XX 



TABLE OF CONTENTS 



age of irrigated and alkali lands, 561 Vertical drainage, 

 562 Drainage by means of explosives, 563 Re'sume', 

 564. 



CHAPTER XXIX 



TILLAGE 663-681 



Objects of tillage, 565 Implements of tillage, 566 

 Effects on the soil, 567 Classes of tillage implements, 

 568 Plows, 569 Pulverizing action of the plow, 570 

 Types of plows, 571 Shapes of moldboard plows, 

 572 Position of the furrow slice, 573 Depth and 

 width of furrow, 574 Plow sole, 575 Hillside plow, 

 576 Covering rubbish, 577 Subsoil plow, 578 

 Cultivators, 579 Cultivators proper, 580 Leveler 

 and harrow types of cultivator, 581 Seed cultivators, 

 582 Packers and crushers, 583 Rollers, 584 Clod 

 crushers, 585 Efficient tillage, 586. 



CHAPTER XXX 



IRRIGATION AND DRY FARMING . 



, 682-717 



Relation of irrigation to rainfall, 587 Extent of irri- 

 gated land, 588 History of irrigation, 589 Develop- 

 ment of irrigation practice in the United States, 590 

 Irrigation in humid regions, 591 The Reclamation 

 Service, 592 Legal, economic, and social effects of 

 irrigation, 593 Divisions of irrigation, 594 Source of 

 water for irrigation, 595 Canals, 596 Preparation of 

 land for irrigation, 597 Methods of applying water, 

 598 Overhead sprays, 599 Subirrigation, 600 

 Methods most used in arid regions, 601 Flooding, 602 



Furrows, 603 Size and form of furrows, 604 Unit 

 of measurement, 605 Amount of water to apply, 606 



Time to apply water, 607 Conservation of moisture 

 after irrigation, 608 Sewage irrigation, 609. 



Dry Farming. 



Practices in dry farming, 610 Storage of water in 

 the soil, 611 Conservation of moisture, 612 Alternate 

 cropping, 613 Drought-resistant crops, (514 Soils 



