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has a fair reserve of potash and phosphates, but not much to spare: No. 

 2 has about double that quantity in reserve, and is therefore satisfactorily 

 supplied: No. 3 is just on the border of potash-poverty, but has a 

 moderate supply of phosphoric oxide. Judging, by Method V., of the 

 immediate availability of these constituents, No. 2 again is satisfactory 

 both in potash and lime, No. 1 has about half the proportiona of each, 

 and No. 3 is particularly weak in phosphates. In each of these three 

 soils the proportions of potash extracted by Method V. was about one- 

 sixth that extracted by Method I., and in two cases out of the three the 

 latter method gave about three times as much phosphoric oxide as the 

 former. 



Of the four Robertson soils, Nos. 21, 22, 23 and 24, No. 23, which 

 proved the best when examined by Method I., also turned out the best 

 when extracted by Method V., but all of them are lacking in reserve of 

 phosphates when judged on the basis of the former method, and in im- 

 mediately available phosphates on the basis of the latter method. 

 Method V. extracted from one-sixth to one-third as much potash, and from 

 one-sixth to one-twelfth as much phosphoric oxide as the standard method. 

 The lime extracted by Method V. was practically the same in amount 

 as that taken out by Method I., indeed, strange though it may seem at 

 first sight, in two cases, Nos. 21 and 22, the citric acid method extracted 

 slightly more lime than the Hydrochloric acid method. This is ex- 

 plained by the fact that the lime in the soil consists chiefly of carbonate 

 and so dissolves readily in either acid, and that the soil sifted through 

 the 3 m.m. sieve, for the purpose of Method V., would contain a larger 

 proportion of the coarser grades than the Jm.m. product used for Method 

 I., and hence more calcium carbonate, since the coarser particles in this 

 case consisted almost wholly of that material. 



