14 



BULLETIN 511, U. S. DEPARTMENT OF AGRICULTURE. 



yields is $55. Aside from crop yields there are many economic and 

 sociological features which enter into the determination of the 

 market price of land ; for example, land in the Mississippi Delta will 

 produce as much or more corn per acre than the land in the northern 

 Mississippi Valley corn belt, yet the environment and conditions in 

 the Delta are such that the land sells for less than half what the corn- 

 belt land will bring. It is probable that in the cotton belt the eco- 

 nomic and social features of an area have more to do with regulating 

 the price of land than do crop yields. 



THE RELATION OF CROP ROTATIONS TO CROP YIELDS. 



Generally crop rotations affect crop yields. The rotations having 

 the largest percentage of those crops which add organic matter to 

 the soil, such as hay or pasture, are usually conducive to the best yields. 

 Regarding this factor, the data from all the records taken have been 

 compiled in Table IX to show the relation between the crop yield 

 and the normal average percentage of cultivated land in cotton. 

 When the combined data from aU the areas are compared (Table IX) 

 there appears to be no effect on crop yields of growing a larger or a 

 smaller percentage of the land to cotton. In the South Atlantic divi- 

 sion, however, where large quantities of commercial fertilizers are 

 applied each year, better crop yields are secured where 40 per cent 

 or more of the land is in cotton. This is probably due to the large 

 quantities of fertilizers used, a part of which remains in the soil from 

 year to year. 



Table IX. — Relation of percentage of cultivated land in cotton and normal acre yields 



of cotton. 



Areas. 



Delta areas 



South Atlantic division . . 



Intermediate areas 



Southwestern division 



Total.... 

 Average. 



Percentage of cultivated land in cotton. 



29 or less. 30 to 39. 40 to 49. 50 to 59. 60 to 69. 70 to 79. 80 to 89. ^^^^ 



83 



1,6s. 



1,133 

 801 

 737 

 800 



3,471 



Lbs 



1,316 



864 



696 



618 



3,494 

 874 



Lbs. 



1,280 

 901 

 611 

 609 



3,401 

 850 



1,6s 

 101,060 



844 

 645 

 533 



1163,082 



.... 771 



1,6s. 

 964 



730 

 600 



3,172 

 793 



Lbs, 



1,160 



780 



691 



590 



3,221 

 805 



Lbs. 



1,225 







975 



631 



2,821 

 940 



Lbs. 

 

 

 



500 



500 

 500 



It is generally found that the inherent fertility of the soil and the 

 climatic conditions largely determine the crop yields. Another im- 

 portant factor in determiruiig the crop yield in many parts of the 

 cotton belt is the quantity of fertilizers used. Of the areas studied, 

 in the nine having the highest yields of cotton 70 per cent of the farms 

 surveyed use commercial fertilizer, and the average application per 



