vi PREFACE 



land nominally in farms has not yet been called 

 on to produce food. There are swamps to be 

 drained, cut-over forests to be cleared, deserts 

 to be watered, and dry lands to be made pro- 

 ductive by specialized crops and methods. 

 Without increasing the efficiency of its im- 

 proved acres, the nation still possesses enough 

 resources in terms of land alone to feed double 

 the population that exists to-day. It has been 

 the author's endeavor to chart this empire of 

 opportunity that awaits the gleaner in the 

 period of reclamation which is now setting to- 

 ward flood tide. 



The problem of the fertility of the soil is 

 one of national importance; it determines not 

 only the fortunes of the farmer in the field, 

 but, in the end, the life of the nation. For gen- 

 erations past, agricultural literature has been 

 buried under a theory of doom imposed by a 

 great chemist, Liebig, which teaches that the 

 resources of the soil are as definite as cash in 

 a bank or coal in a mine. Under this orthodox 

 theory which actuates the machinery of the 

 greater part of agricultural education as it 

 exists to-day, the farmer must feed the soil if 

 he would have the soil continue to feed him. Fail- 

 ing this, it has been variously computed that 



