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  CLIMATIC features have a profound influence on soil development. Gently failing rains are better for natural absorption-fertility than sudden heavy downpours. The gentle rains are absorbed into the ground with all their fertility factors. Ground moisture lasts longer and beneficent decay continues while moisture is present. The surplus water percolates underground after the majority of fertility factors are filtered from the rainfall. All the gases contained in the rain become available in sufficient or maximum quantities to aid optimum fertility development. Many kinds of basic minerals, organic elements and chemicals are contained in the air.

  There is every reason to assume that a wide variety of elements are brought into the soil when rain is absorbed and held long enough to enable the humus of the soil to filter these into itself.

  In the harsher climatic conditions generally affecting most of the Australian farming lands, natural absorption fertility does not operate to the extent it does in countries of milder climatic conditions. Moisture losses continuously retard decay. Methods of extraction fertility farming act more rapidly to reduce soil fertility to the stage of active soil erosion. Australia, of course, is not alone in this. America and Africa have similar conditions. The causes of erosion are precisely the same in these and many other countries.

  Just as obviously absorption-fertility farming on these lands will be more strikingly effective than in the countries of benevolent climatic conditions. If, by every practical means, rainfall is absorbed into the earth and all its fertility elements held, and if evaporation losses of moisture are retarded greatly and processes of decay continue longer, then these countries of the harsher climates may develop more rapidly in fertility than the others. In such development, the most important type of country of all is unquestionably the steeper mountain and hill lands.

  The effective control and rapid soil developments of these lands will do much to mitigate the calamitous effects of the worst feature of our climate,. The worst effect of droughts and flood can be fought and conquered by absorption-fertility methods of farming and grazing if applied quickly to these steeper lands.

  At the present time the rapid run off from these lands directly causes uncontrollable and destructive floods, with losses of life, alarming destruction to property and stock, and the choking of rivers and harbours with silt. The trail of havoc extends from the mountains to the sea.

  In dry, hot weather the steep undeveloped and uncontrolled lands are a constant menace with their bushfire hazard. Extermination of rabbits and other pests is more difficult in these lands.

  Present recommended orthodox practice is to fence well, stock conservatively and leave the timber on these steep lands in order to protect them from erosion.

  The trees of the steep grazing lands of Australia do not of themselves prevent erosion. Only good management does that. Timbered areas require better management to protect them than do grasslands.

  Generally, the present condition of this steeper country is such that it will not grow both good grass and good timber.

  A Keyline principle is that planning and development above the Keyline comes first. This development must be sufficient at least to protect the lower lands.

  The full development of steep country can only be accomplished rapidly and effectively if it can be made to pay. The profit must be almost immediate and definite--not something in the dim and distant future.

  The first approach is simply to enable the steep country to absorb the rain that falls on it and keep it in this condition. Then follow the Keyline method of soil improvement for pasture lands.

  The clearing of this country on the Keyline clearing plan leaves permanent timber strips that form a guide for Keyline Absorption-fertility cultivation.

  The full control that this gives will enable the effective control of bush fires. The parts of this steep country that may be adjacent to an outside fire risk area can be managed to protect the whole property. It can be heavily grazed or cultivated to form a completely effective fire break.

  Considerable acreages of this steep country, often regarded as of lesser or almost insignificant value, will be found to develop better pastures than the land now considered as the best on the farm.

  At present, when a farmer leaves his steep country in timber it is usually because he feels he must do so. Sometimes it is left because he really wants to run it as a forest for profit or for general farm purposes. He thinks then that the steep country is the only place for such a forest. In the Keyline development of steep country the farmer has the choice. He can develop high quality soil and pasture, or if he wants a forest area he can have this in the steep country or anywhere else.

  Australia is, geologically, a very old continent. There are no very high mountains and practically no steep country of long, unbroken slope. By steep slope country is meant slopes of 100 per cent., or a rise or fall of one foot for each horizontal foot. Many slopes of 100 per cent. do exist, but they are nearly all short slopes rarely 150 feet long horizontally. These short steep slopes generally exist as the sudden dip-overs that form the valley heads--the start of the valleys. If the farmer wants some good growing timber he will rarely grow it on this short steep country. Much better timber will grow on the flatter country above and below.

  The clearing of timber on sloping country is dealt with in "Keyline Timber Clearing". Slopes of up to one foot rise in three feet are Keyline developed as described in earlier chapters. Most wheeled tractors will do this safely and well. The three-point hitch and other tractors on which implements are mounted, especially those of about 30 horse power, are particularly effective.

  For short slopes steeper than one in three and up to one in one, a rawler tractor and a trailed Graham will provide means for full development of soil for pasture growth.

  Keyline cultivation of the type required, up to three workings, is first completed above the slope to 30 feet from the steep dip over. The slope is then plowed directly down hill. The tractor and "plow" make the turn in the flatter area below and then travel squarely up the steep slope in the same width of plowing of the downhill work. Turn in the flatter area above and plow directly downhill beside the plowed ground of the first downhill plowing width. Continue plowing directly down hill in new ground and uphill in the plowed land of the previous downhill width. By "breaking ground" only on the downhill work and travelling uphill In the plowed ground, the load on the tractor of the uphill work is reduced to such an extent that the tractor will handle the implement on the uphill travel without continuous implement depth adjustment. The whole of the steeper country receives two cultivations by this means, and this completes the steep country plowing.

  The next step is to start from the Keyline and plow the area above the Keyline to the bottom of the steep country plowed area. Follow Keyline cultivation parallel to the Keyline on the last run.

  This land may in a short time grow some of the best pasture on the farm.

  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 display significant improvement by Keyline full development undertaken in the area immediately above it. It will probably be much richer in the minerals of fertility than land that has been heavily cropped and grazed by methods that have not only been extracting fertility but destroying more fertility than they extract in crop and stock production.

  Our droughts and flooding rains are factors of prime importance in the loss of fertility and later in soil losses by erosion.

  The effects of both are capable of profit producing control, by the absorption of fertility into the soil of the hill lands.

  Valleys start or head where a portion of a slope near the top of a watershed or divide becomes steeper than the general slope on either side. Thus the first part of a valley formation is steeper than the ridges or shoulders on each side that form the valley. At some point down the valley--the Keypoint--the valley slope flattens to such an extent that it becomes flatter than the ridges or shoulders on each side in the same vertical interval.

  These factors, as already stated, locate our Keylines. The valley itself and the ridges that form the valley are the two points that require special care once the steeper land above has been controlled by Keyline Absorption-fertility. The valley floor has been a danger point for erosion and may have gullies which require repair. The shoulders of the valley are usually the driest areas.

  While the valleys of the usual farming and grazing property, if not eroded, carry more moisture than other areas, they continue to extract ridge moisture even when the valleys are too wet for healthy growth. This "dog in the manger" aspect of the valleys is quickly offset by Keyline cultivation. The ridge areas then receive and retain their fair share of moisture for longer and longer periods.

  If the valley is eroded the erosion holes will continue to bleed moisture to the atmosphere until little remains. The effect of this process can be observed where every tree of a forest is dying in an eroded valley area.

  Sufficient has been said in earlier chapters to illustrate the effectiveness of Keyline cultivation in the control and development of absorption fertility in valleys. Where significant gully erosion exists this can also be controlled by correct Keyline methods.

  Keyline development first controls the usual water run off into valleys from the higher land, by tremendously increasing the absorption capacity of this area and diffusing the excess water, thus greatly retarding and delaying its concentration time.

  With the high country in this condition effective gully control and repair in the valley below is simplified. If the hole or gully is not large, repair is best done without the use of bulldozers. Repairs with these implements, where the valley soil is not deep, too often result in the topsoil finishing in the hole and a relatively large area of slow-to-improve subsoil remains. This will spoil the look and value of the repaired valley.

  A much better procedure is to use the Graham Plow for the repair work.

  Plow up each side of the valley, allowing one end of the "plow" to drop over into the hole. Spikes with heel sweeps quickly move sufficient soil and subsoil from the banks into the hole and allow the "plow" to cross in all directions. Only sufficient filling or levelling of the hole is necessary to ensure that the deeper part of the hole is not lower than the valley immediately below. In this way ponding is prevented.

  This repaired valley does not then expose all subsoil. The soil and subsoil will be mixed and the effect of a bare infertile patch in the valley will more quickly disappear.

  Immediately the repair is complete the area is Keyline cultivated or pasture improved and the repaired area is practically safe.

  It is seen that the procedure is as follows--assuming the holes are below the Keyline. First complete the cultivation above the Keyline. Second, plow in the holes. Third, immediately Keyline cultivate the area from the Keyline paralleling the Keyline downward.

  If the area treated is poor heavy soil, very low in humus content, it will tend to seal quickly from very heavy rains. When this happens the area is treated again both above and below the Keyline on the procedure already discussed for soil improvement of pasture lands. This is necessary to provide oxygen so that improvement will continue. Without oxygen both decay and growth will tend to cease. As the soil improves less cultivation will be necessary to provide aeration and absorption. The improved soil will provide these itself.

  The great advantage of Keyline aeration cultivation on soil that is sealed is sufficient to warrant its use even if a recently sown pasture is still new and weak. In these circumstances the cultivation still follows the Keyline procedure. Spikes are to be used and spaced 24 inches apart. One fast run completes the necessary Keyline aeration cultivation and soil improvement will continue without check.

  If the erosion holes and gullies in a valley to be Keyline improved are merely to be "killed" or prevented from getting worse, the procedure is the same except that the Keyline cultivation--that is the final cultivation run--is divided or split to suit these circumstances. See Map 5.

  Parallel the Keyline progressively crossing and re-crossing the valley until the first erosion gully is encountered. Then complete the parallel runs downward, working to the gully and back on one side until this side cultivation reaches the end of the hole. Continue the cultivation on the other side of the hole to the bottom--downstream end--of the hole. The next cultivation run will then be a complete one parallel to the others and again crossing the valley but now below the hole.

  All this cultivation running from the erosion hole out and away from it will have the Keyline drift away from the hole. Only with very heavy rain will water again run in the gully, and if any further erosion takes place it will be on a greatly reduced scale. With continued Keyline soil improvement it will cease altogether.

  In times of severe drought the only noticeable green tinge on a grazing property will often be the narrow moist strip in a valley. One of the first very noticeable effects of Keyline development if followed by severe drought conditions is the greatly widened area of longer-lasting valley greenness.

  Keyline soon multiplies the effects of the average rainfall.

  Practically no valleys are safe from erosion under "extraction-fertility" methods of farming and grazing, while under methods of Keyline Absorption-fertility all valleys, including those of the steeper land, are safe from soil losses and consequently erosion. Not only are they safe, which is a negative matter, but they will improve progressively with all other land in fertility, productiveness and beauty.

  The use of trees in Keyline planning is discussed elsewhere in this book, but a special reference to trees and their effect on valleys can be considered here.

  In the Keyline development of land, trees are not generally left in valleys except as part of a Keyline or Guideline timber strip. The eddying of water caused by a tree in the path of the water flowing down a valley will often commence an erosion gully. The breaking of the soil round a tree from root movement and growth can also be a contributing factor.

  Stock sheltering beneath a tree tends to powder the soil around it, thus causing soil movement when water flows down the valley.

  The effect of both these erosion hazards will be quickly offset by Keyline improvement. It is still advisable to clear the valley timber except when a Keyline or Guideline timber strip crosses the valley. Stock will not damage this timber which is left in a valley as part of a timber strip crossIng the valley.

  The Keyline development of valleys is simpler and more rapidly effective if there are no odd trees to consider.

  It has been noted that a mob of cattle in a large paddock containing three timber strips at different levels invariably all camp in the one timber strip and spread themselves well along the line of this belt. A night or two later they will be together maybe in a higher or lower timber strip.