Soils, analysis of, etc — About 200 samples of soils taken from the surface from 6in. to 18in. and from 18in. to 36in. deep were examined for salt by the Government Analyst (Mr Mann). The tables of the analysis cover five sheets of figures, which, if attached to this report, would serve only to confuse readers, and probably leave a wrong impression. I will, therefore, endeavour to summarise the results of the analysis and make clear the position. A complete analysis of samples 1 to 30 was made and the results briefly put are: Not rich in humus, well supplied with lime, well supplied with potash, weak in nitrogen and phosphoric acid, as are most of the Western Australian soils. Proper farming and manures will make good the above. In these samples salt was found, so it was decided to test all other samples (170) for salt only. Here are a few remarks about salts in soils will help readers to understand what is to follow concerning the particular soils in question. I make no apology for the length of these explanations, because the subject is very important and great issues are at stake. Tolerance of Alkali Salts by Plants — By alkali salts in agriculture three substances are most commonly understood. These are common salt (sodium chloride), Glauber salt (sodium sulphate), and carbonate of soda (sodium carbonate). The latter is commonly known as in America as salsoda and, when in the soil, black alkali. In addition, magnesium chloride, magnesium sulphate, calcium chloride, and others are included as soil alkali. In addition, magnesium chloride, magnesium sulphate, calcium chloride, and others are included as soil alkali salts, but the subject is sufficiently complicated if we confine ourselves to the three first mentioned. Everyone knows that an excess of the above salts in a soil is injurious to plants, and if the percentage exceeds certain limits the plants are destroyed. One is often asked how much salt may a soil contain and yet grow good crops. This question is by no means as simple as it looks, because it usually happens that the three salts under consideration are found in association possibly with others. The proportions of each will vary so much that it is probably impossible to decide to what extent each one is responsible for injury. The farmer knows that soils are derived from the decomposition of rocks, and anything which the soils contain, apart from the organic matter, must be found in the rocks from which they are derived, although usually in very different chemical forms. The granite and diorite rocks from which the soils in the agricultural areas are chiefly derived, contain among other things certain compounds of sodium, calcium, magnesium, and potassium. From these original, insoluble chemical compounds soluble ones formed during the process of decomposition of the rocks. Some of these are good for plants, while others are injurious if in excess of certain limits. Some are much more soluble in water than others. If there is a heavy rainfall, the rain washes out the soluble salts as they are formed, so that we do not have the same accumulation in wet districts as we do in country with a limited rainfall. If we take any area of land in the eastern Districts, say near Beverley, or York, or Northam, we find the country in its natural state covered with forest or scrub growth, which largely absorbs the limited amount of rain which falls, and salty patches are rare and confined to special hollows receiving drainage, or surface water. This is because the soluble salts are more or less evenly distributed throughout the soils, on the hillsides through the whole extent of the country. When the land is ring-barked, cleared and broken up, natural vegetation no longer utilises the larger proportions of the rainfall, which entering the ground dissolves more or less of the salts, and as it soaks through the soil and gradually flows down the hillsides to the lower land, and the water carries the salts with it. In the summer time heavy evaporation takes place from the lower lands, the salt being left behind. After a few years this naturally results in large increase of salts in the hollows, and they are known as salt pans, samphire flats, or salt lakes. The problem of dealing with the salt in agricultural lands is much more difficult than explaining how salt pans originate, and requires careful, thorough, and patient investigation. Certain crops are able to withstand a very much higher percentage of alkali salts than others, and many plants, if they are once able to get a firm hold, will thrive very well under conditions where the tender seedling will not grow. the safe limit of salt percentage which permits of profitable agriculture, very largely depends upon special conditions and the farmer will be on much safer ground in experimenting for himself than in seeking advice from the agricultural expert or chemist. Very little local knowledge is available, but the alkali problem is so important in some of the Western States of America that a great deal of investigation has been carried out, especially in connection with irrigation. Now, returning to the study of the samples of soil examined by Mr. Mann: in his report Mr. Mann writes:— I have throughout adopted the standard of .05 per cent. of salt as being in my opinion a reasonable one, although there is a considerable amount of variation amongst authorities on this subject; the limit of endurance for crops being stated as from .03 to .5 per cent. It must be noted that Mr. Mann is not dogmatic re the standard he has adopted, and he admits freely that authorities differ. After searching for local knowledge I find very little is available on this subject. Some experiments have been made with artisan bore water in New South Wales with relation to plant life, but the results are so involved, there being other minerals besides salt in the water, that the knowledge gained is no use in this report. Professor Hilgard of California is a recognised authority on the subject. Hilgard on Soils (1910), p. 464 — Relative injudiciousness of the several (alkali) salts:— For the sandy loam of the Tulare substation, California, for instance, the maximum for cereals may be approximately stated to be — .1 per cent. sal. soda (sod. carb), .25 per cent. for common salt, and from .45 per cent. to .50 per cent. Glauber salts (sod. sulp.). Bailey's Cyclopedia of American Agriculture, Vol. 1, p. 521:— When the bulk of the alkali is sodium chloride, or sodium sulphate, 0.4 per cent., of total salts in the first six feet seems to be about the limit for a good growth of wheat. The ....or macaroni wheats are considered more resistant than soft wheats. In Utah oats gave a fair stand when the alkali (mostly common salt) amount to .04 per cent. in the first three feet of soil, while they failed in 0.7 per cent. chiefly held in the second foot. T.H. Kearney, Physiologist, and Frank Cameron, Soil Chemist, in Bulletin No. 71, Dept. of Agriculture, US., p. 20, gives:— Limit of endurance for wheat — 1.8 per cent. Limit of endurance for peas — 1.2 per cent. Limit of endurance for white lupine — 1.2 per cent. Limit of endurance for maize — 1.4 per cent. It will be noted here that there is a wide difference between the standard adopted by the Government Analyst and other authorities quoted. Now to compare the percentage of salt found in our soil samples with the authorities above. See Table 1 hereunder. The average percentage of Sod. Chloride, Table 1 (cultivated land)— Top 6 inches — 6 — 18 inches — 18 — 36 inches .086 per cent. — .230 per cent. — .270 per cent. with a wide range between individual samples. These samples were collected in July, when a considerable proportion of season's rain had fallen. It is apparent that some of the salt in the surface must have been washed by rain into the subsoils before these samples were taken.