CULTIVATION AND IRRIGATION 67 



CULTIVATION AND IRRIGATION. 



CHAPTER V. 



RACTICALLY all the cultivation of a potato crop 

 is done before they are up, although the growing 

 plants need a great amount of thorough cultiva- 

 tion. Cultivation is not only for the purpose of 

 loosening the soil, therefore conserving the moisture, but 

 for the killing of weeds and germs as well, and allowing the 

 sun, heat, and air to penetrate the soil, thus causing the de- 

 composition of the fertilizers and allowing the tubers the 

 ideal conditions they require during formation. The thorough 

 cultivations warm the soil and cause a deeper root system. 

 Therefore cultivation increases producing power, by retain- 

 ing the moisture, making the plant food available, allowing a 

 circulation of air to pass about the forming tubers, and kill- 

 ing the weeds, thus allowing the plant food that would be 

 uselessly wasted to go toward making a better crop. 



Level cultivation generally proves more satisfactory 

 that is, where the climate and soil conditions are favorable. 

 However, where irrigation must be practiced, the hill cul- 

 ture or ridge system is used. Level cultivation is practiced 

 where the soil is of a naturally moist nature, or in soils where 



