COXTliXTS. 



Page. 



Introduction 7 



Location and general description of the region 



Experiments in dry farming in the Great Basin 11 



Private experiments in dry farming 13 



The Utah arid experiment farms 14 



Local conditions which affect dry farming 15 



Precipitation mainly in winter 16 



Annual variation in rainfall 18 



Influence of local topography on rainfall 20 



Methods of interseason tillage 22 



Maintenance of a clean summer fallow 24 



The importance of soil texture 25 



Crops and crop tillage 27 



Tillage for wheat 28 



Tillage for alfalfa 29 



Thin seeding essential to best results 30 



The sustained productiveness of dry-farmed soils 31 



The heavy soils not leached : 32 



The importance of organic matter in the soil 33 



Conditions favoring nitrification 33 



The fixation of nitrogen 34 



Organic matter lost by oxidation 35 



Dry farming supplementary to irrigation 35 



Making a home on the dry lands 36' 



Summary 38 



Description of plates 40 



Index 41 



103 5 



