CHAPTER X 



TILLAGE 



Need for tillage. There are certain factors in crop pro- 

 duction that man can do little to change. The range of 

 temperature, the make-up of the air, the amount and time 

 of rainfall, and the amount of sunlight are beyond his power 

 to vary ; but the soil, fully as important as any of these, may be 

 greatly modified by his efforts. By drainage he adds to its 

 depth and warmth, by the addition of manures he enhances 

 its fertility, and by proper cultivation he promotes the develop- 

 ment of the plants growing in it. Given warmth, moisture, and 

 fertility, tillage is still necessary for the highest development 

 of growing plants. Even wild species become more luxuriant 

 and give finer flowers and better flavored fruits when properly 

 cultivated. The chief difference between our food plants and 

 others of the same kind growing wild is due to the fact that the 

 soil about the food plants is tilled. Tillage renders the soil less 

 compact, enables the roots of plants to penetrate it more easily, 

 adds to its ability to absorb rainfall, prevents the escape of 

 moisture already in the soil, assists the air to penetrate more 

 deeply, thus adding to its warmth and promoting weathering, 

 distributes the bacteria, and discourages the weeds by prevent- 

 ing their becoming established. The great amount of pore space 

 which tillage adds to the soil may be realized by digging a hole 

 in any piece of ground and then endeavoring to put back into 

 the hole all the soil removed. Wherever trenches are dug for 

 pipes or tiling we see an amount of soil left over that, in spite 

 of soaking with water and ramming with heavy instruments, 

 cannot be returned to the trench from which it was dug. 



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