XXX CONTENTS. 



CHAPTER XXV. ON THE VALUATION AND ANALYSIS 

 OF MANURES. 



Value of chemical analysis ....... 539 



Interpretation of chemical analysis . . . . . .539 



Nitrogen . . . . . . . . . . 540 



Phosphoric acid ......... 541 



Importance of mechanical condition of phosphate . . 542 



Potash 542 



Other items in the chemical analysis of manures . . . 543 



Fertilisers and Feeding Stuffs Act ...... 543 



Different methods of valuing manures . . . . . 544 



Unit value of manurial ingredients ...... 544 



Intrinsic value of manures ....... 545 



Field experiments 545 



Educational value of field experiments ..... 547 



Value of manures deduced from experiments .... 548 



Value of unexhausted manures ...... 549 



Potential fertility of a soil 549 



Tables of value of unexhausted manures ..... 551 



APPENDIX TO CHAPTER XXV. 

 NOTE 



I. Factors for calculating compounds from manurial in- 

 gredients . . . . . . . . . 553 



II. Units for determining commercial value of manures and 



cash prices of manures 554, 555 



III. Manurial value of nitrogen and potash in different sub- 



stances .......... 556 



IV. Comparative manurial value of different forms of nitrogen 



and potash ......... 557 



V. Lawes' and Gilbert's tables for calculating unexhausted 



value of manures ........ 559 



CHAPTER XXVI. THE ROTHAMSTED EXPERIMENTS. 



Nature of experiments on crops and manures . . . .561 

 Soil of Rothamsted 561 



Table I. List of Rothamsted field experiments . . .562 



Wheat experiments 



Unmanured plots 562 



