Mallee - Part 2

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This transcription is complete

are shown on photographs handed to the Commission may be summarised briefly as follow:—

(1.) York Soil.—Germination delayed and growth affected by .053 per cent. of salt; germination similarly delayed and growth further affected by .093 per cent. of salt.

(2.) Pingelly Soil.—Germination reduced 22 per cent. by .063 per cent. of salt; germination delayed one week and reduced 28 per cent. by .113 per cent. of salt; germination delayed 10 days and reduced 44 per cent., and growth greatly diminished by .163 per cent. of salt.

(3.) Kellerberrin Soil.—Germination delayed and reduced 10 per cent. and growth seriously affected by .126 per cent. of salt; germination further delayed and reduced 30 per cent. and growth still further affected by .176 per cent. of salt.

Summary.—Germination affected by .053 per cent., reduced 44 per cent. by .163 per cent.; growth affected by .053 per cent., very seriously affected by .163 per cent. of salt.

(C).—Department of Agriculture, New South Wales, conducted a series of experiments, which were published in Bulletin No. 7, December, 1912. They were conducted by Mr. Maiden, Director of the Botanic Gardens in Sydney, in conjunction with Mr. F. B. Guthrie, agricultural chemist in New South Wales. Results summarised show:—

Germination affected—.05 per cent. common salt.

Germination prevented—.2 per cent. common salt.

Growth affected by—.05 per cent. to .15 per cent. common salt.

(D).—Hilgard, the famous American authority, has been quoted specially by Mr. O'Brien in criticism of my standard, but he has either misunderstood or misread the authority. Hilgard, in his book on Soils, page 464, states:—

The maximum for cereals may be approximately stated to be .25 per cent. for common salt (as quoted by Mr. O'Brien).

But the context clearly shows that this means the quantity which will actually prevent crops, and it must be noted that it also includes all cereals, of which Hilgard shows that barley is 4½ times as resistant as wheat. On this basis the maximum for wheat would be .05 per cent. This is brought out more clearly when studying the complete table of figures (given by Hilgard on page 467 of his book), compiled by Dr. R. H. Loughridge of the California Experimental Station, mainly from his own observations. In this table the highest percentage of salt by which wheat is unaffected is .007 per cent. And again on page 76 of his book Hilgard states that common salt is "to be considered" as an injurious ingredient of cultivable soils whenever present to a larger extent than a few hundredths of 1 per cent., while .25 per cent. renders the land unfit for most culture plants."

Note.—As .05 per cent. is five-hundredths of 1 per cent., it is seen that Hilgard's standard agrees with mine.

(E).—Bayley's Cyclopedia is quoted by Mr. O'Brien—the original authorities from which this book quotes are not stated so as to enable reference, but some of the figures are apparently based upon Kearney's work, which was been rejected as unreliable, because the experiments instead of being conducted in soils were carried out in solutions of various salts.

(F).—Publication of United States Department of Agriculture Experiment Station Work No. 10, Farmers' Bulletin No. 97, page 9, puts the limit of common salt allowable for wheat as—

In solution—.4 per cent.

In the soil—.1 per cent.

This illustrates the unreliability of solution tests indicated in "(E)."

(G).—Kearney & Cameron, quoted by Mr. O'Brien. The source from which Mr. O'Brien quotes his figures cannot be found, and the nature of the salt is not stated nor the conditions of experiment prescribed. The figures quoted are so abnormal (being eight times as high as the highest figures given by Hilgard) that there is probably some error of statement. This is the only authority quoted which cannot be refuted owing to the absence of reference.

(H).—Some of the most complete and most recent work is that done by F. S. Harris, Professor of Agronomy, Utah Experiment Station, as published in his paper, Effect of alkali salts in soils on the germination and growth of crops—Journal of Agricultural Research, 4th October, 1915.

Extracts from his paper: Table 1, page 5—

.05 per cent. common salt gave only 90 per cent. germination.

.01 per cent. common salt gave only 60 per cent. germination.

.2 per cent. common salt gave only 40 per cent. germination.

The height was unaffected by the above quantities at 9½ inches. The .2 per cent. marked the limit of growth for wheat.

Table 6, page 9 shows the following results in another series:—

Germination reduced by 12 per cent. with .08 per cent. common salt.

Germination reduced by 50 per cent. with .3 per cent. common salt.

Germination entirely ceased with .6 per cent. common salt.

Table 16, page 46 shows delay in germination caused by varying proportions of salt.

In sand germination is reduced much more than in loam, and the effect of salt is greater generally than in loam, and in a dry climate than in a wet climate.

Summary of his results.—Land containing more than about the following percentages of soluble salt are probably not suited without reclamation to produce ordinary crops:—

In loam—.3 per cent. chlorides.

In coarse sand—.2 per cent. of chlorides.

Per centages of common salt in coarse sand giving about half normal germination and production of dry matter in wheat—.2 per cent.

(I).—Paper on "Effect on plant growth of sodium salts in the soil" by Headley, Curtis, and Scofield of the United States Department of Agri