154 BOARD OF AGRICULTURE. 



ferred yesterday to the table of Dr. Weiske,of Proskau, which 

 gives the ingredients of the stubble and roots of various crops 

 remaining on and in an acre of land after harvest. (See 

 page 95.) This is the first, or nearly the first, exact experi- 

 ment of the kind that has ever been made, and these observa- 

 tions must be repeated here and there, on different soils, 

 before we can get entirely trustworthy data, to enable us to 

 make a satisfactory calculation. Still, these first results will 

 serve a very good purpose. 



In the case of rye, for instance, you have 3400 lbs. of dry 

 vegetable matter remaining in the soil to the acre. Ordinary 

 rye straw contains some fourteen per cent, of moisture. The 

 vegetable matter in the table is considered free from that 

 variable amount of water which is always present in the plant, 

 unless it has been dried at the temperature of 212'^. In the 

 case of barley, we have about half as much as in rye — 1515 

 lbs. ; in oats, 2200 lbs. ; in wheat, 2240 lbs. ; in red clover, 

 6580 lbs. ; in buclcwheat, 1630 lbs., and so on. You see that 

 in the amount of matter remaining in the soil, the clover crop 

 far surpasses any other. If it were a fact that the organic 

 vegetable matter of one crop remaining in the soil, supplies 

 the food for the following crop, you see that what remains in 

 the soil from a good clover crop would furnish the material 

 for about three oat or wheat crops. It is not the fact, that 

 the vegetable matter from one crop acts as such directly to 

 support the succeeding crop ; but it is a fact that some of tlie 

 ingredients of the vegetable matter are of use to the succeed- 

 ing crop, and in some places must be supplied, in order that 

 the succeeding crop may grow. That is especially true of 

 nitrogen. We have in tlie clover field a residue of 180 lbs. 

 of nitrogen ; in rye, wc have 62 lbs. ; in oats, 25 lbs. ; in 

 some other crops we have a larger quantity ; you see how the 

 figures run. (p. 95.) This nitrogen came partly from the 

 atmosphere by the foliage, and partly from the soil taken up by 

 the roots. The clover residues contain three times as much 

 nitrogen as those of rye and 7 to 8 times as much as tliose of 

 wheat, barley, or oats. We have 246 lbs. of lime remaining 

 in the residue of clover — three times as much as in that of 



