SCHEME OF SOIL CONSERVATION

Press, Volume XCIII, Issue 27896, 18 February 1956, Page 7

SCHEME OF SOIL CONSERVATION

WORK OF AUSTRALIAN ENGINEER STUDY OF “KEYLINE” PLAN In the field of soil plus moisture conservation and development m hul country the ••Keyline" plan is regarded as a notable advance in many reliable quarters in Australia. The system, which might well have an application in New Zealand also, was studied by Mr Murray Craighead, a member or the staff of “The Press," when he visited Australia recently under the Robert Bell Memorial Prize fol journalism, which he won at Canterbury University College. “It was not until 1 saw Keyline and all that it means—the simplicity and economy with which its manifold objects are achieved—that I really ten that here was a system of soil and pasture improvement which seemed to answer all the questions,” said Mr Harold Sarina talking to Mr Craighead of his impressions of “Nevallan, about 50 miles from Sydney, where Mi P. A. Yeomans devised and developed his “Keyline” system of farming. Formerjy secretary to the Royal Agricultural Society (New South Wales), Mr Sarina broke a long association with the society to become secretary of the Keyline (Research) Foundation, of which Professor J. R A. McMillan, of the agricultural faculty of Sydney University, is a trustee member. It is scarcely three years since Mr Yeomans conceived his “Keyline plan as he looked up the heads of the steep valleys just below his homestead at “Nevallan.” Since that day the change has been remarkable. Erosion has been overcome by a naturally increasing soil fertility. Stony gullies have gradually filled with ncn loam as “keylining” progressed, and grasses have crept across rocky ground and down and over watercourses slowly covering the scars. The soil has gradually changed in colour—in one area from a whitish colour, till today it is a rich dark brown. This is the result of what Mr Yeomans describes as “fertility absorption.” More traditional methods of cultivation and cropping he regards as “fertility extraction,” where the farmer has each year to replace the goodness taken out of the soil. A Sydney mining engineer. Mr Yoemans has devoted many years to studying land problems and applying his engineering knowledge to his farming practice. Usually a true contour, the “keyline” extends from a point in the valley floor termed the “keypoint” in both directions from the valley to the

adjacent ridges. The “keypoint” is the point where the valley slope in the same vertical plane becomes less steep than the ridges or shoulders on each side. The pegging of the “keyline” is the only survey work involved. Chisel Plough The first aim of the “Keyline” is to establish a simple means of conserving all the rain that falls on the land, retarding its evaporation and using this conserved moisture for rapid development of soil fertility. This is achieved . by ploughing parallel to the keyline using one of the comparatively new ’ chisel plough cultivators with tines one to two feet apart depending on the ' nature of the country and the initial depth of cultivation.

First the cultivator is used on the area above the “keyline” working away from the line, and then it works down from the line. As the chiselled furrows move away from the “keyline” they gradually become off contour, with the result that the furrows have a slight downwards slope from the valleys to the ridges. The area virtually becomes hundreds of thousands of small drains. Water no longer runs off the ridges to rush down the valley. Rain is effectively trappeo underground and distributed over a maximum area. Greater water absorption and soil aeration made possible by the chisel plough, which can be set to a maximum depth of It. inches, starts a cycle of increasing fertility. Plants grow better with the improved soil moisture content and the superior plant growth means more organic matter and an improving physical condition of the soil.

For areas where there is no “keyline” Mr Yeomans recommends the establishment of a “guide line” on which work can be based. This can be used where a paddock has a slope m one general direction. conservation and development is promoted by the chisel furrows drifting away from the natural run-off direction.

Trees also have a part in Mr Yeomans’s plan. He leaves or establishes a strip of trees just below and parallel to his “keyline” which forms a permanent keyline timber strip. In both directions from the “keyline” timber strips have been preserved or planted on ‘‘Nevallan” on the contour at regular intervals. The vertical spacing of the strips is related to the height of the trees. If the trees are 45 feet high the strips may be 40 feet apart vertically. This provides some overall wind protection. Damming Recommended Compaction of the soil, which Mr Yeomans says is one of the greatest destroyers of fertility, is reduced to a low level as the comfortable conditions in the timber strips keep cattle off the wet soft ground to a large extent. Whereever practicable, Mr Yeomans recommends the construction of dams on the “keyline” in the valley and the keyline itself constructed as a gently falling drain to carry water. Other dams may be established both above and below the “keyline” dams. Four-inch pipes are let into the dam walls and where there is a vertical drop of 50 feet or more to land below spray irrigation may be carried out. The western area of Mr Yeomans’s farm was developed by “keyline” methods only. The work occupied little time and involved only about one-tenth of the work done at the other end of the farm. Mr Yeomans has written: “Unless it is solid rock there is probably no country too steep for improvement if stock will climb it for food. Country that carries some soil, even if it is very steep, will show significant improvement if full keyline development is undertaken in the area above it.’”

Mr Yeomans has shown that under his methods the soil can retain several more inches of rain before there is sign of run-off and the plant growth that follows the application of the “keyline” methods are deeper rooting and more vigorous important factors in resisting erosion.

OVERPRODUCTION PENALISED

A Tioga farmer in the United States has been directed to pay a penalty of 314.72 dollars for overgrowing his wheat quota in 1954. The Government said Frank E. Bean, or Nichols, New York, had grown 22 acres of wheat while his acreage allotment for the year was 12 acres. The action was brought under the Agricultural Adjustment Act of 1938, which governs wheat planting.