Continuous Growth of Wheat Without Manure. 35 



CONTINUOUS GROWTH OF WHEAT UPON THE 

 SAME LAND FOE FOETY YEAES WITHOUT 

 MANUEE. 



The third section of the report of the first twenty years' 

 experiments is concerned with the average annual result over 

 the last twelve years by each description of manure applied 

 year after year on the same plot. As, however, the report 

 of the second twenty years continues the same line of 

 inquiry over a much longer period, it will suffice to glance 

 at only one or two of the leading features given under this 

 head in the first report. It is observed that an average 

 annual produce of wheat, amounting to from 15 to 16 

 bushels of grain, and from 15 to 16 cwt. of straw, without 

 manure of any kind, is looked upon by many as an extra- 

 ordinary yield, and as indicating a somewhat unusual 

 quality of land. There is no doubt it bears a higher 

 proportion than might have been expected to the produce 

 obtained, even under rotation with periodical manuring, in 

 a large majority of cases where land is badly farmed ; 

 whilst deficient range and aeration of soil, luxuriant weed 

 growth, and defective manuring, all contribute to the 

 miserable result. The experimental land, though kept 

 extremely clean, was not, however, ploughed more deeply 

 than in the ordinary practice of the farm ; and there can 

 be little doubt that a large proportion of those soils of the 

 country which are recognised as possessing average wheat- 

 producing qualities would yield very similar results, if kept 

 equally clean and otherwise as well cultivated ; whilst some 

 would,, under like conditions, produce much more, though 

 many light soils probably much less. 



Eegarding the history of the permanently unmauured 

 plot over the two periods of twenty years each, it must be 

 remembered that the last time this land received any manure 

 was in 1839. The turnip crop of that year was succeeded 

 by barley, peas, wheat, and oats, all unmanured, so that by 



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