APPENDIX 635 



(in two million) of phosphorus soluble in cold hydrochloric acid are in 

 need of phosphorus fertilizer (" ersatzbedurf tig in Phosphorsaure"). 



The compiled data from France include about 1550 soil analyses, but 

 here also only the plant food dissolved by the acid used is reported, and 

 no information is given concerning the strength of acid, time, or tem- 

 perature. While these results may have some value for purposes of 

 comparison among themselves, they are of little or no value for compari- 

 son with the total amounts of plant food contained in other soils. Fur- 

 thermore this great mass of data relates to the soil of only a few prov- 

 inces. There are in all eighty-seven different provinces, or counties, in 

 France, and 705 of the soil samples reported upon were collected in the 

 one province of Aisne, while 674 others were collected in Pas-de-Calais 

 and Loire-Inferieure, and 129 more in three other provinces. The 

 remaining 42 samples represent six additional provinces, leaving seventy- 

 five provinces from which no soil analyses are reported. Practically 

 all of the 1550 soil samples were evidently collected about 1890 or 

 before, and no information is given in the compiler's report to show 

 whether they are supposed to represent good land or poor land, although 

 in one case a single field is represented by analyses of 73 samples of soil. 



In considering the analyses of European soils, it may well be kept in 

 mind that there are still to be found areas of "abandoned" land even in 

 western Europe, and chemical analyses of these soils are often made 

 before attempting to bring them back into agricultural use by means 

 of fertilizers and manures. Thus the marked differences in the plant- 

 food content of different soils in England may serve best as an index 

 of the agricultural history of the farms with respect to the past use of 

 bones, guanos, phosphates, etc., while in America such differences apply 

 not so much to individual farms, fields, or plots (see Table 73, page 411), 

 but rather to types of soil more or less modified in the older States by 

 the general and almost invariable practice of gradual soil depletion. 



The data showing the phosphorus content of soils from Great Britain 

 make a contribution of probable value, (i) because approximately the 

 total amount is reported, and (2) because the soil formation is frequently 

 recorded. In the case of Dorset County, the samples appear to have 

 been collected in connection with some sort of systematic survey or 

 classification, as indicated by the records and also the reference: "Fifth 

 Annual Report on the Soils of Dorset, University College, Reading, 

 1003." 



The compiler has combined the calcium found in limestone (cal- 

 cium carbonate) with that reported in other forms, so that the calcium 

 data have too little value to justify their reproduction here. It may be 



