THE RURAL WORLD

Otago Daily Times, Issue 23705, 12 January 1939, Page 3

THE RURAL WORLD

FARM AND STATION NEWS

By RUSTICUS.

ftami .of interest to thoso engaged in agricultural- and pastoral pursuits, with a view to their publication in these columns, will be welcomed. They should bo addressed to Rusticus, Otago Daily Times, Dunedin.

1938-39 WOOL SEASON ROSTER OF SALE DATES The following roster of sale aate& for the 1938-39 seasor has been drawu up by the New Zealand Wool Committee:— January 14 (9 a.m.).—Napier January 19 (9 a.m.).—Wanganui January 24 (9 a.m.).—AucklandJanuary 30 (9 a.m.).—Christchurch February 3 (2 p.m.).—lnvercargilL February 8 (9 ajn.).—Dunedin. February IS (9 a.m.).—Wellington February 20 (9 ajn.).—Napier February 24 (2.30 p.m.),-wangai.ui March 3 (9 a.m.).—Christchurch March 7 (8 ajati.).—Timaru March 11 (2 p.m.).—lnvercargill March 18 (9 a.m.).—Dunedin. March 23 (9 a.m.).—Wellington March 27 (9 a.m.).—Auckland. March 30 (2.30 p.m.) -Wanganui April 3 (9 a.n.).—Napier April 14 (9 a.m.) —Christchurch. April 19 (9 a.m.).—Dunedin. April 24 (9 a.m.) - Wellington. 1938-39 SHOW SEASON . V ROSTER OF DATES Summer shows have been arranged t>r the 1938-39 season as follows: December 27.—Tuapeka. at Lawrence 1939. January 14.—Waitati. January 21.—Waikouaiti. January 27.—Palmerston-Waihemo. at Palmers lon. March 4.—Central Otago, at Onakau March 11.—Mount Benger. at Miller's Flat. March 18.—Upper Clutha., at Pembroke. March 18.—Temuka and Geraldine. at

Winchester. March 22.—Lake County, at Lake April at Middlemarch. April 10.—Mackenzie Highland, ai Fairlie.

USE OF FERTILISERS FIRST WORLD CONGRESS WIDE DIVERGENCE OF OPINION The first World's Congress, held in Rome from October 3 to 6, under the auspices of the International Federation of Technical Agriculturists, was attended by delegates representative of no fewer than 48 different countries. President of the congress was his Excellency the Baron Giacomo Acerbo of Italy, and vice-presidents were elected from France, Jugoslavia, Great Britain, United States of America, Belgium, and The Netherlands. Being the first congress of its kind, it was inevitable that much of the discussion was exploratory, having as its object research into the question of how best the agricultural producers of the world could be served by the producers and distributors of fertilisers. Most of the reports received and presented, for the same reason, were factual rather than constructive, and described existing conditions in the reporting countries. From this particular viewpoint the congress was an outstanding success, and subsequent meetings which, it was resolved should take place every three years, should show results of great practical value. The work of the congress was divided into four sections dealing respectively,with the following aspects of the problem:— XI) Raw materials and the production of fertilisers; (2) the technique of fertilisation; (3) the economics of fertilisers; (4) education and propaganda. The organisation of the conference has been proceeding for the last 18 months, and numerous national reports had been submitted. MIXED FERTILISERS' The general communications, general reports, and national reports which have just been received in Australia indicate the great scope of the work. Of particular interest were the statistical tables indicating the great differences in technique from country to country. These differences concern the total quantities of fertiliser applied per acre, the types and quantities of fertilisers used, and the trend of fertiliser practice in relation to the use of mixed fertilisers. Belgium, one of the most advanced of all countries in the use of fertilisers, of its total of over one million tons of fertiliser per dnnum, uses but 5.4 per cent, in the form of compound fertilisers. At the other end of the scale lies Greece, where 77 per cent, of the total is applied in mixtures. The United States, among the greatest of all countries in total consumption, with a 1937 total of nearly 7J million tons, applied 67 per cent, in the form of mixtures. Germany is probably the greatest single consumer of fertilisers, with a total of over eight million tons, and of this 22 per cent, is .used in the mixed form. • Surveying the world as a whole, a marked trend is noted in the types of fertiliser used. The situation is best expressed by figures from the United States. In 1925 the average of all the complete fertilisers sold in that country had a composition of 2.6 per cent, nitrogen, 9.3 per cent, phosphoric acid, and 4.1 per cent, potash. In 1936 the average bercentage composition was 3.7, 9.3, 5.5. It is to noted that the increases in the percentages of nitrogen and potash have not been obtained at the cost of the phosphoric acid, but rather by the use of more concentrated constituents. Germany shows the tendency toward greater concentration in an even more marked degree; for most annual crops, spring sown, a 7,7, 14 mixture is used. For autumn sown cereals, 3, 10, 15 is the favoured formula. For horticultural use a mixture of the formula 16, 16, 20 is favoured. . . An equal divergence of opinion exists on the question of the quantity of fertiliser per acre. Belgium again ranks high in this regard, and the official recommendations for the main crops range from 500 to 800 pounds per acre for various cereals and for pastures, from 1000 to 1800 pounds for potatoes and field vegetables, and from 1000 to 1200 pounds for orchards. An unexpected variety of opinions came in reply to the question of the relative advantages of mixed fertilisers versus single ingredients. The general opinion from the -countries of more scientific agriculture favoured the single ingredient system, while from the more extensive countries the mixture received more support. The best summary of the question came from Spain, which said. "The commercial compound fertiliser is an advantage for the less enlightened farmer, but something of a hindrance for the more enlightened farmer, who should compound and apply his fertilisers in a rational manner." Germany expressed the opinion that the mixed fertiliser was more valuable in special cases where the exact soil conditions and crop requirements are known. Among items of more general interest noted from the various countries were the regulation which enacted that the content of any one ingredient in a complete fertiliser should not be below 5 per cent, and the law limiting the profit permissible on the sale of fertilisers to 12 per cent. In the latter instance the report does not make clear whether gross or net profit is indicated! Some countries seem to foreshadow legislation compelling the use of adequate amounts of correct fertilisers; the production of maximum quantities of food with the minimum of detriment to the soil is, when rationally considered, a matter of some considerable national importance.

EROSION OF FARM LANDS STUDIES IN CAUSES TWO PRINCIPAL FACTORS With the realisation that the end of our virgin land is now definitely in sight, we in New Zealand are becoming more interested in the problems of land deterioration and soil conservation, writes Mr N. H. Taylor, of the Soil Survey Division, Whangarei. Among other questions we seek to learn what part soil erosion plays in the deterioration of some of our farm lands. Two chief types of erosion are sheet and slip erosion. Sheet erosion is the removal of a thin, more or less uniform, covering of soil during rains producing run-off. To the casual observer there is nothing very spectacular to be seen —just a general impression of deterioration. Soil with a close cover of pasture grasses is effectively protected from this type of erosion, but where it is bared, e.g., after a forest or scrub burn, or when the pasture is open, allowing of much bare ground, this type of erosion attacks the uppermost and most fertile layers of the soil. The practice of continued burning of second growth and roughage is one of the chief causes of deterioration by sheet erosion.

There is another aspect to be considered. Unless the grass cover is kept continuously the process of forming a grass soil is delayed and there is no steady progress toward the desired permanence. To alternate scrub and fern growth with grass upon a hillside is somewhat akin to rotating crops. The turf cover is weak and parts of the grass humus already built up are eroded away when exposed after a burn.

EROSION BY SLIPS Slip erosion is the moving down the slope of large blocks of soil. The top soil may slide over the subsoil or both the top soil and subsoil may slide from off the weathered rock material below, or else all these horizons may together slide from off the undecomposed rock. On the clay hills of North Auckland slipping appears to be of two kinds. There is a shallow slipping which appears to be the accelerated form of the normal soil creep that takes place under forest. The soil, weakened by the cracking and swelling in wet and dry periods, and being no longer supported by the roots of forest trees, tends to move downhill at a greater rate. During dry summers rain water flows down the cracks until it reaches an impervious horizon, when it percolates downhill, sometimes reappearing at the surface lower down the slope. Water entering in this way lubricates the subsoil above impervious horizons and induces slipping. In some places the hillsides are covered with shallow slips induced this way. Where there is a strong and complete grass turf more rain water is absorbed and the ground does not crack so readily, but where the grass humus layers have either not been built-up or have been removed by sheet erosion the ground cracks badly and shallow slipping quickly takes place. RESULT OF FOREST FELLING

The larger slips, however, do not appear to bear much relation to the type of grass cover. As already stated, they are the accelerated phase of the slipping process normally taking place under the forest cover. Following the destruction of the forest, the weathered rock mantle is weakened by the greater moisture fluctuations. Hence these slips appear at their worst some years after the forest has been felled, and especially when an exceptionally wet season follows an exceptionally dry one. They nearly all move forward on impervious horizons over which ground water is seeping. At the back they leave steep, arcuate scars on which are exposed the underlying decomposing rock, and it is this back portion of the slip that is most difficult to grass. The slipped portion moves forward and downward to form the toe of the slip. On, some slips the grass covering of the toe is preserved largely intact, but in many places the excessive run-off from the bare ground at the back of the. slip quickly cuts the toe into channels.