XX TABLE OF CONTENTS 



PAGES 



age of irrigated and aikaii lands, 561 — Vertical drainage, 

 562 — Drainage by means of explosives, 563 — R(?sum^, 

 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, 560 — Pulverizing action of the plow, 570 



— Types of plows, 571 — Shapes of moldboard plows, 

 572 — Position of the furrow slice, 673 — 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, 683 — Rollers, 584 — Clod 

 crushers, 585 — EiScient 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, 690 — 

 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, 696 — Preparation of 

 land for irrigation, 597 — Methods of applying water, 

 698 — Overhead sprays, 699 — 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. 



Dr]/ Farming* 



Practices in dry farming, 610 — Storage of water in 

 the soil, 611 — Conservation of moisture, 612 —-Alternate 

 cropping, 613 —- Drought-resistant crops, 614 — Soils 



