CONTENTS 



CHAPTER PAGE 



XXIV. MINNESOTA SOIL INVESTIGATIONS ...... 499 



XXV. CANADIAN FIELD EXPERIMENTS 505 



XXVI. SHORT-TIME POT-CULTURE AND WATER-CULTURE EXPERIMENTS 



IN COMPARISON WITH FIELD RESULTS 513 



PART IV. VARIOUS FERTILITY FACTORS 



XXVII. MANUFACTURED COMMERCIAL FERTILIZERS . . . . 517 



XXVIII. CROP STIMULANTS AND PROTECTIVE AGENTS .... 533 



XXIX. CRITICAL PERIODS IN PLANT LIFE 538 



XXX. FARM MANURE 541 



XXXI. LOSSES OF PLANT FOOD FROM PLANTS 549 



XXXII. LOSSES OF PLANT FOOD FROM SOILS 556 



XXXIII. FIXATION OF PLANT FOOD BY SOILS- 562 



XXXIV. ANALYZING AND TESTING SOILS 565 



XXXV. RELATION OF FERTILITY TO APPEARANCE OF SOILS OR CROPS . 572 



XXXVI. FACTORS IN CROP PRODUCTION 5715 



XXXVII. ESSENTIAL FACTORS OF SUCCESS IN FARMING .... 584 



XXXVIII. THE VALUE OF LAND 586 



XXXIX. Two PERIODS IN AGRICULTURAL HISTORY ... . 1590 



APPENDIX 



SECTION 



I. THE PRODUCTION OF PHOSPHATE ROCK 595 



II. MODEL FERTILIZER LAW 599 



III. COMPOSITION OF ANIMAL AND PLANT PRODUCTS 602 



IV. STATISTICS OF AGRICULTURAL PRODUCTS 605 



V. METHODS OF SOIL ANALYSIS 626 



VI. COMPOSITION OF SOME EUROPEAN SOILS 634 



VII. AGRICULTURAL COLLEGES AND EXPERIMENT STATIONS IN THE UNITED 



STATES AND CANADA 643 



INDEX 647 



