarka- 

 ble diminution of product, through four courses of the mild four-shift rota- 

 tion. It was evident that a still greater depth of furrow was not hurtful to 

 the marled land. A strip across the field, in another place, was in 1828 

 ploughed eight inches deep for experiment, by the side of another of four 

 inches, and the corn on the deepest ploughing was the best. Another strip 

 was trench-ploughed twelve inches deep, without showing any perceptible 

 difference, either of product or in the effects of damage from the excess 

 of marl. 



This .square left without marl was the land previously referred to (page 

 27) as showing a diminished product through tliree successive courses of the 

 rotation recommended by the author of ' Arator' as enriching. Since, 

 another crop has been made and measured, and found to be still smaller 

 than any previous. To whatever cause this continued falling off, for 16 

 years, may be attributed, it is at least a remarkable contradiction to the 

 doctrine of vegetable matter serving alone to make poor land rich. 



Much trouble has been encountered in attending to this isxperiment, and 

 much loss of product submitted to, since its commencement, for the pur- 

 pose of knowing the progress and extent of the evil caused by the excess 

 of marl. But another portion of the field, marled as heavily in 1824, and 

 where equal damage was expected to ensue, has been entirely relieved by 

 intermitting the corn crop of 1828, sowing clover, which (by manuring 

 with gypseous earth, or green-sand earth, at 20 bushels to the acre,) pro- 

 duced well, and which was left to fall and rot on the land. The next growth 

 of corn on this part of the field (1832) was free from disease, and though 

 irregular, seemed to the eye to amount to full twenty-five bushels to the acre. 



After 1836, the rotatioji and management of this field ceased to be re- 

 gular or uniform, as previously; and also, by cross ploughing, &c., during 

 so many years, marl had necessarily become slightly diftused over the space 

 designed to remain without marl. Therefore no more measurements were 

 made, as they could no longer, be relied on for accurate comparison. The 

 unmarled part, even with its slight accidental gain of marl from the sur- 

 rounding ground, and half the piece having also been dressed with putres- 

 cent manure in 1832, (as stated above,) is but very little improved 

 since 1820. 



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