Soil :  the yearbook of agriculture / 
United States Department of agriculture 
 - Washington, DC :  U.S Government,  1957 
 - xiii, 780 p. :  ill. ;  23 cm. 
<br/><br/> CONTENTS<br/><br/>Principles<br/>the basis of fertility<br/>what soils are<br/>physical properties<br/>growth of plants<br/>e.tc<br/><br/>Fertility<br/>plant nutrition and soil fertility<br/>nitrogen and soil fertility<br/>soil phosphorous and fertility<br/>e.tc<br/><br/>Practices<br/>how to determine nutrient needs<br/>soil reaction and liming<br/>trends of fertilizers<br/>materials and mixtures<br/>e.tc<br/><br/>Soil care<br/>principles of tillage<br/>saline and alkali soils<br/>erosion on cultivated land<br/>e.tc<br/><br/>Moisture<br/>conserving soil moisture<br/>irrigation in arid regions<br/>e.tc<br/><br/>Systems<br/>cropping systems and soil<br/>the use of soil maps<br/>three farming systems<br/>e.tc<br/><br/>Regions<br/>Special uses<br/> 
<br/><br/>Includes index 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Soil
<br/><br/><label>Dewey Class. No.: </label>630.5  / SOI