CONTENTS. 7 



Department Bulletin No. 494. — A Humidifier for Lemon Curing 



Rooms — Continued. Page. 



Construction of the humidifier fi 



Operation of the humidifier '.."*. 7 



Other uses of the humidifier 9 



Results 10 



Summary 10 



Department Bulletin No. 495. — Spray Irrigation: 



Introduction 1 



Economic conditions justifying spray irrigation 2 



Farm conditions adapted to spray irrigation 5 



Amount of water required for spray irrigation '. . . 5 



Development of water supplies fi 



Screening water 12 



Types of spray irrigation systems 14 



Stationary-nozzle spray systems ' 15 



Stationary-overhead spray systems 18 



Types of pumps for spray irrigation 25 



Designing of spray irrigation systems 29 



Designing of pumping plant 32 



Outline of procedure for installing spray irrigation systems 35 



Cost data 37 



Department Bulletin No. 496. — Investigations of the Rotting of Slash 

 in Arkansas: 



Introduction 1 



Methods of brush disposal 2 



White-oak slash 3 



Blaok-oak and post-oak slash 7 



Short leaf-pine slash 7 



The growth of wood-rotting fungi ; . . . 9 



Why brush in the center of the pile does not rot 10 



General discussion 11 



Summary 14 



Department Bulletin No. 497. — Tests of Western Yellow Pine Car Sills, 

 Joists, and Small Clear Pieces: 



Introduction 1 



Material tested 2 



Methods of test .' 3 



Strength values shown by the tests 4 



Comparison of results of tests on large and small pieces 5 



Relation between strength values 6 



Relation between physical characteristics arcl mechanical properties .... 6 



Seasoning 1 ] 



Effect of seasoning upon strength 1] 



Conclusions 15 



Department Bulletin No. 498. — Experiments with Spring Cereals at the 

 Eastern Oregon Dry-farming Substation, Moro, Oreg.: 



Introd uction 1 



Description of the station 2 



Experimental methods 11 



"Cereal experiments 14 



Summary 36 



Department Bulletin No. 499. — The Mtjlched-basin System of Irrigated 

 Citrus Culture and Its Bearing on the Control of Mottie-leaf: 



Introduction 1 



Cultural practice in the citrus districts of California 3 



Plowsole 4 



Organic mulching 4 



The mulched basin 6 



Moisture determination in the Sunny Mountain Grove 7 



Soil-moisture measurements in basins, under cover crops and under a soil 



mulch in the Vivienda Grove ; 8 



Basin and cover-crop experiments in the Vic toria Grove 11 



Furrow irrigation often not adequate 13 



