GEO WING AND MAINTAINING OBCHAEDS 



PROF. I. P. ROBERTS, CORNELL UNIVERSITV. 



IF a hole be dug in the hard field, 'hr 

 soil will show indications that it has 

 lost much of its original humus. Few 

 or no natural drainag^e channels will be 

 found. The soil, instead of being light and 

 loose, is sealed, and appears " harsh and 

 dead." If seeds be planted it is soon dis- 

 covered that the soil too often has not the 

 power to force the embryo plant to the sur- 

 face nor to push it to a vigorous growth 

 and mature fruitage. The vegetative 

 growth is too frequently dwarfed, which re- 

 sults in lack of power to bring all of the 

 fruit to perfection. Half of the fruit on the 

 tree not infrequently shows unmistakable 

 signs of semi-starvation. 



That this is the case is not strange if it is 

 considered what has been taken from the 

 soil in fifty years of cropping. Let it be 

 supposed that during the 50 years there 

 have been taken off of each acre ten crops 

 each of oats, wheat and corn and 20 of hay. 

 The following table shows the amount of 

 grain and roughage removed in 50 years, 

 and the value of the plant food approxi- 

 mately : 



AIR-DRIED MATERIAL REMOVED IN 50 YEARS. 

 Per acre. Lbs. Crops. LI s. 



Oats, 31 J4 bush 32 10 10,000 



Straw, 1,500 lbs — 10 15,000 



Wheat, 16 2-3 bush .... 60 10 10,000 



Straw, 2,000 lbs — 10 20,000 



Corn, 40 bush 60 10 24,000 



Stalks, 10 p.c. moisture, 



4,000 lbs — 10 40,000 



Hay, lYi tons, 3,000 lbs. — 20 60,000 



Total 179,000 



or 895^ tons. 



PLANT FOOD CARRIED OFF BY 50 ROTATIONS. 



Lbs. Niirogeii I't.osph iric I'otasli 



in round thousands. lbs. acid lbs. lbs. 



Oats, TO 165 69 48 



Straw, 15 69 42 265 



Wheat, 10 138 78 49 



Straw, 20 240 • 44 126 



Corn, 24 386 137 89 



Clover, 40 416 246 792 



Mix'ed hay, 60 ... . 882 246 792 



Total 2,296 732 1,929 



PLANT FOOD CARRIED OFF BY 50 ROTATIONS. 



No. of lbs. Cost p. lb. Value. 



2,296 nitrogen I2^c $287 00 



y^,^ phos acid 4^c 32 94 



1,929 potash 4>4c 86 80 



Grand total of the value of the plant food 

 carried off 50 years' rotation from each acre, 

 as above, $406.74. 



In 1895, among other investigations, an 

 attempt was made to determine the amount 

 of plant food » used by a single apple tree: 

 I. Plant food contained in the tree when 

 dug up, including branches, trunk and 

 roots ; 2. plant food removed by 20 avera^^e 

 crops of fruit ; 3, plant food removed by the 

 leaves. It was assumed that an acre would 

 grow 35 mature trees and that all of the 

 leaves were blown off the land, which, of 

 course, is not a fair assumption. 



The 20 estimated crops of apples remov- 

 ed $147 worth of plant food. The trees 

 contained $70 worth of plant food, and 20 

 crops of leaves $160 worth of plant food. 

 If it is assumed that all the leaves remained 

 on the ground, the total value of the plant 

 food contained in the wood and removed by 

 the apples was $217 per acre. If one-half 

 of the value of the plant food is in the leaves 

 for the 20 years to be taken, the value pet 



