Here is an essay on ‘Agriculture in Australia’ for class 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Agriculture in Australia’ especially written for school and college students.
Essay Contents:
- Essay on the Introduction to Australian Agriculture
- Essay on Rainfall in Australia
- Essay on Australian Summer
- Essay on Climate in Southern Australia
- Essay on the Soils of Eastern Australia
- Essay on Soil Erosion in Australia
- Essay on Water and Nutrient Management in Australia
- Essay on the Agricultural Zones of Australia
- Essay on Crop Production in Australia
Essay # 1. Introduction to Australian Agriculture:
Agriculture is important to Australia in three main ways:
1. It produces a wide variety of plant and animal products that are used within the country.
2. It supports a large population in country towns that provides services for farmers.
3. Agricultural exports provide Australia with a large part of her national income.
Although agricultural exports are important, they are becoming less so as the export of minerals and other products increases. In the early sixties about 80 per cent of our export income came from selling agricultural products, but in the 1976-77 seasons this had fallen to about 47 per cent of export income.
One way of comparing the importance of different plant and animal industries is to study the export earnings from agriculture.
The animal products have a greater export value than crop products. Wool is still our greatest single earner of export income from agriculture, but its value is growing less.
Looking at the crop exports we see that wheat is our most important single crop. Besides its export value, wheat is also used to produce flour, bread, glucose, gums and other products. It is also the chief food for starving sheep in times of drought. Our exports of other grains are increasing in importance, especially barley, oats and sorghum.
Australian agriculture has undergone many changes in recent years and more changes can be expected in the future. To meet these changes further improvements in agriculture are needed.
Agricultural scientists must help by providing new varieties of plants and finding ways to grow new crops like soybeans, sunflowers and other plants.
There is a need for farmers to become more efficient in their business management and in their methods of production. There is a need for the quality of many farm products to be improved. There is also a need for better education to be provided for farmers so that they are able to become more efficient.
Essay # 2. Rainfall in Australia:
Total annual rainfall varies from less than 127 mm in some parts of Australia to over 4000 mm in other parts. According to the rain which falls, Australia can be divided into humid, sub-humid, semi-arid and arid zones. This map shows that the highest rainfall occurs near the coast, except for the north-west of Western Australia and the shores of the Great Australian Bight, where rainfall is very low.
A farmer or grazier needs to know much more about the rainfall of a district than its total amount. For instance, he is interested in the season when rain falls, how, much rain falls at one time, how reliable the rainfall is and how effective it is.
In general the northern half of Australia receives most of its rainfall in summer, whereas the southern parts of the continent receive most rain in winter. In between these zones of summer and winter rainfall there are areas of uniform rains. For instance, a large part of New South Wales has a fairly even distribution of rain throughout the year.
If we divide the total yearly rainfall by the number of wet days, we determine how much rain falls on an average wet day. In some of the drier parts of southern Australia falls of rain may be as low as 2.5 mm per wet day, but in the high rainfall areas of North Queensland the average fall of rain may be more than 12.7 mm per wet day.
It is the average fall of rain which determines whether there will be enough surface water for streams to form and whether water moving over the soil will cause loss of soil by erosion.
Gentle rain is found more commonly in southern Australia, whereas rain often falls in heavy storms in northern Australia.
It is often important for the landowner to know how reliable his rainfall is and how much he can depend on its falling. It is usually the case that the rainfall is more reliable in one season of the year than another. This knowledge may be important in planning the sowing of crops and pastures, the crutching and jetting of sheep and so on.
The general rules about reliability of rainfall are that rain becomes less reliable as one proceeds into the inland parts of Australia and also as one moves from the areas of winter rains to the summer rainfall areas of the north. Very large areas of central and northern Australia depend on storms to provide feed for grazing animals and here the rainfall is very unreliable and droughts are common.
Knowing the total yearly rainfall for a district does not tell us much about the usefulness of that rain. We need to know whether the rain falls mostly in one season of the year or whether it is spread over the whole year. We also need to know whether the usefulness of rain is reduced because it is evaporated from the soil.
The evaporating power of the air is so high over most of Australia that it can evaporate 2500 mm of exposed water in a year. For this reason 25 mm of rain falling in winter when the evaporating power of the air is less may be more useful than the same quantity of summer rain.
Essay # 3. Australian Summer
:
Australian summer temperatures vary from warm to very hot, the temperature increasing from south to north and from coast to the inland. Summer maxima of 38°C or more are common in inland Australia. During heat waves high temperatures may extend to the coast.
Winter temperatures are warm in the far north, but the average July temperatures in Tasmania, Victoria and most of New South Wales are usually less than 10°C. On the tablelands of Victoria and New South Wales winter temperatures are so low that plant growth almost ceases. Winds may increase the chilling effects of tableland winters.
Winter frosts are common over large areas of southern Australia during the months of June, July and August. On the tablelands frosts may also occur in autumn and spring months, while snow may fall on the higher altitudes.
Seasonal changes in prevailing winds are caused by movements of areas of high or low air pressure.
In winter high pressure systems move in a procession across central Australia. These “highs” travel from west to east, usually taking about five days to cross the continent. Descending air in the high pressure area moves outward in an anti-clockwise direction at ground level.
In summer the processions of high pressure systems moves across the southern parts of Australia while much of northern Australia is under the influence of a belt of low air pressure. The Summer highs bring prevailing easterly winds to much of southern Australia.
Essay # 4. Climates in New South Wales:
The coastal zone is classified as humid, for rain falls in all seasons. The far North Coast has a sub-tropical climate with most rainfall occurring in summer. The most reliable rainfall occurs in autumn, while the winters are sometimes dry.
Rain falls in all seasons on the South Coast, with slightly more falling in autumn. There is no real dry season, but less rain falls in spring. Winter temperatures in all coastal zones are mild.
The tableland areas of the State have a cool, upland climate. Winter temperatures are so low as to prevent rapid plant growth. The Central and Southern Tablelands have rain in all seasons, but winter rainfall is usually heavier than rainfall in other seasons.
On the northern tablelands the heaviest rainfall usually occurs in summer, although rainfall is fairly evenly distributed throughout the year. A dry autumn is not uncommon.
The slopes areas of the State may be classified as sub-humid, and fall into two climatic zones. The northern slopes are areas of summer rainfall with dry spells more frequent in winter and early spring. The southern slopes are areas where most of the rainfall occurs in winter, and where dry spells are common in summer. In both northern and southern slopes areas frosts are common in the three winter months and summer maximum temperatures are high.
The western plains zone of New South Wales has a semi-arid climate. Rainfall is less than 250 mm per annum over much of this land and, moreover, the rainfall is very unreliable. There are big differences between summer and winter temperatures, the summers being very hot and frosts occurring widely in winter.
The extreme north-western corner of the state has such low rainfall that the climate there is classed as arid.
Essay # 5. Soils of Eastern Australia
:
Because soils have been so important to man, he has tried to classify and find names for them ever since cultivation began:
1. The first attempts to name soils were based on texture. Thus soils were first described as sandy loams, or silts, sandy clay loams, clays, silt loams and so forth. These names are still in use because the texture of a soil influences the cultivation treatment it will need, the percolation rate and soil temperature. However the weakness of these names is that they usually refer only to the surface layers of a soil, and we are often very interested in the deeper layers as well.
2. The naming of soils by the vegetation growing on them has been used a great deal in Australia. These names are sometimes useful. Thus land which grows yellow or white box may be suitable for wheat growing; spotted gums usually grow on poor, stony or sandy soils; flooded gum country is usually a good coastal alluvium.
The trouble is that these names may be misleading. Thus land which grows the narrow-leafed ironbark is usually poor, but land carrying the silver-leafed ironbark is often very fertile. Therefore if land is described as “ironbark country”, this does not tell us much about the soil.
3. Another attempt to name soils was according to the kind of rock from which they had been formed. Names such as sandstone soils, granite soils, basalt soils, “trap” or shale soils, limestone soils and slaty soils were used. These names are still used at times and have some value. Thus the granite soils of southern Queensland and northern New South Wales have much in common.
Most basalt soils are red or red-brown clays, and most sandstone soils are open-textured sandy loams.
Yet there are three reasons why naming soils by the rocks which formed them—a geological classification—is not satisfactory:
(a) Soils derived from the same kind of rock, but lying in different positions on a slope, may have quite different features. For example, soils formed from basalts may be red, brown or black according to whether they lie on the top of a hill, on a hillside or at the bottom of a slope.
(b) Soils produced from the same kind of rock, but occurring in different climates, often show great differences. Thus sandstone soils in one climate may be of average fertility, yet in another they may be infertile.
(c) Another reason against a geological classification is that rocks of the same name may vary a lot in the soils which they produce. Thus soft shales may form deep loams, but shales which have been hardened by great heat and pressure may form shallow stony soils.
Great progress in soil classification was made by the Russian scientist Dokuchaiev (pronounced Do-koo-choff) and other Russian workers at the end of the last century. The Russians tried to name and classify soils according to the features shown by the whole soil profile—not just the surface layers.
They believed it was necessary to describe all the features of a profile, such as the presence or absence of soluble salts, presence of calcium carbonate, the colour of each horizon, the depth of the A, horizon and so on. They found that soils could be grouped together according to their profile features.
They also found that climate was an important factor in causing soils to have a certain profile, and that climate seemed to be more important than the nature of the underlying rock. It was a long time before Dokuchaiev’s ideas became known because few English-speaking scientists could read Russian, but the Russian ideas were first used by American workers. Then in 1924 Prescott used the same system in trying to classify Australian soils.
There is much discussion about how soils should be classified, but the ideas of the Russian scientists are widely accepted.
Although no soil classification is perfect, there are a number of important soil types in eastern Australia, and the more common of these are described below:
i. Podsols:
These soils are formed in humid climates where the annual rainfall is at least 1000 mm. Podsols are found along the eastern coast and on some eastern slopes of the dividing range. These are the most mature of our soils. The heavy rainfall has moved a lot of the clay down into the B horizon, and the A and B horizons are very different in appearance. The surface humus is dark but shallow in depth.
There has been so much leaching that iron oxide has been washed out of the A horizon which is a light greyish sandy loam. The B horizon is usually a yellow-grey clay or a grey clay with yellowish patches. The mineral nutrients have been largely washed out and their place taken by hydrogen ions.
Therefore the soils are acid and may be lacking in mineral nutrients such as zinc, potassium, copper, calcium and magnesium. Podsols may also be deficient in organic nutrients especially nitrogen. Because clay has been washed down into the B horizon, podsols are often badly drained.
ii. Podsolic Soils:
Along the eastern side of the dividing range there are some soils which resemble podsols, but which have not received quite as much rainfall. There may be some iron oxide in the surface layers and so the A horizon may be brownish or yellowish. They are similar to the podsols in appearance, but the horizons are not quite so clearly separated, and they may be richer in nutrients than podsols.
iii. Red Loams:
These are sedentary soils formed from basalt rocks. The basalt decomposes into clay, but the colloidal iron compounds in it cause the clay particles to become strongly aggregated. This is why the red loams do not have well-developed profiles even when they are formed in semi-humid climates. These soils have a rich red colour, or are reddish-brown. Those which occur in areas of moderate rainfall are fertile alkaline soils, whereas those formed in humid climates tend to be acid and less fertile.
Red loams occur in the Dorrigo, Batlow, Moss Vale and Guyra districts of New South Wales where they are used in potato growing. The red loams of the big scrub districts of Alstonville and Lismore are less fertile and support dairying. Some of the red loams are deficient in sulphur, and this must be added to them in the form of gypsum or superphosphate. The red loams have a high wilting point owing to their high clay content.
iv. Black Earths:
These are sometimes called chernozems because they resemble soils of that name found in Russia. Black earths have been formed from decomposed basalts in hilly country, transported by water to the plains and laid down there. They contain a high percentage of humus, and are deep black clays.
The profiles are poorly developed because the humus colloids have produced structure which has prevented the clay particles from being moved down by water. Nodules of calcium carbonate may sometimes be found in the subsoil. Large areas of black earths occur in the Liverpool Plains and the north-western areas of New South Wales, and in the Darling Downs and parts of central Queensland.
These soils are very fertile and grow good crops of wheat, linseed and sorghum. However they crack open when dry and require careful management to conserve water for crops. They become very sticky when wet, and black soil roads must be sealed for all-weather traffic.
v. Red-Brown Earths:
These soils are formed in regions of medium rainfall (400-900 mm). There has been enough rainfall to move down some of the finer particles, and the profile is fairly well developed. The dark surface layers lie over a reddish-brown A horizon.
The B horizon is usually darker than the A. The chief feature of the profile is the zone of nodules of calcium carbonate found at the bottom of the B horizon. Large areas of the western slopes of eastern Australia are red-brown earths, and much wheat is grown on these soils.
vi. Grey and Brown Soils of Heavy Texture:
These soils are found in western districts of Victoria, New South Wales and Queensland. They are formed in areas of medium to low rainfall. The profiles are fairly well developed despite the low rainfall. The reason for this is that the presence of sodium salts has dispersed the clay particles and enabled the small amount of rainfall to carry many of them down into the subsoil.
These soils vary a good deal, but the A horizon is always heavy in texture and either grey or brown in colour. There is an accumulation of clay in the B horizon. There has been insufficient rainfall to remove sodium salts completely, and these may occur deep in the subsoil. Where these soils are irrigated, care must be taken not to over-irrigate, or the sodium salts may be brought to the surface.
vii. Desert Soils:
Formed in areas receiving less than 200 mm of rainfall annually, these soils are red-brown in colour with a poorly developed profile. There has not been enough rainfall to remove the most soluble salts which may occur at or near the surface. Salt pans may be found where the surface run-off collects in shallow depressions and evaporates. Because these soils carry a small amount of vegetation they are deficient in nitrogen.
viii. Alluvium:
These are transported soils which have been deposited by running water. They are found as wide or narrow strips along creek and river banks, and are usually deep even loams. They do not have well-developed profiles because there has not been enough time for the formation of distinct layers.
Hence alluvial soils are said to be young or immature soils. They are often very fertile well-drained soils, but those which contain much silt may have poor structure. Alluvial soils are used extensively to grow crops like lucerne, maize, potatoes, cane, vegetable crops and sorghums.
Essay # 6. Soil
Erosion in Australia:
Where man uses virgin lands for animal or plant production, erosion is likely to be quickened. This accelerated erosion is brought about because agriculture changes the environment.
In Australia, grazing animals are often the most important causes of this change, for they denude the land of its protective cover of native vegetation. This is a big problem in the huge semi-arid areas of Australia, where stockowners are tempted to overstock the land. In the more favoured areas, sown pastures may provide a better surface cover than the original native pastures, and, with careful management, animals may not accelerate erosion on these properties.
The clearing of timber leaves the land more open to the effects of wind. This has been shown most clearly in the vast areas of cultivated mallee soils, where erosion by wind has been severe.
Cultivation is a most potent cause of accelerated erosion. As soon as the natural vegetation is removed by ploughing, wind and water are able to remove the top soil more readily. This is especially so on sloping paddocks. If farmers are so unwise as to plough up and down a slope, instead of across it, the furrows act as gutters, along which running water gathers speed.
As soon as land is cleared and cultivated, the amount of organic matter in the soil begins to drop sharply, because the supply has been suddenly stopped. When there is less organic matter, there is less adhesion between the soil particles, and the soil becomes more erodable. Bare soils exposed to the sun and wind may dry out rapidly, and the surface soil becomes sealed by pockets of air in the pores. These soils cannot be wet easily when rain falls, and being dry underneath, are more erodable.
The effects of erosion of top soil are that fertility is lowered, and the land becomes infested with weeds which will tolerate low fertility. In some soils, these effects take a long time to be produced, and this is a great danger. Farmers may not notice the effects of erosion until it has become a major problem.
Essay # 7. Water and Nutrient Management
in Australia:
The chief factor which limits the growth of plants in Australian soils is low rainfall and shortage of soil water. Where streams are available, water may be supplied to the soil by some form of irrigation. In all kinds of irrigation, the water applied should be measured, and care taken to avoid applying too much water.
Where streams have very uneven flow, water may be stored either in earth dams placed in gullies, or in turkey-nest dams on the creek banks. Loss of water by seepage may be prevented by the use of plastic sheeting. Evaporation from the surface of dams may be lessened by the use of cetyl alcohol films.
Where irrigation is not possible, water may be conserved in the soil by increasing intake of water by percolation, and preventing loss of water from the soil. Intake may be increased by keeping the surface in a rough condition with deep ridges to hold the water and prevent run-off. The chisel plough has been useful in bringing this about. The amount of cultivation needed to keep the soil in this open condition will depend on texture and structure.
Silty soils seal over quickly after rain, and may require frequent attention. Some soils along creek banks may become impervious because of flooding or run-off from higher ground during heavy downpours. Contour banks on steep hillsides may increase absorption, and the system known as the Keyline Plan helps to reduce loss by run-off.
In cases where the water table is close to the surface, drainage practices may be necessary to lower the water table. Surface drains are the commonest form in Australia, although porous pipes may be laid in valuable land used for the intensive cultivation of vegetables and other crops. Soils with an impervious clay subsoil may require the use of a subsoil plough, or some other deep tillage implement.
The supply of plant nutrients in a soil must be kept at a satisfactory level. The supply of nitrogen may be increased in two ways. The application of inorganic fertilisers supplies nitrogen quickly, but this is expensive in Australia, and may have a damaging effect on structure.
The nitrogen supply may be increased by adding organic matter to the soil in several ways. The application of animal manures in large amounts is only possible in small areas where valuable crops are grown. Animal manures must be buried to be fully effective. The making and spreading of compost is not possible in Australia except in small areas because of the cost involved.
The best way of increasing organic matter in the soil is through the use of legumes which form part of a rotation. In coastal areas, short rotations using green manure crops may be the best method. Research will someday show us which is the best green manure legume for each district.
In inland areas, the pasture legumes in a longer rotation seem to be the best means of increasing organic matter. Sub clover seems to be the best legume in the south, and white clover and lucerne in the north, but again, research is needed to suggest the best plant for each district.
The great hopes of building up organic matter in the wheat soils by including pasture in the rotation have been dashed by the discovery that, after the pasture has been ploughed under, the wheat crops suffer more from root rots. Research is needed to solve this problem in wheat growing.
When wheat stubble is ploughed under, organic matter is added to the soil, but it is lacking in nitrogen. When wheat is sown, the soil organisms compete with the wheat for the small amount of nitrogen available. Therefore there is not much benefit in ploughing such crop residues under the soil.
Most Australian soils are lacking in phosphorus, and this must be corrected by applying superphosphate. Some north-western areas of New South Wales and parts of Queensland do not show a response to this fertiliser. An important fact to know is that phosphorus stimulates legumes, and these in turn build up the supply of soil nitrogen and produce good structure.
Where other major nutrients are lacking in a soil, they must be added. Sulphur is deficient in some red loams. Land which is deficient in potassium must be rested to restore supplies of this element, or fertilisers may be applied.
In areas where trace elements are deficient, these must the soil. These elements are needed for the healthy growth grazing animals.
Essay # 8. Agricultural Zones of Australia:
Although soils and topography may have important effects, it is the climate which chiefly controls the agricultural industries which may be carried on efficiently in any area. There would be no better way of illustrating this fact than to examine the chief agricultural zones of eastern Australia.
1. New South Wales:
The central and south coasts have much in common climatically and differ from the north coast with its sub-tropical climate. Most rain falls in summer in the north and in winter in the south. In all coastal areas the rainfall is high and the high humidity makes the region unsuitable for wheat growing or sheep raising.
The high rainfall and mild winter temperatures make the coastal districts suitable for fruit growing, dairying, pig raising, and the production of vegetables and certain crops. Sugar cane is an important crop on the north coast.
Coastal topography varies greatly, from river flats to rugged range and gorge country. Soil erosion is a grave problem in some localities where steep lands have been cultivated. The most valuable coastal soils are the alluvial creek and river flats on which trees like flooded gum, grey box and forest red gum may grow.
Some coastal ridges have shallow stony soils on which it is common to find spotted gums. Large areas of the coast have soils formed from volcanic rocks or soils formed from sedimentary rocks like shales and sandstones. Many coastal soils are podsols with yellowish flecks in the clay of the B horizon.
The leaching effect of the high rainfall and the effects of over-cropping have left many coastal soils deficient in plant nutrients. It is common to find that soils lack sufficient nitrogen, phosphorus and potash, while copper, molybdenum and manganese may also be deficient. Coastal pastures usually respond quickly to the application of fertilisers.
The commonest grasses on coastal soils are probably the introduced Paspalum dilatatum and Kikuyu. These grasses are greedy feeders and will soon exhaust soil nitrogen supplies unless legumes or fertilisers are used.
Most coastal farms are dairies, usually about 60 ha in size. Dairies on rich flats may be smaller than this; those on poor hill country are larger. Banana farms are located on steep north coast hillsides facing north or north-east.
Sugar-cane farms are found on river flats along the Tweed, Lower Richmond and Clarence rivers, while citrus orchards are common in valleys of the central coast. Poultry properties are usually less than 2 ha in size. Vegetable farms are also small.
Dairying is the largest primary industry in the coastal districts. Farms are in two zones. Dairies in the milk zone sell whole milk, for which a higher return per litre is obtained than on farms in the butter zone, which sell cream only. The milk zone has been greatly extended in recent years.
The low price of cream for butter making is the main reason why many dairies are not profitable, but low soil fertility leading to low pasture production is another reason. All kinds of agricultural production on the coast will become more productive when it is possible to raise soil fertility by the use of fertilisers and new pasture species.
Between the eastern edge of the northern tablelands and the north coast lies an area or rugged country which is locally called the “falls country”, but which is better called “eastern scarp lands”. It consists of steep, mountainous ridges separated by deep valleys and gorges.
“Eastern slopes” is not a good name for this country, for it is very much more rugged than the western slopes. Waterfalls are common along the streams in the area. There are few roads and the district is very sparsely settled.
The climate is almost the same as that of the north coast, but the rainfall is considerably less and the summer temperatures are higher in the valleys. Soils are similar to those found on the coast, but stony shallow soils are common on the steep hillsides.
Most of this country is entirely unimproved. The native pastures provide suitable stock feed for only part of the year. These facts, together with the lack of good roads and the distance from towns, means that land values are low.
Most properties in this zone are therefore large and the raising of beef cattle is almost the only agricultural enterprise. Because of the high summer temperatures in the valleys, cattle with Indian blood, such as the Santa Gertrudis, have become popular. Hereford and Devon cattle are also popular in this zone.
Except for scattered patches of cultivated river banks, almost no crops are grown in this region. The zone has rich timber resources, particularly of hardwoods like tallow-wood and stringy-bark.
One of the biggest problems in the eastern scarp lands is the prevalence of the dingo, which prevents the raising of sheep in this country. Dingo-proof fences run along the eastern edge of the tablelands, preventing the western movement of these dogs.
Good stock horses and four-wheel drive vehicles are essential on cattle properties in this zone.
The northern, central and southern tablelands have in common a cool upland climate with ample and fairly evenly distributed rainfall. In the north, summer is usually the season of heaviest rainfall and may be followed by a dry autumn. In the central and southern areas winter rains are often the heaviest, but there is no dry season. In all tableland areas cold westerly winds are common in winter.
Tableland topography includes rugged range country as in the Ben Lomond and Lithgow districts as well as large areas of fairly level country. Extensive areas of flat land occur in the vicinity of Goulburn, Marulan and Kentucky.
Tableland soils are usually named according to the nature of the rock from which they were formed. The least fertile of these soils are those formed from “trap” rock, which is the name given to very hard sedimentary rocks. The most fertile soils are the alluviums, found along river and creek banks. The granite soils vary in fertility but some are regarded as poor soils. The soils formed from basalts are chocolate or red clay loams, such as those found near Moss Vale, Orange, Batlow, Guyra and Red Range.
Being in a humid zone, most tableland soils tend to be of the podsolic type and most of them have suffered from the leaching out of plant nutrients. About 90 per cent of the soils in the virgin state are deficient in phosphorus and sulphur and many are also deficient in molybdenum. Potassium and boron are lacking in some soils. Almost all tableland soils are lacking in nitrogen until legumes are established.
The commonest tableland trees are the messmate stringy-barks, red gum, peppermints and boxes. Angophoras are common in some parts and black sallies and snow gums are found at higher altitudes. Wallaby grasses are valuable native species but red grass and bladey grass may invade overgrazed pastures. Paspalum is spreading in the tablelands.
Agriculture on the tablelands is greatly affected by the low temperatures in winter, which cause a slowing of plant growth. No matter how much rain falls on native pastures in winter, pasture growth falls to extremely low levels. The establishment of improved pastures lessens this problem, and it is on the tablelands that pasture improvement has been most successful and widespread.
Aerial topdressing of pastures with superphosphate mixed with clover seed has greatly increased plant production per hectare; it has also brought problems such as bloat in cattle in wethers. As greater numbers of stock are carried on a property, the cost of providing extra yards, fencing and bigger shearing sheds also increases.
Grazing properties on the tablelands vary in size from a few hundred ha to many thousands of ha. Living areas vary from 200-300 ha on rich basalt soils to 1000-1200 ha on poor trap soils.
There are many small farms in parts of the tablelands especially in areas of highly fertile soils. Many of these farms specialise in the growing of crops like potatoes, maize and vegetable crops. Not much wheat is grown because frosts prevent the formation of grain.
The western slopes of New South Wales are a belt of undulating lands lying west of the tablelands. This zone has a sub-humid climate with rainfall varying from 600 mm to about 300 mm. In the southern part of this belt winter rains are the heaviest and dry spells are common in summer; in the northern part the heaviest falls of rain occur in summer, while dry spells are more frequent in winter and early spring. Dubbo, which marks the junction of northern and southern parts of the slopes, lies in an area of uniform rains.
Most of the slopes have a gently undulating topography. Steep range country occurs in isolated areas like the Liverpool, Nandewar and Warrumbungle ranges.
Common soil types of the western slopes are the red-brown earths, soils of heavy texture, sandy loams and black earths of the Chernozem type. In many of these soils nodules of calcium carbonate occur in a band low down in the B horizon.
The most fertile of all these soils are the black earths of the Liverpool plains and the north-western slopes. The red- brown earths are deficient in phosphorus and nitrogen, and many also lack sulphur. The light texture of these soils makes them liable to erosion.
The yellow box is perhaps the commonest tree, but white box, stringy-barks, narrow-leafed ironbark, Angophoras and river red gums are also common. Cypress pine usually grows in sandy soils. Mallees, wilga and mulga grow in the more western parts of the region.
The western slopes are a zone of great agricultural importance. Wheat growing is almost confined to this zone and large areas of oats, lucerne, fodder crops, sorghums and other crops are grown here. Because it grows in winter, subterranean clover has been the pasture plant of major importance in the south. Sorghum aImum, barrel medic and other legumes have been important fodder plants in the north-west.
Although the merino sheep is the chief farm animal of the slopes, this zone also produces large numbers of fat lambs, pigs, beef cattle, poultry and some dairy cattle.
The western plains of New South Wales are more extensive than any other agricultural zone of the State. These vast lands have a semi-arid climate with an average annual rainfall of less than 250 mm. The extreme north-west part of the State has an even lower rainfall and is classed as an arid zone.
The topography of the plains is either flat or very gently undulating. There is a great variation in the soils found in this zone, but many of them share certain features. All are low in nitrogen and most are easily eroded by wind and water. Nodules of calcium carbonate may be found near the surface and salt pans may form in shallow depressions. Red and red- brown are common soil colours.
Although there are certain treeless areas in this zone, trees such as wilga, mulga, mallee, belah and gidgee are widespread. The coolibah is common along watercourses, while saltbush and bluebush form small shrubs. The extent of grass and herb growth depends on the season and varies from luxuriant to extremely scanty. Since the evaporating power of the air is high for the greater part of the year, most annuals do not remain succulent for long periods.
The rainfall of the plains is too low to permit any form of cultivation, and the raising of sheep is the chief agricultural industry. It is not possible to breed sheep here so the sheep are almost all merino weathers. Since much of the annual rainfall is received as patchy storm rains, very large areas are needed for grazing to ensure that each property will have some feed available.
The dry climate means that worm parasites in sheep cause little trouble for the worms cannot complete their life cycle. Wild pigs are a problem along the watercourses.
The major problem of this zone is overgrazing and the serious effects which it may have on soils and vegetation. For instance, many of the valuable saltbushes have been eaten out and are not regenerating properly. There are signs that the soil is eroding more easily in some areas where the cover of vegetation has been reduced.
People could not live in much of this zone if it were not for the bore drains which provide water for stock. The salinity of the water is often too high to permit its use to irrigate crops.
2. Victoria:
Although it is only a little more than 3 per cent of the total area of Australia, Victoria is the most closely settled state, and its agriculture is highly developed. The distribution of agricultural industries is governed mainly by the rainfall. The highest annual rainfalls, of 1000-1100 mm, occur in the eastern mountainous and southern coastal areas, while rainfall becomes less as one moves northwards.
Much of the central and south-western districts receives 630-760 mm, while northern wheat areas receive only 380-500 mm. Winters are generally mild except in the mountainous areas.
Because of the wide variation in rainfall, topography and soils, this intensively farmed state can be divided into eight distinct agricultural regions:
Lying in the far north-west, this is an area of nearly 4.5 million ha of light- textured soils suitable for cropping. Large areas of wheat, oats and barley are grown, but the biggest change in the Mallee is the growth of pasture improvement.
Certain pasture species, especially lucerne, barrel medic and harbinger medic, have played a large part in this pasture development. Two problems of the Mallee are now being solved: soil erosion and the increase of soil salt in the irrigation areas.
The southern portion of the Wimmera is not suitable for agriculture and is a Crown reserve. In the north and central portions are found large areas of fertile clay loams which are well suited to cereal growing. The wider use of improved pastures is not only supporting greater numbers of merino sheep, but is also having a marked effect in raising wheat yields.
Most parts of this district receive a rainfall between 630 mm and 760 mm, most of it falling in winter. Soils vary greatly and include grey sands in the west and south and podsolic soils in the north. Large areas of the district are covered by basalt soils of medium fertility.
Pasture improvement is succeeding in this district, which is well-suited to the production of livestock. Besides large numbers of sheep, the western district also carries dairy cattle, beef cattle and pigs.
The Otway Ranges cause a rain shadow area north of Geelong where only 500 mm falls annually, but falls of 1200 mm occur in the ranges north and east of Melbourne. Soils in this district include grey podsols, red loams, red-brown earths and grey sandy loams. Chief crops include malting barley, potatoes and vegetables, while dairying is the main animal industry.
The most highly productive parts of this area are in the south and west, where the rainfall is between 760 and 1000 mm. Large unoccupied areas in northern and eastern Gippsland are Crown reserves.
Soils in the settled areas include sandy loams and red clay loams. Dairying is the chief primary industry of Gippsland, but beef cattle, pigs and fat lambs are also produced here. The high animal production is possible because of the excellent pastures in the better-rainfall areas.
This large area of flat land has light mallee soils in the north-west and red-brown earths of high fertility in the east. Rainfall varies from 355 mm in the west to 635 mm in the eastern ranges. This district includes the main irrigation areas of Victoria.
Because of this, there is a wide variety of agricultural activities, of which fruit growing is very important. Wheat is the most important crop in this district, which also carries large numbers of sheep and some dairy cattle.
Much of this district is rugged and heavily-timbered country unsuited to agriculture. Most crop production takes place in the fertile river valleys with a rainfall between 500 and 760 mm. Beef cattle are grazed on some of the hilly pastures, while sheep are found on the more level country. Subterranean clover is a useful pasture legume here.
This is a relatively small area of tablelands and slopes, used mainly for grazing purposes. There is also some potato growing and some fruit production.
3. Queensland:
This vast state has more than twice the area of Texas (the largest American State except Alaska), and is equal to the combined areas of Norway, Germany, France, Spain and Belgium. When we consider its advantages of soils and climate, it is clear that the agricultural development of Queensland has barely begun. Not only is the area under crops increasing rapidly, but the greatest developments will come as a result of the improvement of pastures.
Over the whole of Queensland summer rainfall is usually greater than rain at other seasons. Total rainfall varies from 170 mm or less in the south-western corner to over 2500 mm in parts of the far north coast.
There is a very great variety of soils in Queensland. Rich black clay soils of the Darling Downs are suitable for intensive farming, while rich alluvial soils are widely distributed. Poorer soils include the shallow sandy wallum soils of the coastal fringe, and some of the coarse-textured soils of the granite belt.
There are huge areas of red, brown and black clay loams, also light-textured soils, and desert loams. Scientists are discovering the nutrient deficiencies of Queensland soils and this is making possible the rapid spread of pasture improvement. Many cases of deficiency of trace elements, such as copper and zinc, are already known, and when these have been corrected there have been great increases in plant growth.
A feature of many soils in the central and south-western districts is the formation of shallow depressions called “melonholes” or gilgais. The cause of this formation is not known.
Queensland is so vast that in a brief account of it only a few of the more important areas can be mentioned.
The Downs are one of the most intensively farmed areas in Australia. Soils are mostly black or dark brown clays, but silt loams and lighter soils also occur. Besides wheat, important crops are oats, barley, grain sorghum, safflower and linseed.
This area of 5.6 million ha is being rapidly cleared and developed. It extends about 1200 km north from the southern border and up to 480 km inland. Only three quarters cleared at present, it is the largest area of fertile but undeveloped land in the better-rainfall parts of Australia.
Once the clearing was done by axe, but now the brigalow is being cleared by chain and cable or by hormone sprays. Most of the brigalow soils are fertile clays and they can support a very wide range of agriculture.
iii. The Channel Country:
The channel country lies across the south-western corner of Queensland. It is a dry grazing area, most of it receiving less than 250 mm of rainfall.
iv. The Coastal and Sub-Coastal Zones:
These include both fertile and infertile soils, but the whole of this area receives adequate rainfall. The rich alluvial sugar lands of Bundaberg, Mackay, Ayr, Ingham and Innisfail are mostly in areas of high rainfall.
Lotanonis and Desmodium are legumes suited to the infertile wallum soils which can now grow good pastures. Townsville lucerne is a soil- improving legume suited to a wide range of conditions in coastal and sub-coastal Queensland.
This zone includes the Cape York, Gulf and Atherton Tableland areas, the Burdekin Valley and portion of the Barkly Tableland. Progress is being made here in the control of cattle tick, the worst problem of the north, in breeding cattle better adapted to the heat and humidity, and in establishing better pastures. Centro, Siratro and Stylo are tropical legumes suited to parts of this zone.
Central Queensland is a vast area of dry sheep lands receiving between 250 and 500 mm of rain. Much of this belt carries valuable native pastures of Mitchell and Flinders grasses. One problem of this country is large herds of kangaroos.
4. Tasmania:
More than half of Tasmania is unsuitable for farming and at present only about a tenth of the whole area is cultivated.
The heaviest rainfalls occur in winter and early spring, the prevailing winter winds being westerlies. Rainfall varies from as much as 3500 mm in parts of the west coast, 760 to 1500 mm in the north-east district, and 1000 mm in the north midlands to 500 mm in the central midlands.
There is great variation in Tasmanian soils, alluvial soils being the richest. Fertile chocolate loams are common on the north-west coast, while soils formed from sandstones, shales and granites are common in the north-east.
Although many Tasmanian soils are not very fertile, agricultural production will greatly increase when suitable fertilisers are used. Where fertilisers have been used to correct trace element deficiencies in copper, cobalt, boron and molybdenum, the soil fertility has been raised so much that land is being used for cultivation instead of grazing.
The most intensively farmed area is the north-west of the State, where dairying and potato growing are important. Fruit and fat lambs are produced in the Tamar Valley, while the north-east region is used for mixed farming. The commonest crop is oats, but some barley is also grown. Although Tasmania was once the chief wheat producing state in Australia, the area under wheat has declined to about 2400 ha.
There is no doubt that the spread of pasture improvement will not only lead to greater beef, dairy, wool and fat lamb production, but it will so raise the soil fertility that crop production will also increase greatly in this state.
Essay # 9. Crop Production in Australia:
Crop production is the basis of all agriculture, for it is in the green leaves of crop and pasture plants that radiant energy from the sun is trapped and stored as chemical energy in crop products. In many of the advanced countries of the world, plant production has become much more efficient.
For instance in the USA hectare yields of wheat, maize and cotton almost doubled in the ten years up to 1964, due mainly to the greater use of fertilisers. In Australia too, crop yields have been increasing, due mainly to crops being planted in soils which have been made more fertile by pasture legumes.
There have also been very great increases in pasture growth in many parts of Australia, chiefly due to the use of fertilisers. We can expect further increases in crop and pasture yields as modern methods are used to produce better plant growth.
All the crops and pasture plants grown by man have come originally from wild plants, in the same way that the ancestors of our farm livestock were wild animals. Crop and pasture plants have been improved by the selection of better types and breeding from these better strains.
Some crops like wheat, barley and the millets have a long history and have been cultivated by man for thousands of years. Other crops like the potato, sunflower and maize have only been cultivated by Europeans for a few hundred years.
Wheat, barley, rye, oats, millet, rice, peas, soybeans, cane, beets and most of the forage crops came originally from Europe and Asia. From America have come the potato, sweet potato, field beans, sunflower, artichoke, maize and tobacco, while the sorghums and cowpeas had their origin in Africa.
Pasture plants now being used in Australia have come from many countries of the world. Thus buffel grass and Kikuyu grass have come from South Africa, lucerne from the Middle East, some of the Paspalum grasses from South America and the tropical legumes from many tropical countries.
Crops may be classified in many ways. Thus we may group them according to the kind of food they produce, or by the plant family to which they belong, or according to the use which they serve on the farm.
The following list shows how crops may be classified by the product obtained from them:
1. Cereal or grain crops – wheat, oats, barley, rye, rice, maize, grain sorghums, millets, triticale.
2. Legumes grown for seed – peanuts, field peas, soybeans, navy beans, lima beans, lentils, winged beans.
3. Oil crops – sunflower, linseed, soybeans, safflower, castor bean, maize, cottonseed, rapeseed.
4. Low protein forage crops – sweet sorghums, Sudex, grasses, rape, kale, chou moellier, maize.
5. High protein forage crops – velvet beans, mung beans, Dolichos, phasey beans.
6. Root crops – sugar beets, mangolds, turnips, sweet potatoes, cassava.
7. Fibre crops – cotton, flax, ramie, hemp.
8. Tuber crops – potato, artichoke.
9. Sugar crops – sugar cane, sweet sorghums, sugar beets.
10. Drug crops – tobacco, mint, pyrethrum.
11. Rubber crops – rubber tree, Russian dandelion, Guayule (USA).
12. Green manure crops – cowpeas, velvet beans, Dolichos, red clover, phasey beans, mung beans, field peas.
13. Hay crops – lucerne, Sudan grass, millets, oats, pasture.
Sometimes crops are grouped together because of the special purposes they serve on a farm. Cover crops are quick-growing leafy plants like rape which shelter another crop while it is young. Green manure crops are those like cowpeas which grow quickly and produce a large amount of nitrogen-rich leaf and stem which can be ploughed under to enrich the soil.
If it is too late to sow the main crop, a catch crop or quick-growing substitute may be planted. In New South Wales oats, sudan grass and the millets are often used as catch crops. Silage crops such as Sudex, maize and sweet sorghums must produce a large amount of succulent matter which can be used to make silage. Soiling crops are those like maize, Sudex and field peas which may be cut and fed to stock as green feed.
The growing of crops is a most important part of Australian agriculture. Some of the yearly crop production is used locally, but much of it is exported to other countries. Wheat is by far the most important single crop, and Australia usually ranks as the third or fourth biggest wheat exporting country in the world. Other important crop exports are flour, barley, cane sugar, rice, preserved fruits, fresh fruits and dried fruits.
The total area of land used for cropping in Australia in 1977-78 was 16 948 000 hectares, and about 60 per cent of this was under wheat. Figure 19.1 shows the areas of crop lands in each of the Australian states for the 1977-78 season. Figure 19.2 shows the areas of different crops in Australia for the years 1974-78.
If we compare modern crop production in Australia with cropping forty years ago, we see that a number of important changes have taken place.
The greatest change has been in the use of machinery of various kinds. Tractors have taken the place of the draught horse for forty years or more, and farm implements can now be bought to perform every operation in the growing of a crop. Other changes in crop production concern the increasing use of modern methods such as the use of chemicals to control pests and weed growth, the use of better crop varieties, the greater use of fertilisers and the increasing use of irrigation. Farmers are also making use of better rotations which include the use of land which has been under pasture.
In spite of these advances, there is room for much progress in Australian crop growing. More farmers need to understand how to make their soils fertile, for this not only leads to bigger yields but helps in preventing soil erosion. In spite of all the advice and help in planning good cultivation methods which has been given by scientists and agronomists, there are still far too many farmers using inefficient methods.
There are too many who grow the same crop in the soil year after year without maintaining soil fertility; there are too many farms from which the soil is being rapidly lost and too many farmers who do nothing to control the spread of weeds and pests. These examples of unwise farming are not only bad for Australia, but they are also serious for the world. The population of the world is growing fast, and much greater crop production is needed to feed these people. Three steps must be taken in order to increase our crop production in this country.
In the first place there is need for more scientific research in agronomy. Scientists will give us new and better varieties and will discover new ways of increasing crop yields. Then new areas of Australia will have to be developed for cropping. Examples of this are the opening up of new crop lands in Western Australia and the development of parts of the Northern Territory for rice growing and other crops.
The third step needed is to provide extension workers who can not only explain the benefits of new methods to farmers, but who also know how to help farmers to decide to accept new methods. It is important for school pupils to know what is needed because they can later help to bring these changes into being.