CHEMICAL MANURES. 91 



right in insisting you should begin with small experimental fields. M. 

 Lavaux, at the farm of Choisy-le-Temps, where the chemical fer- 

 tilizers are employed on nearly 675 acres, begun with a modest little 

 experimental field. 



After what I have just said, you will not be surprised if I speak 

 in detail and with a kind of partiality of the rules to which you 

 must bind yourself, in order to draw from an experimental field all 

 whk'li can possibly be drawn from it. 



A judicious agriculturist, and one animated by the desire to do 

 well, ought to make two kinds of tests here and there over the whole 

 extent of his domain, to know the true wants of the soil ; this consists 

 of peas and wheat sowed near each other on squares of 1 to. 2 yards. 

 If the two plants succeed equally well, the indication is certain 

 that the soil is provided both with minerals and azotic matter. If 

 the peas succeed and the wheat gives but a poor return, you may be 

 certain the land is provided with minerals and wanting in azotic 

 matter. Finally, if the return of wheat, without being excellent, is 

 better than that of the peas, it is a sure indication that the soil con- 

 tains azotic matter, but is wanting in minerals. These are certain 

 and easy means of acquiring positive indications of the differences 

 of composition shown by the different parts of a domain. But these 

 indications, although very useful, are not sufficient; they must be 

 pushed farther to find out what minerals are wanting, both in the 

 superficial and deeper beds of the soil. That is done without dif- 

 ficulty by means of the experimental fields. 



In an area of some importance it would be well to establish several 

 of them. One, which I will call the principal field, should compre- 

 hend all the plants included in the rotation to be adopted. , 



The choice of position is a point of great importance. You should 

 choose a part which as much as possible represents, by its exposure, its 

 nature and degree of fertility, the mean quality of the soil of the 

 whole area. The principal field ought to be composed of ten strips 

 of one square each, separated by a path of one yard in width. I 

 have said that the field ought to comprehend all, or at least the prin- 

 cipal, plants of the rotation, which would require.at least two or three 

 parallel series of culture; among the plants to be preferred, if one 

 cannot try them all, I would name the wheat, colza, or even the beet, 

 and a legume the pea or bean. By means of the wheat and pea you 

 will be informed of the state of the superficial bed, and by the beet 

 or colza of that of the deeper bed of the soil. Now there are two 

 elements to which you must pay particular attention if you would 

 have large returns with intelligence, certainty and economy. 



I have said that each plant ought to be submitted to ten different 

 methods of manuring on ten separate parcels. Here is the exact 

 indication of these manures : 



Wheat No. 1. Manure, 53,333 Ibs. the acre. 



No. 2. Manure, 26,666 



No. 3. Complete fertilizer, condensed. 



No. 4. Complete fertilizer. 



No. 5. Fertilizer without azotic matter. A L 



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