132 Extracts from the Journals. [July, 



ON THE SUCCESSIVE DEVELOPMENT OF VEGETABLE 

 MATTER IN THE CULTIVATION OF WHEAT. 



M. Mathieu de Dombasle, who is so well known in France 

 from his scientific researches into the means of preventing bunt 

 in corn, has, in a memoir on the nutrition of vegetables, endea- 

 vored to overthrow an opinion generally entertained by cultivators 

 that plants do not exhaust land except during the period of fruc- 

 tification; that is from the time of fecundation to that of the 

 ripening of the seed. This opinion is founded on the generally 

 admitted fact that a crop mowed just after coming into flower ex- 

 hausts the land much less than if it is suffered to become ripe. 

 Thus Clover and Tares are considered not merely as innocuous, 

 but in some cases even as decidedly beneficial to the land. Be- 

 sides, we know that of all parts of vegetables the seeds are those 

 which, in the same bulk, contain the greatest quantity of nutritive 

 matter, and therefore, a priori, it is natural to conclude that they 

 require for their formation a greater quantity of nutritive princi- 

 ples. 



To these facts M. de Dombasle has opposed others quite as well 

 established, w^hich tend to prove that plants draw as much nour- 

 ishment from the soil at the beginning of their development as at 

 a more advanced period. For instance, amongst vegetables con- 

 sidered as the most exhausting there are some which in ordinary 

 cultivation are not allowed to produce seed, as Cabbages, Woad, 

 and Tobacco; and it is agreed that in nurseries where young 

 plants of Coleseed and Beet are raised for transplanting, the ground 

 soon loses its fertility.* 



M. Mathieu de Dombasle has not hesitated to attribute the 

 slight degree of exhaustion caused by certain green crops to the 

 circumstance of their leaving in the ground a quantity of roots, 

 which is very considerable compared with the whole mass of ve- 

 getation. To complete this organization, it may perhaps be use- 

 ful to remember that those green crops which exhaust but little, 

 or are beneficial to the soil, are gifted with the power of deriving 

 from the atmosphere the greater portion if not the whole of their 

 elements. In a former work M. Boussingault has made it appear 

 that all the vegetable matter produced in the course of a crop is 

 not found in it when mowed; in Clover, for example, the quantity 

 of organic matter remaining as an acquisition to the soil may 

 amount to more than 0.8 of the weight of the hay. We must 

 then set it down as a principle that every crop depauperates the 



* It is evident that these instances are not conclusive. The point is not to 

 prove that young crops <lo exhaust the ground, but to inquire vviiether they 

 exhaust it as much as when they are allowed lo ri'ien their seed. 



