CHAPTER XVII 

 SOIL WATER 



THE more important tillage tools and tillage op- 

 erations we studied in Chapters XI and XII. They 

 will be noticed here only in connection with their 

 influence over soil water, for in the regulation of 

 this important factor in soil fertility the other con- 

 ditions of fertility are also very largely controlled. 



IMPORTANCE OF SOIL WATER 



" Of all the factors influencing the growth of 

 plants, water is beyond doubt the most important," 

 and the maintaining of the proper amount of soil 

 water is one of the most important problems of the 

 thinking farmer in controlling the fertility of his 

 soil. 



NECESSITY OF SOIL WATER 



The decay of mineral and organic matter in the 

 soil, and the consequent setting free of plant food, 

 can take place only in the presence of moisture. 

 The plant food in barn manures and crops plowed 

 under for green moisture, can be made available 



