Climate--The First Factor
CLIMATE, the first factor on the Keyline scale of permanence,governs our approach and guides all agricultural matters. Climate sets the patternof farming and grazing. The traditionally independent man on the land is completelydependent on the weather.
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For the sake of clarity and brevity in the following discussionsit will be assumed that we are dealing with the fairly general type of poor agriculturalclimate so typical of Australia's farm and grazing lands of the mid-temperate zone.This area is not snowbound for months in each year, but the temperatures are oftenhigh. The rainfall is insufficient and unreliable and droughts of a few months occurevery year; flooding, destructive rains occur about as often as the severe longerdrought. The position of excessive run-off followed by rain shortage for pastureand crops is a more or less constant feature. Generally, if all the water that runsto waste was conserved it could be utilised in practically every year.
Life cannot get down to living, let alone developing fully,until it is adjusted satisfactorily to its environment. This is the climate thatset the course which our agriculture is only now seeking to follow.
The natural soil of this climate would not generally be of thedeep, highly fertile type. Its development would have been continuously retardedor restricted by the shorter period of good soil climate and the longer and morefrequent dry soil periods. It would have reached a natural development of a low tomedium fertility and would not now be improving, Its fertility is constantly ebbingand rising a little, according to the season's changing climate.
Our climate cannot be altered, but as soil climate is the criticalfactor, what can be done to improve the effect of our general climate on soil climate?Varying degrees of beneficial control may be exercised on moisture, warmth and air.
First, water must be used more effectively and none must beallowed to run to waste.
If the period in which adequate or improved amounts of moistureremain in the soil is extended, even a little, the improved soil climate quicklyaffects the whole of soil-life development and with it the fertility of the soil.
Planning, then, is designed to retard moisture loss in hot weatherafter more moisture from rain has been induced to enter the soil's depth. All run-offrain, conserved in farm storages, is to be made available as irrigation water andapplied to the special irrigation areas immediately it can be used. It may be neededas early as six or eight days after rain in summer and surely must represent a verypowerful instance where soil climate can be tremendously improved. Air, too, is tobe kept in the best association with moisture and warmth.
The correct association of these three influences--moisture,warmth and air--provides the best conditions for pasture and crop growth, and alsothe optimum conditions for the development of soil-life climaxes which rapidly changethe whole soil, its colour, structure, feel and smell.
Since roots are dying and new ones are developing continuouslywhile there is growth above ground, lack of air to the full depth of this dead rootzone restricts and wastes the benefit in fertility to the soil of this importantorganic soil food. Therefore, air is to be provided to the full depth of this zonewhen the other factors are suitably present. It can be done by the right type ofcultivation at the correct timing for soil life and at the appropriate depth. Allitems are to suit the particular soil and the condition of the soil at the time ofcultivation.
Climate--the first factor on the Keyline scale of the relativepermanence of things agricultural--sets the approach to everything.
Adequate air is provided by means other than cultivation ina soil that has been developed to a high state of fertility. The teeming soil-lifepopulations provide air by the strong and continuous formation of the crumb structureof this soil and the burrows of the soil life itself, the dominating and obviousones being the larger forms, the earthworms. The large roots which on dying and beingabsorbed into soil leave channels in the soil. Good aeration, a constant factor offertile soil, waits for moisture and warmth. The earthworm population, large andvigorous, continuously moves in the section or horizon of the soil, where for thetime being it finds the most suitable living conditions. When these influences extendto the surface of the soil, the earthworms will break through and cast all over theland. They delve deep into the subsoil, casting as they go into underground passagesand cavities. The effect on the factor of aeration by an immense earthworm populationin a highly fertile soil must surely approach perfection.
When the soil we are developing, by first of all improving theeffect of general climate on soil climate, approaches this state of high fertility,it can look after itself. It will provide its own air requirements, absorbing itsfull share of rain and continuing to improve. When it does eventually lose its moistureand dries out, which it does more rarely as it improves, its response to small amountsof rain is dramatic. On the other hand, on such a soil, a week of flooding rain willcause no damage. It holds its air and does not drown nor asphyxiate.
When irrigation water is applied to land it critically affectsthe soil. Poor natural soil developed in poor climate cannot withstand this new condition.Water is an essential part of the soil fertility process, but it can, and does, drownand destroy as well as develop and preserve soil fertility. Whenever irrigation wateris applied to soil, then that soil needs air. It may need to be provided more drasticallyfor a time than in any other circumstances of the soil's water and air relationship.The great improvement in soil climate which increased quantities of water make possiblecan only become real, valuable and permanent when air also is suitably present.
Only soils of the highest fertility other than coarse dead sandsare capable of maintaining a suitable relationship of moisture and air when greatlyincreased quantities of water are applied. When this optimum relationship is maintained,then the poor soil under irrigation will be transformed into highly fertile soilin an incredibly short time. A summer season of the new soil climate that irrigationwith adequate air can maintain will produce a complete transformation of poor clayeysoil. This has been a consistent result on our "Nevallan" and "Yobarnie"properties each time we have applied irrigation water and maintained, with adequatecultivation, good soil aeration.
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There is an almost infinite range in types of climate. Thereis great variety even in the general climatic condition that forms the backgroundto these discussions. There is every type and variety relating to the one factorof precipitation--rain, snow, ice, dews and fogs. Then there is the wide varietyof other climatic effects on the general pattern of precipitation, such as prevailingwinds, seasonal winds and heat and cold.
A dominantly winter, but low annual rainfall area may stilllose great quantities of water by run-off in the winter. Although generally a dryclimate, the over-abundance of rain in the winter may be the most unpleasant andunmanageable aspect of the farming enterprise. An annual rainfall of 18 inches inthis case would provide very significant run-off for valuable farm storages. Anotherclimatic condition with the same rainfall but spread uniformly throughout the yearmay not provide any regular water for irrigation storages. This climate may produceno reliable annual run-off, but the condition is rare in a Keyline programme, whereoccasional run-off cannot be conserved profitably.
The dominantly summer rainfall region of north-eastern Australiaoften creates a problem of extreme water shortage in conditions where the annualrainfall is 50 and more inches. The greater part of the rain which falls in the threesummer months goes and may leave the property in drought conditions a month later.In these circumstances, large farm storages could be constructed and would provideenough water for extensive irrigation. The impossible-to-grow grasses and cloverswould immediately become highly valuable pasture. A wide variety of plant speciesprohibited by the natural incidence of rain would in the new circumstances quicklybecome part of the economy of the farm.
Cold and heat are powerful agricultural influences. However,the planning of tree belts and water supply can greatly improve the living conditionsof soil life, crops, pastures and stock, where the conditions of heat are uncomfortable.Tree belts also retard the extreme influences of cold. The soil which improves andbecomes darker is notably warmer than a light infertile earth. The darker soil willprovide a better growth factor while at the same time improving and further darkeningto add more warmth to the soil.
Two days of hot drying winds may draw much more moisture fromthe soil than a week of hot weather with no wind. Belts of trees, designed and locatedaccording to a Keyline appreciation of land form and climate, will reduce the windvelocity and the attendant loss of moisture to a very marked degree. The effect oftrees on wind velocity is significant at a quarter of a mile from a good tree belt.
Very severe soil erosion by water is not a characteristic onlyof the medium to heavier rainfall lands. It is often a more dominating feature ofour drier areas, both the flatter western slopes and gentle undulating country. Itis just this type of country that lends itself to the construction of the largestfarm water storages at the cheapest cost per water unit. While today water storageon such country is confined to stock tanks generally, tomorrow this country mustbe dotted with some of our most notable farm irrigation dams. All the advantageousmeans of managing irrigation water, which now apply to our large Government irrigationareas, will then apply in a more economical manner to these large farm irrigationdams.
Water conservation is rarely attempted on such land becausethe orthodox agricultural approach to farm dams for irrigation purposes is that theyshould be designed for real reliability against the minimum annual run-off. justwhy a cheaply constructed large farm irrigation dam is regarded as of no value becauseit only fills once in two, three or more years, I have never been able to determine.
Every single factor of climate can have both a beneficial effect,or a detrimental effect, according to its degree and relationship to the agriculturalenterprise. The frost which wipes out a valuable crop can at the same time have amarkedly beneficial effect on the soil of a recently plowed paddock. Snow, pleasantto play in, but not so pleasant to work in, can have almost a magical effect on soilat times.
The purpose of Keyline technique and the Keyline scale of permanencein relation to climate is to take complete advantage of all weather and climaticphases that will enhance soil climate through maintenance in the soil of improvedrelationships in the factors of moisture, warmth and air, and, by contrast, minimiseto the full the disadvantages of those climatic elements that destroy, namely, floodrains, drought and fire.
In this regard, Keyline climatic technique is the surest formof control of the effects of weather now. in practice.