0/5 SOILS 



tion prevails, the denitrifying bacteria are most abundant 

 and active ; hence, there is a constant loss of nitrogen 

 from the soil something certainly most undesirable. 



Poor tillage, bad aeration, and improper physical treat- 

 ment are favorable to the denitrifying bacteria but un- 

 favorable to the nitrifying bacteria. 



Good tillage retards the action of the harmful bacteria 

 and at the same time accelerates the working of the 

 beneficial ones a most important reason why tillage 

 never should be neglected. 



The increase of the water-holding content of the soil. 

 Tillage assists soils in securing and in holding water in 

 the following ways : By opening the surface crust so that 

 water may enter the soil more freely, and by hastening 

 percolation that the subsoil may receive more water. 



When the surface crust has been opened by tillage 

 tools, water finds lodgment until it gradually sinks into 

 the soil, a most excellent way of preserving what might 

 be lost otherwise. Tight-bound soils, with^ unbroken sur- 

 faces, secure no great amount of water, often not enough 

 for its many needs. Soils, like the stiff clays, are enabled 

 to secure much more water and to hold it also, if subsoiled 

 and fall-plowed. Indeed, this is a splendid treatment to 

 give such lands, although subsoiling is quite costly. 



Of course, tight-bound soils that have little air space 

 in them, and whose particles are closely pressed together, 

 permit slow descent only to all water passing downward. 

 This is a condition certainly not desirable, and may be 

 remedied and improved in this respect by deep-stirring 

 agencies that open and stir and mellow at depths not 

 reached by ordinary surface tillage. Our leguminous 

 plants are wonderful helpers in this difficulty. 



It is also important to have the soil mellow and fine, 

 thereby increasing both the number of particles in the 



