Mallee - Part 2

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sorption more difficult. Instead of adopting any particular standard for salts, therefore, the plan has been followed at Esperance of taking a number of soil samples from growing crops, from bush lands adjacent to growing crops, and from crops apparently damaged by salt with a view to obtaining experimental data applicable to the district, and for the purpose of this inquiry.

It will be convenient to look first at those analyses of soils under crop before proceeding to the consideration of bush lands of untried value and unknown composition.

                                                                                             Location of Soil Samples.

Samples were taken at 20 places in the Esperance-Norseman district. The samples were numbered and the location of each is marked with the sample number on the accompanying plan (Appendix A). Care was taken in sampling to select types which were. proportionately representative. At each location samples were always taken in successive depths of one foot down to three feet, making 60 samples in all. The surface foot of each number is marked "A," the second foot "B," and the third foot "C." In addition to the Esperance samples soils were also taken at four places at Kellerberrin, Meckering, and York.

                                                                                         Analysis of the Soil Samples.

The samples were submitted to the Acting Government Analyst on 15th November along with the following letter:—

The University, Perth, 15th November, 1916.

Acting Government Analyst, Perth.

Dear Sir,—I am sending herewith 71 samples of soil for analysis by direction of the Royal Commission on Esperance lands.

The samples have been taken from lake bottoms, bush lands, and lands carrying crop in the Esperance district, and some of them from cropped lands in other parts of the State.

It will be sufficient to determine the amount of water-soluble salts only, and the ordinary chemical analysis for agricultural purposes is not required. Please estimate, therefore, from the water extracts of the soils:— (1.) Total inorganic salts. (2.) Chlorine. (3.) Sulphuric Acid. (4.) Carbonic acid as carbonates.

For the convenience the items (2), (3), and (4) may be stated in their equivalents of chloride, sulphate, and carbonate of sodium, and in this form given as percentages of the dry soil.

The above determinations are required for all of the samples. In addition please estimate in the water extract the percentages of lime (CaO) and magnesia (MgO) in the samples marked 1A, 2A, 9A, and 18A.

The chemical reaction of each soil might be noted.

Along with the soils I am also forwarding 10 samples of waters. In these it will be sufficient to determine the percentage of chlorine.

the Commissioners are desirous of presenting their Report at the earliest possible date, and it is requested, therefore, that the above analyses be treated as a matter of urgency.

Yours faithfully, (Sgd.) JOHN W. PATERSON.

P.S.—Please reserve such portion of the samples as you do not use in case additional determinations should be asked for later.—J.W.P.

Certain determinations were asked, but no instructions were given as to how the analyses should be conducted. This was left to the Analyst. The information asked for was received from Mr E. A. Mann, Government Analyst (who had returned to Perth), on 6th January. The results of Mr Mann's analysis are given in Table 1. of Appendix A.

Subsequently, in giving evidence tot he Commission on 11th January, Mr Mann disclaimed responsibility for his figures relating to "sulphuric acid" and to "carbonic acid as carbonates," chiefly on the ground that those items were calculated into their sodium salt equivalent. It is sufficient to say that my request for certain information to be stated in a certain form did not affect the analytical process, that it was quite usual, and followed a recent American practice in similar investigations. It was also doubtful from the evidence given whether in determining "carbonic acid as carbonates" the analyst had determined the constituent asked for. In the circumstances I was reluctantly compelled to ask the Commission to have duplicate analyses made elsewhere. The need was the more regrettable in that it delayed the presentation of a report.

When the samples had been forwarded tot he Acting Government Analyst, sufficient material was retained to furnish two further sets of duplicate samples of the same soil. Some of these were now submitted to two independent analysts of established reputation. One set of 36 samples was forwarded to Messrs. Dunn & Son, F.C.S., and B.Sc., Melbourne, and another set of the same 36 along with other four of the original soils was forwarded to Mr E. S. Simpson, B.E., B.Sc. F.C.S., of the Geological Department, Perth. These 40 samples represented the more important of the 71 samples originally taken, and as Mr Mann's figures for common salt in the additional 31 samples examined by him had not been questioned, this most important constituent was known in the remaining samples. The covering letter sent to Messrs. Dunn was similar to that originally sent to the Government Analyst's Department, except that lime and magnesia were asked in all the samples instead of in four only. The letter to the Geological Department was similar to that sent to Messrs. Dunn, except that in four of the samples, nitric acid, potash, and soda were asked in addition. As before no instructions were given regarding analytical methods in making the determinations required.

The results obtained from Messrs. Dunn, Melbourne, are detailed in Table II., and those from Mr E. S. Simpson, of the Geological Department, in Table III. of Appendix A.

                                                                                     Comparison of the results.

In making requests for certain determinations no methods of analysis were recommended, it being thought that the best work would be obtained by each analyst following the methods he was accustomed to. In the absence of standard methods each analyst adopts the means he considers best, and while this regime continues nothing like absolute uniformity is to be expected in the results of soil analyses. For example, in soil salt analyses the relative amount of soil and water used while extracting the salts and the length of time during which the water remains in contact with the soil have some influence upon the results. To provide information upon this point, Messrs. Dunn have kindly provided me with the results of a test which they carried out with Mark 5A (No.4) of the Esperance soils—using 100 grains soil:—

                                                                                                       TABLE 1.
                                                                  Effect of time and quantity of water on salts extracted.

___________________________________________________________________________________________________________________ Vol. of Water. Time of Contact. Inorganic Salts. CO3. HCO3. C1. SO3. CaO. MgO. ___________________________________________________________________________________________ c.c. hrs. 300 48 •0357 Nil •0120 •0078 •0078 •0042 •0012 500 48 •0493 Nil •0183 •0078 •0100 •0035 •0010 300 96 •0456 Nil •0130 •0059 •0082 •0054 •0015 ____________________________________________________________________________________________