7. Why must millions be spent to keep our harbors from filling 

 with silt? 



8. Why 'do streams wander here and there, far more than they 

 did under virgin land conditions, changing course, altering 

 field patterns and property lines ? 



9. Why do new. industries often avoid many seemingly desirable 

 locations ? 



10. Why does the fertility of sloping land decrease several times as 

 fast as mere cropping should cause ? 



13. Why are nutrient minerals, not long ago found near the sur 

 face, now found beyond the reach of roots? 



12. Why are millions of acres of once rich soils now gashed, gullied, 

 or skinned down to a whiskery covering of weeds? 



13. Why is the humus content of the nation's soils falling? 



14. Why is the cost of meat so high ? 



15. Why do we reclaim arid lands at such high cost? 



10. Why do we have so much trouble with weeds, almost none of 

 which the pioneer knew? 



17. Why do livestock on a vast total of forage acres now require, 

 per animal, from three to six times the former area for sup- 

 port? 



13. Why do great stretches of former hardwood forest areas refuse 

 to produce hardwoods today? 



^19. Why do we maintain national forests at a cost which is double 

 the value of the harvested timber? 



20. Why is the cost of lumber so high ? 



21. Why does the hunter complain of lack of game? 



22. Why does the fisherman moan? 



23. Why are marine fish and shellfish scarce and high priced? 



24. Why do large areas have only half or a fourth the number of 

 insects, especially bees, necessary for full crop pollination? 



25. Why are plant diseases so prevalent and costly? 



26. Why are nutritional deficiencies prevalent among domestic 

 animals and the human clan ? 



27. Why do we have rural slums ? 



AS WE SHALL DEMONSTRATE 



The answer, in whole or in part, directly or indirectly, to all these 

 questions is: plant deficiency. The deficiency is, for most of them, a 

 matter of quantity. Or, the quantity may be adequate for only part 

 of the time, part of the j'ear or period of years. The deficiency may 

 also be one of quality ; that is, a deficiency in the amount or number of 

 nutrients composing the plant parts. Very often the quantity of 

 plants cannot be increased without also providing for better quality. 

 Plant qualit}' is of greater importance than most of us realize. 



xiii 



