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THE EFFECTIVE USE OF LAND AS SHOWN BY YIELD 7 
Notwithstanding an enormous increase in acreage of these crops 
during the period covered by the data, the yields indicate a general 
upward trend. The increase in the annual harvested acreage for 
these crops is shown in Table 2. 
TABLE 2.—Increase in the average harvested acreage of corn, wheat, oats, and 
potatoes, 1885-1889 compared with 1920-1924 
Average Average Per- 
Crops annual annual centage 
acreage acreage in- 
1885-1889 1920-1924 crease 
WOT Bee eee ae eee es oer oe aa ee ee ee re a See 73, 796,000 | 102, 737, 000 39 
Wiktent Saar: RPE S) EM Poe Oe EPS LE A Nes Se ed 35,911,000 | 59, 836, 000 67 
Onis en el Ne. Ray WER BEERS Ss) a 25, 536,000} 42, 503, 000 66 
IROLATOCS ens ase oie aoa aaa eee es eee saa eee meso ee eae eee 2, 409, 000 3, 814, 000 58 
A considerable part of this expanded acreage, especially in the 
case of wheat, was on soils that produced yields below the national 
average for that crop. 
The average yields at the end of the period compared with the 
beginning show a rise of 4.3 bushels for corn, 2 bushels for wheat, 
3.9 bushels for oats, and about 30 bushels for potatoes (Table 1). 
Several times during the period a tendency to declining yields was 
indicated, but this was apparently temporary. The percentage of 
increase is 18 for corn, 17 for wheat, 14 for oats, and 39 for potatoes. 
The final averages shown in Table 1, that is, the averages for the 
various crops during the five-year period centered on 1923, do not 
mark the highest average yields attained to date. Higher average 
yields per acre are indicated as follows: For corn, 29.5 bushels during 
the five-year period centered on 1921; for wheat, 15.4 bushels dur- 
ing the five-year period centered on 1913 and 1914; for oats, 33.8 
bushels during the half decade 1914-1918; and for potatoes, an 
average of 108.7 bushels per acre during the five-year period centered 
on 1922. The lower yield of wheat and oats in the last few years 
is doubtless to be explained in part by the lower prices obtained 
since 1921, which, at the higher wages paid farm labor, did not per- 
mit so thorough cultivation as during the war years. 
It has been suggested by some individuals that in addition to the 
depressing influence resulting from the expansion of our crop area 
onto drier and poorer lands, the upward trend of our crop yields has 
tended to be depressed by declining fertility of our old crop land. 
This theory can not be substantiated by the trend in yield of these 
crops in most of the older, humid portions of the United States. 
Whitney, Schreiner, and others have stated that in general it has been 
almost a natural process for a soil to increase in fertility under 
intelligent human occupation. There are indeed many local 
instances where soil deterioration, through ignorance, inertia, and 
economic pressure has occurred in the past, and is still to be found. 
To quote Doctor Schreiner: 
It is true that the soil can be robbed of its store of available and soluble 
mineral plant food constituents by the carrying away of the crops from the 
land, but this so-called robbery is small, statistically almost insignificant, in 
