CROP ROTATION IN RELATION TO SOIL PRODUCTIVITY 
43 
On each of the three selected plots, 24, 27, and 30. are applied 
annually the same quantities of the major nutrient elements. On the 
rotation plots ]ike applications are made for corn and oats, so that 
for each 3-year period the same quantities of fertilizing ingredients 
are applied per acre in rotation as in continuous culture. 
In Table 43 are given the average annual vields of seed cotton per 
acre and gains from fertilizers on the three selected plots in con- 
tinuous culture and in rotation for the period reported. The results 
recorded in Table 43 are from unlimed plots. 
Table 43. — Annual yields of seed cotton and gains per acre on experimental plots 
at Florence, S. C. 
Continuous culture 
Rotation 
Years 
avSSSfw Plover- Gain from *^g pbts aver- Gain from 
' age 21 and fertilizer a e 2 ™ 30 *& e 21 and fertilizer 
31 
27,30 
31 
Pounds 
Pounds 
Pounds 
Pounds 
Pounds \ 
Pounds 
1914 
2, 120 
1, 958 , 
162 
1,960 
1,665 
295 
1915 
1,995 
1,523 
472 
2,195 
1, 575 ' 
620 
1916 
1,060 
878 
182 
1,023 
1,407 
-384 
1917 
1,800 
1,080 
720 
1,605 
1,388 
217 
1918 
2,320 
1, 230 
1,090 
2,375 
1,838 
537 
1919 
1,605 
1,260 
345 
2,125 
1,853 
272 
6-year average 
1,816 
1,321 
495 
1,880 
1,621 
259 
It is to be noted that the average gain from fertilizers is greater 
without rotation than with rotation; nevertheless, the average yield 
on the fertilized plots in rotation is greater than that on the cor- 
responding plots in continuous culture. 
In Tables 44 and 45 are given the evaluations of rotation and the 
additive effects of rotation and the use of fertilizer. 
Table 44. — The effects of rotation and of the use of fertilizer on the yields of seed 
cotton 
[Rotation and fertilization practiced separately] 
Relative 
value of 
Increase rotation, 
Average 
over check as corn- 
Cultural conditions 
yield per 
plot in pared with 
acre 
continuous fertilizers, 
culture in effecting 
larger 
yields 
Pounds 
Crop rotation without the use of fertilizer (r)__ 1,621 
Use of fertilizer without rotation (/) 1,816 
No rotation and no fertilizer 1,321 
Per cent 
300 60. 6 
495 
