EXPERIMENTS ON CLOTEE. 135 



as a mulch, and the second growth of clover would be encouraged 

 by it. Mow this second crop again, about the first week in August. 

 Then, unless it was desirable to continue the process another year, 

 the land might be plowed up in two or three weeks, turning under 

 the two previous crops of clover that are on the surface, together 

 with the green-clover still growing. I believe this would be better 

 than to let the clover exhaust itself by running to seed. 



CHAPTER XXV. 

 DR. VCELCKER'S EXPERIMENTS ON CLOVER. 



In the Journal of the Royal Agricultural Society of England, for 

 1M68, Dr. Voelcker, the able chemist of the Society, and formerly 

 Professor of Agricultural Chemistry, at the Royal Agricultural 

 College at Cirencester, England, has given us a paper " On the 

 Causes of the Benefits of Clover, as a preparatory Crop for 

 "Wheat." The paper has been repeatedly and extensively quoted 

 in this country, but has not been as critically studied as the impor- 

 tance of the subject demands. 



"Never mind all that," said the Deacon, "tell us what Dr. 

 Voelcker says." 



"Here is the paper," said I, " and Charley will read it to us." 

 Charley read as follows : 



" Agricultural chemists inform us, that iu order to maintain the 

 productive powers of the land unimpaired, we must restore to it the 

 phosphoric acid, potash, nitrogen, and other substances, which 

 enter into the composition of our farm crops ; the constant removal 

 of organic and inorganic soil constituents, by the crops usually sold 

 oflF the farm, leading, as is well known, to more or less rapid dete- 

 rioration and gradual exhaustion of the land. Even the best 

 wheat soils of this and other countries, liecome more and more im- 

 poverished, and sustain a loss of wheat-yielding power, when corn- 

 crops are grown in too rapid succession without manure. Hence, 

 the universal practice of manuring, and that also of consuming oil- 

 cake, corn, and similar purchase! food on land naturally poor, or 

 partially exhausted by previous cropping. 



" Whilst, however, it holds good as a general rule, that no soil 

 can be cropped for any length of time, without gradually becoming 



