110 [Senate 



always the best ; but the one which puts the soil into the best con- 

 dition, and helps to make the most permanently enriching manure, 

 must be properly appreciated. The one may draw the treasure out of 

 the soil, but the other accumulates it ; the one expends the wealth of 

 the land, the other collects it. If, for instance, a crop of green herb- 

 age be turned beneath the soil, though yielding of itself no return 

 whatever, yet if it increases the following crop of corn from thirty to 

 fifty bushels the acre, and a subsequent crop of w^heat from fifteen to 

 twenty-five bushels, it becomes, in reality, equal in nett value, to 

 twenty bushels of corn and ten of wheat. 



In devising a good rotation, the following objects must be taken 

 into consideration, viz : — 



1. To exhaust the soil as little as practicable ; 



2. To return as much manure as possible again to the soil ; 



3. To obtain, by a variation of different crops, an equal propor- 

 tion of the varions fertilizing ingredients from the soil ; 



4. To prepare for future crops ; 



5. To prevent the growth of weeds ; 



6. To adapt the application of manure best to the respective needs 

 of the different crops following that application ; 



7. To adapt the crops to the physical and chemical condition of 

 the soil, as in relation to dryness and moisture, lightness and tenacity, 

 poorness and fertility ; 



8. To adapt them to the market, to the climate, and to an equal 

 distribution of the labor of the farm, throughout the year. 



In attaining all these objects, a thorough knowledge is required of 

 the nature of the soil, and of the effect of the different crops upon it, 

 and upon succeeding crops, and of the influence of manures upon 

 them. This knowledge is yet in its infancy. Numerous, well- 

 directed, and accurate experiments, must be performed, and perhaps 

 occasional chemical analysis resorted to, before full information on all 

 these points is attained. A very brief examination of what is already 

 known, may be highly useful, as well as assist further investigation. 

 The limits of this essay, admit, however, of only a general classifica- 

 tion of properties. Plants may be grouped, with reference to these 

 points, into several divisions : — 



1. Cereal grasses — or grass-like, grain producing plants, as wheat, 

 oats, barley, rye, &c. As these are all narrow-leaved, and all ripen 

 their seed before they are cut, they are eminently exhausting to the 



