24 The Landed Interest. 



appeared capable of obviating, they were 

 discontinued. With regard to red clover, when 

 the land becomes clover-sick, it was found that no 

 manure could be relied on to secure a crop, and 

 continuous crops of it are therefore impossible. 

 Experiments on the various root-crops were 

 continued for series of years, and the result 

 published ; also on sugar-beet ; and in 1 8/6 a 

 commencem.ent was made with potatoes. His 

 experiments on the corn-crops go on without 

 cessation. In 1856 an important series of ex- 

 periments was commenced on grass-land, which, 

 with very little change on each of the twenty 

 plots, has been continued to the present time. 

 The average of the past twenty years shows 

 that the natural produce may be doubled, and 

 even trebled, by the continuous use of special 

 Some of manures. Seeing that nearly two-thirds of the 

 special Cultivated area of this country, and all the un- 

 cultivated, are in grass, this series of experi- 

 ments is of very great interest and value. After 

 thirty-three successive wheat-crops it is not 

 surprising that the soil begins to exhibit symp- 

 toms of exhaustion. The rotation experiments 



