GREEN MANURES. 273 



let they contain, undergo decomposition rapidly ; the best plan of 

 using them as manure would therefore hs to plough them in at once, 

 were there not certain objections to this. In the first place it cannot 

 always be done, on account of the season and the crops upon the 

 ground ; and then it might be imprudent to return to the earth the 

 noxious weeds which had just been pulled up, frequently full o. 

 seeds, which would not fail to make their existence known before 

 long. It is besides often impossible to bring loads of weeds to the 

 farmstead ; the best thing that can then be done is to change them 

 rapidly into manure in a corner of one of the fields which has pro- 

 duced them. This is readily accomplished by means of lime ; a 

 bed is first made of the weeds about 14 inches thick, this is then 

 covered with a thin layer of quick-lime, from half an inch to an inch 

 in thickness ; another layer of weeds is laid on, and then another 

 layer of quick-lime, and so on in succession. After a few hours the 

 action between the dry lime and the moist herbage begins, and it 

 may be so intense as even to go the length of burning, to prevent 

 which the pile must be covered with earth or with turf, and every 

 means used to prevent the access of air. The process is generally 

 complete within twenty-four hours, and the heap may then be spread 

 as manure. Before proceeding to such an operation, however, it 

 would be highly proper to calculate its cost. All depends on the 

 price of the lime and the labor ; and all things considered, I myself 

 much doubt whether the plan could be followed with advantage. 



Green manures. Under this title I include the green pa°rts of 

 vegetables which form part of our crops, such as the haum of po- 

 tatoes, the outer leaves of carrots, cabbages, beet, turnips, &c. 

 These articles are at once forage and manure, and it is for the hus- 

 bandman to decide in conformity with his position and particular 

 resources whether he ought to bury them at once, or to use them 

 first as food for cattle. 



From my own experience I should say that the leaves of beet 

 and of turnips, and potato haum were articles which ought only to 

 be given to cattle in cases of necessity. It is generally much better 

 to bury them in the ground immediately after the crop is gathered ; 

 if they be very indifferent food, they are on the contrary excellent 

 manure, superior in quality even to the best farm dung. From the 

 experiments I have made on this subject, I find that the potato tops 

 from an acre of ground may be equal to 6 or 7 hundred weight of 

 that manure presumed to be dry ; and the leaves of the beet, from 

 the same extent of surface, are equal to more than 21 hundred 

 weight of the same manure, also in a state of dryness. It is among 

 green manures that we are to class the sea-weed or marine plants, 

 which in many places are employed for improving the soil. These 

 cryptogamic plants, which abound in azote, have a fertilizing power 

 superior to that of common dung, a fact which explains the great 

 store which is set in Brittany by the sea-weed that is collected on 

 its coasts. Sea-weed is employed either fresh and as it comes from 

 the sea, or half dried or macerated, or roasted, and even partially 

 bijmed. It appears to act at once in virtue of the azotized or- 



