EXPERIMENTS ON CLOVEIl. 137 



" That is well said," I remarked, " and very truly ; but I will not 

 interrupt the reading." 



" In the course of a long residence," continues Dr. Ycelcker, " in 

 a purely agricultural district, I have often been struck with the 

 remarkably healthy appearance and good yield of wheat, on land 

 from which a heavy crop of clover-hay was obtained in the 

 preceding year. I have likewise had frequent opportunities of 

 observing, that, as a rule, wheat grown on part of a field whereon 

 clover has been twice mown for hay, is better than the produce of 

 that on the part of the same field on which the clover has been 

 mown only once for hay, and afterwards fed off by sheep. These 

 observations, extending over a number of years, led me to inquire 

 into the reasons why clover is specially well fitted to prepare land 

 for wheat ; and in this paper, I shall endeavor, as the result of my 

 experiments on the subject, to give an intelligible explanation of 

 the fact, that clover is so excellent a preparatory crop for wheat, as 

 it is practically known to be. 



" By those taking a superficial view of the subject, it may be sug- 

 gested that any injury likely to be caused by the removal of a cer- 

 tain amount of fertilizing matter, is altogether insignificant, and 

 more than compensated for, by the benefit which results from the 

 abundant growth of clover-roots, and the physical improvement in 

 the soil, which takes place in their decomposition. Looking, how- 

 ever, more closely into the matter, it will be found that in a good 

 crop of clover-hay, a very considerable amount of both mineral 

 and organic substances is carried off the land, and that, if the total 

 amount of such constituents in a crop had to be regarded exclu- 

 sively as a measure for determining the relative degrees in which 

 different farm crops exhaust the soil, clover would have to be de- 

 scribed as about the most exhausting crop in the entire rotation. 



" Clover-hay, on an average, and in round numbers, contains in 

 100 parts : 



Water 17.0 



Nitrogenous substances, (flesh-forming matters)* 15.6 



Non-nitrogenous compounds 59.9 



Mineral matter, (ash) 7.5 



100.0 

 * Containing nitrogen 2.5 



" The mineral portion, or ash, in 1GO parts of clover-hay, consists 

 of: 



