Yield of Wheat per Acre per Annum. 75 



been collected throughout the United Kingdom referring to 

 the number of acres under each crop, and to some other points ; 

 but, in regard to the important question of the amount of 

 produce obtained, either per acre or in the aggregate, there 

 were no returns nor any reliable information. In these 

 circumstances certain of the plots of the experimental wheat- 

 field at Eothamsted were, after careful observation and 

 comparison, selected as affording a trustworthy estimate of 

 the general yield over the country, and every year since 1862 

 there has appeared in the Times a letter containing an 

 estimate of the yield of wheat for the current season. The 

 results of the experimental wheat-field were regarded by Mr. 

 Caird, in the above-mentioned paper, as having "proved a 

 very satisfactory index of the general yield over the chief 

 wheat-producing area of the kingdom," and as affording 

 " the most instructive series of facts for the guidance of the 

 British corn-grower on record." The selected plots com- 

 prise: 



Plot 3. Unmanured every year, experiment commencing 

 1843-4. 



Plot 2. 14 tons farmyard manure every year, commencing 

 1843-4. 



Plot 7. Mixed mineral manure, and 4001b. ammonia-salts, 

 each year, 1851-2 and since. 



Plot 8. Mixed mineral manure, and 6001b. ammonia-salts, 

 each year, 1851-2 and since. 



plot 9. Mixed mineral manure, and 5501b. nitrate of soda, 

 each year, 1854-5 and since. 



In forming the estimate of the average produce per acre of 

 the country at large, the plan adopted is to take the mean 

 produce of the unmanured plot, of the farmyard manure 

 plot, and of the three artifically manured plots reckoned as 

 one, and to reduce the result so obtained to bushels of the 

 standard weight of 611b. per bushel. Merely as an example, 

 Table XVI., published in October, 1787, is given. Though ex- 

 perience proves that this mode of estimates leave but little to 



