No. 4.] FEUIT GROWING. 149 



Graphics," for 1890, published by authority of the Secre- 

 tary of Agriculture. For the whole country the average is 

 1.19 tons. This includes all the hay, whether cared for or 

 neglected. My own impression is that half a ton would be 

 nearer the actual, natural product of average lands ; yet, 

 that wc may not be led astray by an under-estimate, I will 

 call it two-thirds of a ton. Now, what are the more valuable 

 constituents removed from the soil by this amount of prod- 

 uct, — those which are soonest exhausted and which tax 

 the soil to its limit? According to Prof. C. A. Goessmann, 

 there would be required, in round numbers, 4 pounds of 

 phosphoric acid, 12 pounds of nitrogen and 16 pounds of 

 oxide of potassium. How far would these substances go 

 towards supplying the requirements of a crop of apples ? 



An analysis furnished by Prof. J. W. Clark of the Missouri 

 Agricultural College Experiment Station, in Bulletin No. 10, 

 gives the ash constituents of the Ben Davis apple, from 

 which it appears that a crop of 300 bushels would remove 

 from the soil, in round numbers, 4 pounds of magnesia, 7 

 pounds of lime, 7 pounds of phosphoric acid and 43 pounds 

 of potash. This, it must be remembered, is for the fruit 

 alone of a very moderate yield. If we add to this the amount 

 of these same substances permanently stored up in the growth 

 of the roots and branches, and also that contained in the 

 foliage, winch may or may not be retained as it falls upon 

 the surface of the soil or is blown away by the winds, I think 

 I shall be justified in estimating that the least quantity of 

 phosphoric acid and potash essential for the production of a 

 full yield of apples would be 14 pounds of the former and 80 

 pounds of the latter. If, as shown by a grass crop, the 

 natural forces will furnish but 4 pounds and 16 pounds of 

 these substances respectively, then it follows that art must 

 supplement nature by 10 pounds of phosphoric acid and 64 

 pounds of potash, or be satisfied with less than a full produc- 

 tion. 



It is a source of regret that we have as yet so few analyses 

 bearing upon matters of this kind that no absolutely certain 

 conclusions can be drawn from them ; but it is hoped that, 

 through the large number of experiment stations now in 

 active operation, these and many other vital questions will 



