xviii INTRODUCTION 



which they are doing everywhere, they can also understand their 

 own business, if they will, when they remain on the farm or in 

 control of land. 



Technical books are to be studied; they are not written for en- 

 tertainment. They furnish definite facts, accurate data, and 

 necessary information, relating to underlying principles upon which 

 permanent successful practice must be based. 



The most important material problem of the United States is to 

 maintain the fertility of the soil, and no extensive agricultural 

 country has ever solved this problem. The frequent periods of 

 famine and starvation in the great agricultural countries of China, 

 India, and Russia, and the depleted lands and abandoned farms 

 of our own eastern United States are facts that serve as a constant 

 proof that the common practice of agriculture reduces the produc- 

 tive power of land. 



The rule is almost universal that old land is less productive than 

 new land. This simple and well-recognized fact points inevitably 

 toward future poverty, not only for the individual or the family, 

 but likewise for the commonwealth and for the nation. We may 

 ignore this if we choose in America for a few more years, but with 

 the decreasing productive power of our lands and with a rapidly 

 increasing population the truth must strike us in the face in the 

 near future. 



We cannot afford to let ignorance, prejudice, or bigotry blind us 

 in this matter, neither in ourselves nor in others. Even the confi- 

 dent assurance, by those who live in continued plenty, that the 

 people of earth are not destined to suffer hunger, does not remove 

 the positive fact that thousands, and sometimes millions, of people 

 actually die of starvation within a single year in some of the old 

 agricultural countries. 



An early recognition of these world-wide conditions and tend- 

 encies is of paramount importance to the people controlling the 

 more productive lands of the United States, not only for their own 

 sake, but also for the sake of others who are dependent upon those 

 lands for their present and future support, whether engaged directly 

 in agricultural pursuits or in other industrial or professional lines, 

 which cannot exist and prosper without agriculture. 



If the art of agriculture has ruined land, the science of agricul- 



