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 POSITIVE REASONS FOR ROTATION IN HUMID AREAS Continued. 



(c) To maintain an equilibrium in the humus supply. 



(d) To matniain an equilibrium in the labor con- 

 ditions. 



2. NEGATIVE REASONS FOR ROTATION IN HUMID AREAS 385 



(a) To prevent the undue accumulation of weeds. 



(b) To prevent the undue increase of insects. 



(c) To prevent undue increase in fungous diseases. 



(d) To prevent the shifting of soils by water and 

 winds. 



3. INCIDENTAL BENEFITS FROM ROTATION 388 



(a) Reducing the hazard from crop failure. 



(b) The more complete maintenance which it brings. 



(c) The wider diversity in live stock production which 

 it gives. 



(d) The salutary influence which it exerts on markets. 



4. ADDITIONAL REASONS FOR ROTATIONS IN DRY AREAS. . . . 390 



(a) To prevent the loss of moisture that does not 

 enter the soil. 



(b) To prevent the loss of moisture in the soil. 



(c) To increase the moisture content in the soil. 



(d) To make farming possible and profitable. 



5. ROTATION BY ALTERNATING FALLOW AND GRAIN 392 



(a) How such rotation is conducted. 



(b) The benefits from such rotation. 



(c) The area for such rotation. 



(d) The objections to such rotation. 



6. ROTATIONS BY ALTERNATING CULTIVATED CROPS AND 

 GRAINS 395 



(a) How such rotation is conducted. 



(b) The benefits from such rotation. 



(c) The area for such rotation. 



(d) The objections to such rotation. 



7. ROTATION WHICH COMBINES FALLOW AND CULTIVATED 

 CROPS 397 



(a) How such rotation is conducted. 



(b) The benefits from such rotation. 



(c) The area for such rotation. 



(d) The objections to such rotation. 



8- ROTATIONS WHICH INCLUDE GRASS CROPS 399 



(a) How such rotation is conducted. 



(b) The benefits from such rotation. 



(c) The area for such rotation. 



(d) The objections to such rotation. 



9. ROTATION THAT SHOULD NOT BE FOLLOWED 401 



(a) Growing small grains in a long succession. 



(b) Growing pastures for many successive years. 



(c) Growing alfalfa for many successive years. 



(d) Growing small grains except on cultivated land. 



