68 CULTIVATION AND TILLAGE 



should be attended to at once, because if it is delayed many 

 circumstances may arise to hinder the work. 



Tillage is the most efficient means of assisting nature in 

 converting the plant food into forms that are available 

 to the plants. One of the most noticeable results of cultiva- 

 tion is the fineness of the soil particles which is accomplished 

 by the breaking up of the larger lumps. This pulverization 

 of the soil is very beneficial, because it makes it easier for 

 the roots of the plants to penetrate to a greater depth and 

 to feed over a larger area. The tender rootlets must push 

 their way in between the soil grains, because it is impossible 

 for them to penetrate hard lumps of soil, and where large 

 clods of earth are abundant the growth of the plants is 

 materially checked. 



Objects of Cultivation. — Some of the reasons for cultiva- 

 tion may be summed up briefly as follows: (1) Cultivation 

 reduces the soil particles to a fine state of division, which 

 modifies its physical make-up. This pulverization of the 

 soil particles is highly important in that plant growth 

 demands a soil that is fine because it usually will be able 

 to hold more water. (2) Cultivation helps to regulate the 

 water-holding capacity of the soil. This is brought about 

 by the greater number of soil particles which are found in 

 a given area. Since the amount of water that a soil can 

 hold is determined by the film of water that surrounds 

 each soil particle, it is evident that the greater the number 

 of soil particles that occupy a given space, the greater will 

 be the amount of water that it can hold. (3) Cultivation 

 modifies the soil temperature: When air is permitted to 

 permeate the soil, it carries with it heat and warmth to a 

 lower depth. The heat units entrapped in the soil causes 

 the temperature to be higher and the growth to be more 

 rapid. (4) Cultivation stimulates the increased production 

 of beneficial bacteria. (5) Cultivation aerates the soil. If 

 the soil particles are stirred around, and finely broken up, 

 there is bound to be a greater number of soil spaces, and 

 consequently there must be more air, since the space 

 between each soil particle is necessarily filled with air. (6) 

 Cultivation destroys weeds. (7) Cultivation prevents the 



