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Revegetation for ecologically sustainable dryland farming



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Contents

Glossary of Terms

Major Issues

Introduction

Dryland Farming in Australia

Distribution of dryland farming enterprises

Farmland Degradation

Water erosion

Wind erosion

Acid soils

Soil structure and fertility decline

Salinity and waterlogging

Summary of farmland degradation

Relationship Between Vegetation and Land Degradation

Leaf Area Index

Vegetation cover

Sustaining Dryland Agriculture

Present revegetation strategies

Future revegetation strategies

Government Initiatives

Ecologically Sustainable Development

National Landcare Program

National Drought Program

Rural Adjustment Scheme

Land Clearing Controls

Strategies For Achieving ESD In Dryland Farming

Avenues for change

Making a change

References

Glossary of Terms

agroforestry "is a collective name for land- use systems in which woody perennials (trees, shrubs, etc.) are grown in association with herbaceous plants (crops, pastures) and/or livestock in a spatial arrangement, a rotation, or both, and in which there are ecological and economic interactions between the tree and the non- tree components of the system" (Young, 1986).

coppicing refers to the ability of some trees to produce new stems and branches when the existing branches and trunk have been removed.

dryland farming is the term applied to agriculture which relies solely on rainfall for crop and pasture production.

fallowed land is land that is not in the process of being used for cropping or pasture. A clean fallow is achieved by cultivating the soil each time weed growth occurs. A weedy fallow, as the name suggests, is not cultivated until just prior to sowing the next crop or pasture. A chemical fallow substitutes a chemical weed kill for a mechanical cultivation of the soil.

geoclimatic zones refer to regions with more- or- less distinct geologies, topographies and climate patterns.

groundwater recharge is water that has drained below the root zone of any local vegetation and which is then able to drain downwards to add to the underlying layer of saturated soil.

groundwater discharge is groundwater that escapes into a stream bed, lake or ocean, or through the land surface. Sometimes it is referred to as return flow.

leaching refers to 'washing' of a substance downwards through a soil profile by rainwater or irrigation water. The substance is usually in solution and may progressively displace other chemicals that occur in the soil profile.

recharge event is the term applied to a rainfall event in which groundwater recharge takes place. Not all rainfall events result in recharge. senescence of vegetation refers to the period following maturity of the plant when leaves start to die and fall from the plant. Annuals mature, senesce, and die on an annual basis whilst perennials live for a number of years. The latter may exhibit some senescence during the life cycle, e.g., autumn leaf fall.

sheet erosion refers to a form of water erosion in which water flows across the soil surface as a broad sheet, as compared with a narrow stream. The latter is a precursor to gully erosion.

water repellence occurs in some soils where the soil particles are coated with an organic material (sometimes fungi) that prevents wetting by rainfall. It is similar in action to shower- proofing of clothing. It is common in some deep sandy soils and also in the surface soils of eucalypt forests.

Major Issues

Dryland farming refers to agriculture that is dependent on rainfall for crop and pasture production - as compared with irrigation farming. It has developed at the expense of native vegetation and now occupies some 60 to 70 million hectares of land ranging from cool, wet mountain ranges and tablelands to semi- arid inland plains. About 25 million hectares of that land is regularly ploughed for cropping purposes and is now suffering from various degrees of physical and chemical degradation. Not only is the productive land resource becoming progressively degraded but the surrounding environment is also being affected.

Most forms of land degradation, such as water and wind erosion, acid soils, soil structure and fertility decline, and salinity/waterlogging, are associated with the substitution of shallow- rooted annual crops and pastures for the original deep- rooted, perennial vegetation such as trees. This is due to the fact that trees and shrubs act as physical barriers to wind and water erosion and as biological pumps for the removal of soil water that would otherwise contribute to a problem with rising groundwater tables. The larger, and the more permanent the leaf area available for 'pumping', and the better that leaf material is distributed across landscapes, the better agricultural land is protected from wind and water erosion and a number of other degradation processes.

While techniques for controlling erosion have improved markedly, little attention is being paid to implementing effective methods for controlling groundwater recharge. Waterlogging and salinisation of dryland farms now affects about fifteen times the area affected by irrigated agriculture and this ratio is likely to increase in the future. Thus if land degradation is to be reversed it will be necessary to modify present dryland agricultural systems by engineering plant communities (trees, shrubs, pastures and crops) that more closely simulate the original vegetative structures but which still permit high levels of agricultural production.

Since the Commonwealth and State Governments are committed to a policy of Ecologically Sustainable Development they must now find the means to ensure that dryland agriculture is not only sustainable with respect to production but also with respect to the surrounding environment. So far their efforts have relied on education and demonstration programs delivered through the National Landcare Program. This is not yet proving to be very effective in terms of restoring farmlands and the environment in general.

A part of the problem is that government departments, Landcare and farmers are concentrating their efforts on 'production' without placing due emphasis on the environmental consequences of the so- called sustainable farming techniques.

Although governments are spending considerable sums of money in rescuing farmers suffering from financial hardship this is usually an action of last resort rather than providing the types of assistance that would protect them from the vagaries of climate and market conditions. There is a reluctance on the part of governments to spend public money for onfarm works that could be seen as a gain for private individuals.

Landholders, on their part, also appear to be resisting change. This is probably due to a mixture of ignorance of the environmental consequences of their present landuse practices, and to a lack of available finance to institute change.

Governments and dryland farmers need to develop a realistic vision for the future that will satisfy the criteria for both productive and ecological sustainability. Having done that, agreement then needs to be reached on the types of assistance that may be necessary to achieve those goals. Governments have a duty to the whole of the Australian community to see that environmentally sound farming systems are adopted and supported and should not be satisfied with the present very slow rate of progress.

This paper discusses agroforestry as a means for achieving both ecological and productive sustainability of dryland farming areas. There may be other systems available but all should be examined in terms of the land degradation processes detailed in the paper. Government assistance, in providing the loan capital necessary, would need to be tied to individual landholder contracts and although the suggested solution may be regarded as radical by both governments and landholders it provides a challenge to both parties as to their commitment to Australian land resources.

Introduction

" She's got to blow to grow!" is a piece of practical folklore that has developed in the Murray mallee of South Australia. It refers to the practice of maintaining fallowed land so clear of weeds during the summer and autumn fallow period that the slightest breeze sets the surface soil moving. This formula has worked for a long time and paddocks have been on the move for a long time, covering fencelines with drifting sand. Even today there are farmers in that area who follow this formula and who have trouble with coming to grips with all the fuss being made about the environment.

Two thousand kilometres to the north- east, Hector Todd, a 70 year old Darling Downs farmer recalled his father's farming technique:

"He was told that the trees were a weed and to get rid of them, and he did a great job of doing that, and hardly left a shade tree. The land, the way they farmed it, washed away. I can remember the train being bogged in the silt from farmers' paddocks and silt right across the roads at that time, but no- one seemed to worry about it much. It was an act of God and it happened every year" (Todd, 1990).

It would be surprising if similar stories could not be found in all dryland, i.e., rain fed, agricultural areas of Australia. They probably would all have a common theme, viz., a continuous battle against trees and weeds rather than working with existing vegetation to take advantage of the benefits that accrue from the presence of perennial plant species.

It might be expected that such an important government environmental policy as Ecologically Sustainable Development (ESD) would address this issue. However the National Strategy for ESD in Agriculture, whilst having very specific objectives with respect to agricultural resource management, pest plants and animals, kangaroos and agricultural chemicals, does not address the importance of permanent vegetation in sustaining agricultural lands.

In the meantime, farm land throughout the nation is far from healthy. Internally, soils show fertility decline, increasing acidity, structural decline and poor drainage; externally, soils are becoming more salinised, waterlogged, eroded and infested with weed and animal pests. A human being with equivalent symptoms would be placed in intensive care and close relatives alerted!

It is patently clear that many landholders, and indeed many agricultural advisers, have not come to grips with the problem of how to manage agricultural land in an environmentally sustainable manner. Much emphasis is still being placed on sustainable production alone rather than combining that with care for the surrounding environment. The synergism of the two is sometimes spoken of but generally it appears to be ignored.

The fact that a number of forms of land degradation are associated with the removal of deep- rooted, perennial vegetation cannot be denied by landholders. Whether they are prepared to act on that information is another matter. Governments and some community groups are actively supporting revegetation projects and the preservation of existing native vegetation through a number of natural resource management programs. However much of that effort is being directed towards public lands rather than degraded farmland (Williams, 1995a). Where

farmers are attempting to restore vegetation, their efforts are mostly poorly targeted.

Source: AUSLIG, 1992, unpublished data

Much of the resistance by farmers to calls for revegetation is due to a poor understanding of the real role of permanent vegetation in maintaining a healthy and productive land environment. The same criticism also applies to those framing legislation designed to assist farming to remain a viable and sustainable industry. The result is:

a patchwork of small blocks of privately owned native forest

tree- planting exercises on the tops of hills and along roadways, fencelines and waterways

a patchwork of government assistance programs that tackle the plight of the farmer and not the cause.

This paper explains the fundamental relationships between the degradation of farmlands and the loss of permanent vegetation. It argues that a self- sustaining and environmentally sound agricultural system could be implemented by a strategic revegetation program. Such a system would, however, involve a radical change in land management practices for many landholders. Governments would also have to change their approach and encourage effective vegetation strategies.

Dryland Farming in Australia

'Dryland farming is the term applied to agriculture which relies solely on rainfall for crop and pasture production. For the purposes of this paper, 'pastoral' areas that are too arid for crop production are excluded.

Distribution of dryland farming enterprises

The distribution of Australian broadacre farmlands (Figure 1) indicates that the major agricultural enterprises follow a pattern dominated by rainfall and topography.

The steeper and wetter mountain ranges and tablelands are used for grazing and a limited amount of horticulture. They usually enjoy a reasonably regular rainfall regime but can have relatively short growing seasons for pastures due to lower temperatures. The cold, wet winters are conducive to groundwater recharge and the steeper slopes are highly susceptible to surface and gully erosion.

Undulating land and coastal plains, with an annual rainfall of at least 400 to 500mm, are used for mixed cropping and stock production. Cropped land is inevitably ploughed at some stage and during that disturbed or fallow period it is particularly susceptible to water and wind erosion. Excessive groundwater recharge is a common feature due to the prevalence of short duration annual crops and pastures.

The drier, pastoral zone, or rangeland, is extensive in area. It stretches from Cape York Peninsula through central and northern Australia and includes about one third of Western Australia. Because of the low, and usually irregular, annual rainfall the rangelands are particularly susceptible to wind and water erosion. Damage caused in the past by overgrazing and rabbit plagues have left a legacy of land degradation problems that are receiving only minimal attention. Rangeland are used for grazing and, where water is available, for irrigated agriculture.

The boundaries of these zones are flexible to a certain degree as there are always entrepreneurs who are prepared to gamble on individual seasons - particularly in the drier regions.

Farmland Degradation

Australian soils generally have a low inherent fertility; the soil generating processes (volcanism, tectonic uplift, climate change) that characterise many geologically younger countries have largely been absent for the last 5 000 years. Of the 780 million hectares (ha) of Australian land area, only about one tenth is suitable for agriculture, and a high proportion of that is susceptible to erosion. Constraints on land use for agriculture are shown in Table 1 (Chittleborough, 1986).

Accurate estimates of degraded land are difficult to obtain although the States and the Commonwealth did produce some information in the 1970s (Woods, 1983) and again in the mid- 1980s. Lack of compatibility between the data sets prevented a published report but the Commonwealth Department of Primary Industries and Energy (DPIE) collated sufficient data from those surveys for AUSLIG (1992) to produce a series of land degradation maps for the continent as a whole. The figures are not additive, in terms of calculating the total area of degraded land, as some areas are affected by more than one type of land degradation.

Water erosion

Water erosion is one of the most widespread forms of land degradation and is not just restricted to cultivated lands. Heavy rainfall events with subsequent surface runoff of water can account for soil losses in the order of many tens of tonnes per hectare.

Annual sheet erosion losses from forested and pastured lands are likely to be less than 1 tonne/ha whilst from a bare cultivated paddock it could be as high as 70 tonne/ha. Extreme rainfall events along the north coast of Queensland have resulted in losses as high as 3 800 tonnes/ha from cultivated sugarcane land (Rose, 1993).

Since 1 tonne of soil is equivalent to 1mm of soil over an area of 1 hectare, it can be seen that agricultural lands are disappearing at a rate of 1 to 70 mm per year which is 50 to 3 500 times the rate of soil formation.

The importance of this soil loss is not only related to a reduced depth of soil and off- site contamination but also to a large loss of nutrients associated with the soil particles. It has been estimated (Gutteridge, Haskins & Davey, 1992) that about 940 tonnes of phosphorus and 6 740 tonnes of nitrogen enter the Murray- Darling river systems from diffuse (i.e., non- specific) sources in an average year. This would mainly be from soil eroded from agricultural land.

Another form of water erosion is gully erosion. This also can remove hundreds of tonnes of soil material per year from a single gully. As the sidewalls and head of the gully collapse, the gully widens and extends further upslope. Hilly land tends to be more susceptible because of the faster downslope flow rates of the water but many flat farming areas are criss- crossed with gullies. Apart from the soil loss and pollution of downstream areas, gullies create a considerable problem for movement of agricultural machinery.

One system of landuse that is effective in controlling water erosion is a form of agroforestry known as 'cell', or 'alley' farming. This consists of planting strips of permanent vegetation (preferably around a contour line) and farming in between. Since the severity of sheet erosion depends on the rate of water flow, the strips of vegetation act as barriers that markedly reduce the rate of flow and the development of channels. Any soil that does move is retained within the paddock. It is a land use practice that has a lot of merit and will be referred to again in later sections.

A variant of alley farming is 'strip cropping' which has the same contoured strips of agricultural land but does not include bands of trees. It relies on alternate strips of pasture to intercept any soil washed downslope from the cropped land. For reasons that will become apparent in a later section, this form of conservation farming is only partially successful with respect to land degradation as a whole.

Wind erosion

In geological terms, wind has been a significant factor in the formation of our landscapes. Over the last 2 million years there has been a number of arid phases, the last being about 15 000 years ago. The sand dunes of the Murray mallee, the gypsum dunes on the eastern side of most dry salt pans, and the dunefields and stony gibber plains of central Australia are all testimony to massive amounts of wind- blown soil.

In present times, human activity has accelerated the frequency of duststorms by exposing large areas of bare soil during the hot, dry summer period. This practice of bare fallowing was originally carried out to control weeds and to conserve soil moisture for the subsequent winter crops. However, given chemical fallowing techniques, the practice is no longer necessary nor desirable. The incidence of major duststorms is often associated with periods of drought and it is not at all uncommon for the Southern Alps of New Zealand to receive a coating of Australian dust.

Once wind speeds are sufficient to move a soil particle it can travel in three different ways. It can creep along the soil surface; it can hit another particle and bounce up into the air and become caught up in the wind ( saltation); or, once it is suspended in the air, it can travel long distances before coming back to ground. Thus the erosion process consists of moving soil over distances of a few metres at a time to hundreds of kilometres.

Soil particles of greater than about 0.5mm diameter are not readily caught up by wind. Hence a soil with a good, stable aggregate structure (aggregate sizes of 2 to 5mm) is less susceptible to wind erosion than a powdered, structureless soil. The latter can result from excessive cultivation, nutrient depletion and also the physical impact of stock hooves. A line of sheep strolling towards a watering point is nearly always accompanied by a mist of dust as their hooves powder the chosen track into a powder. Tractors pulling cultivation equipment around paddocks are also commonly accompanied by clouds of dust - particularly when more powerful and faster machinery is used.

Soils can be totally protected from wind erosion by the maintenance of a good cover of vegetation. However once cover is reduced to less than 40 to 50 percent of the soil surface then wind can mobilise soil particles. Even the retention of dry crop stubbles can eliminate most wind erosion. Stubble retention and direct seeding into land with a stubble cover is in direct contrast with earlier practices of clear fallowing. In the latter, stubble residues were grazed and burnt soon after harvest and the land was then ploughed and repeatedly cultivated during the following months in preparation for the next autumn sowing. The wisdom of the day was that weed growth needed to be eliminated to conserve soil moisture and that any soil crust that developed after rainfall needed to be broken up to prevent loss of soil water by capillary flow to the atmosphere. Undoubtedly both of these objectives were achieved but at an enormous cost in terms of wind and water erosion.

As mentioned with water erosion, the shorter the run for an erosive force the less overall impact it has on the landscape as a whole. Thus the alley farming technique described has a further benefit with respect to wind erosion.

DPIE (1991, unpublished) has estimated that lost production from wind erosion costs about $3.6 million each year. According to a report in The Sydney Morning Herald of 27 May 1994, dust storms then occurring in South Australia and Western Victoria removed 20 million tonnes of soil together with an estimated $30 million worth of nutrients.

Acid soils

One of the unexpected consequences of the superphosphate - subterranean clover revolution has been an increase in soil acidity beneath longterm pastures, particularly in the cooler and wetter agricultural lands. This is caused when nitrate- nitrogen, produced by bacterial nodules on clover roots, is leached down the soil profile. As the nitrate moves through the profile it forms very dilute nitric acid, which over a period of years causes the soil to become acidic. The more acid the soil, the greater the tendency for aluminium, iron and manganese to come into solution and poison plant life.

In 1991 DPIE estimated production losses from acid soils at greater than $134 million per year.

There are some agronomic solutions available. For example, deep- rooted perennial grasses may be grown with clovers so as to capture some of the deeper leaching nitrate. However the maintenance of such pastures requires a high level of grazing management and this is not always available.

Acidity can be offset by the application of agricultural lime (calcium carbonate) but rates of less than about 4 tonnes per hectare have only minimal effect. There is also a problem of incorporating lime down the soil profile as it is rather insoluble and hence is only slowly leached downwards by rainfall. The cost of about $50/tonne and the necessity of periodic reapplication means that it is not a cheap ameliorative. Having said that, there is still no doubt that in the long run liming is the most effective and environmentally sound strategy available.

The use of acid- tolerant plant species is another approach that can be used and there are in fact a number of acid- tolerant variants of native grass species. This approach is being trialed in the uplands of six catchments in the south- eastern sector of the Murray- Darling Basin by landholders who have embarked on a 3- year program of selection and performance testing of local grass species in upland areas known to have a soil acidity problem.

It is also possible that genetic engineering techniques may in the future provide high yielding, acid tolerant, perennial pasture species.

Soil structure and fertility decline

Soil structure refers to the arrangement of the sand, silt, clay and organic matter particles that go to make up 'soil'. A good soil structure is one in which the particles are bound together to form stable aggregates as compared with just separate particles. Aggregates range in size from less than 1mm diameter to greater than 5mm. A well aggregated soil has a relatively high proportion of coarse pores between the particles and aggregates which then allows free movement of air and water within the profile. A poorly aggregated soil has a high proportion of very fine pores that restrict air and water movement which makes it difficult for plants to extract water and nutrients.

The main bonding agents in soil aggregates are large, multi- branched organic molecules that have points of attachment to a number of soil particles. These molecules (polysaccharides and polyuronides) are the by- products of soil micro- organism breakdown of organic matter in the soil. They give the aggregates a certain degree of flexibility with respect to mechanical shock, including the shock of rapid swelling after wetting by rain or irrigation. If the bonds are broken they do not readily reform and the individual particles are then susceptible to erosion or they pack together to form a poor structure.

Other bonding agents such as iron and aluminium hydroxides are important in some soils but they are quite inflexible and are relatively easily shattered.

Thus the essence of producing a good soil structure is the maintenance of a high population of micro- flora and fauna (bacteria, fungi, worms). To achieve this, a supply of readily utilised organic matter is required. In the past this was achieved by green- manuring, i.e., deliberately growing a leguminous crop and then ploughing it back into the soil. With the pressure for farmers to increase production, green- manuring has largely been abandoned except for the revival of a relatively small number of 'organic farmers'. The latter, as well as cashing in on a niche market for health- food adherents, are of course improving the capital value of their land and protecting it from many land degradation processes.

Salinity and waterlogging

Salinity has been a focal point of Landcare activities in many parts of the country. Salt scalds caused by the accumulation of soluble salts at or near the soil surface occur in both irrigated and dryland farming areas (Williams, 1995b). The cause is the same, viz., the discharge of groundwater through the soil surface and evaporative concentration of the salts contained in that groundwater. Even good quality groundwater can cause salt scalds by this process.

If the rate of groundwater discharge through the soil surface is faster than evaporation at the soil surface, then salt does not accumulate. Instead it just becomes waterlogged. Thus salinisation and waterlogging are simply part of the same hydrological process and are differentiated by the rate of discharge. They both result in the loss of productive agricultural land.

The reason for groundwater discharge is that present landuse practices allow too much water (rainfall, irrigation) to enter the soil profile. If it drains down past the depth of plant roots then it cannot be captured and transpired by the plants. At that stage it becomes known as 'recharge water' and will continue to drain downwards until it joins up with an underlying watertable. If recharge is excessive then the groundwater cannot discharge rapidly enough into adjacent streams and gully lines to equal the rate of recharge. The only direction the water can then take is vertically upwards, i.e., the groundwater table rises.

Once the watertable is within 1 to 2m of the soil surface water can escape to the atmosphere by capillary action (see Williams, 1995b for more details). As the water evaporates soluble salts are left behind at the soil surface and in the root zone, with the result that most pasture plants are killed. Once the vegetative cover is removed then the soil surface is exposed to the erosive forces of water and wind, as described above. Since we have no control over incoming rainfall it is essential that a large proportion of water entering the soil should be captured by plants. In a natural vegetation system it is common to find mixed plant communities consisting of trees, shrubs and ground cover (grasses, legumes, etc.). The ground cover vegetation has relatively shallow roots but responds rapidly to water inputs. Water escaping past that root zone is then available to the deeper rooting shrubs, and eventually only to the trees with their deeper root system (Figure 2). It is a natural, well engineered water harvesting system that only allows a few percent of the total water intake to reach the groundwater table. In other words there is a balance between recharge and the capacity of the underlying groundwater systems to discharge into streams and oceans.

With the advent of extensive clearing of trees and shrubs for agricultural purposes the water balance has been upset - particularly in those catchments in which groundwater has a limited capacity to drain into the sea. For example, the Murray- Darling Basin and the wheatlands of south- west Western Australia have very restricted groundwater drainage. Within periods ranging from 10 to 40 years or more, individual groundwater systems have been, and still are being, stressed to the degree that they now discharge through the soil surface. Salinisation appears to be accelerating throughout many dryland farming catchments and we may still be seeing only the tip of a massive land degradation problem in the future.

Counter measures are mainly based on improving vegetative cover, but largely by the use of deep- rooting perennial pasture species such as lucerne or phalaris. Other soil properties, such as fertility and acidity, impact on the vigour of plant growth and hence the effectiveness of such strategies is by no means assured. This is not to say that the use of perennial pastures is a poor longterm strategy - it is simply a warning that land degradation is likely to continue, albeit at a slower rate. In fact, given that long duration improved pasture phases are not attractive to many farmers, there is every likelihood that reliance on perennial pastures alone will fail over the longterm.

Summary of farmland degradation

One or more of the land degradation processes described above affects every dryland farm in Australia. This is a sobering thought and one that should exercise the minds of governments as well as individual landholders.

Wind and water erosion processes are well understood.. Both increase in direct proportion to the degree to which bare soil is exposed to these mechanical forces. The solution lies in the maintenance of vegetative cover and reducing the linear distance over which either force is permitted to act upon.

Likewise, soil structure and fertility decline increase in direct proportion to the frequency of mechanical disturbance and cropping. The solution lies in much wider crop/pasture rotations than are presently being practised.

Induced acidity of soils is an unexpected consequence of what has until recently been regarded as an ideal agronomic practice. It, together with the once highly promoted practice of bare fallowing, are classic examples of how agricultural research does not always provide infallible recipes for increased agricultural production. Other agronomic solutions are being sought as a cheaper alternative to known chemical ameliorants.

Salinity and waterlogging are increasing at an alarming rate and are no longer just the province of the irrigation industry. Dryland salinity affects about fifteen times more agricultural land than does the practice of irrigation and this proportion is likely to increase in the future. Governments are spending hundreds of millions of dollars annually on supporting the irrigation industry and in attempting to solve its problems whilst only tens of millions of dollars are being directed towards solving dryland salinity.

The remainder of this paper is directed at explaining the importance of perennial vegetation as a solution to land degradation induced by dryland farming and the manner in which government policies could be altered to address that situation.

Relationship Between Vegetation and Land Degradation

All of the land degradation processes described above are associated with the excessive removal of deep- rooted, perennial vegetation (trees, shrubs) from the landscape. The underlying cause can be summed up in two plant parameters, viz., the Leaf Area Index and vegetation cover.

Leaf Area Index

Leaf Area Index (LAI) is simply the ratio of the total area of a plant's green leaves and stems divided by the area occupied by the plant (Figure 3a). Typically, the LAI of a plant (or paddock of vegetation) increases from near zero at plant emergence to a maximum at maturity, and then falls away again as the leaves die and wither away (Figure 3b).

The significance of the LAI value is that one hectare of pasture, crop or forest can represent many hectares of leaf surface, all of which transpires water from the soil. In other words the LAI is a measure of the biological pumping capacity of the vegetation and its potential to control groundwater recharge. It is also a measure of the capacity of vegetation to physically protect the soil surface from the impact of wind and water.

An annual crop, such as oats, can develop a LAI as high as 5 or 6, i.e., a leaf area of 5 to 6 ha per ha of crop but only for a relatively short period of 3 to 4 months. Once the crop has matured and been harvested for hay or grain, the LAI drops to zero. A perennial, such as lucerne, can also develop a high LAI before being grazed or cut for hay. However it immediately recommences growth so that the LAI again increases and, given careful management, a lucerne pasture can maintain this cycle over a number of years. Indeed, the longer such a system operates the more improvement can be expected in soil structure, soil stability, and soil fertility, as well as control of groundwater recharge and erosion.

The LAI of a healthy lucerne pasture is roughly equivalent to that of a forest so in terms of potential for extracting water from the soil, the two vegetation systems are not dissimilar. The main difference lies in the frequent harvesting of leaf material from the pasture.

Vegetation cover

The natural vegetative cover of Australia has been estimated and mapped by examination of aerial photographs, satellite imagery and field observation (Carnahan, 1976; Graetz et al, 1995). In 200 years of European settlement, forest cover has been reduced by about 50 per cent and woodlands by about 33 per cent (Boden, 1995) in order to make way for agricultural enterprises. This represents an enormous permanent loss of leaf area and potential for transpiring soil moisture.

Of equal importance to the actual loss of leaf area is the fact that it has been totally removed over very large areas. Such remnants as do remain in agricultural areas tend to be isolated trees within paddocks, narrow strips along public roadways and forest and wildlife reserves. This uneven distribution results in very poor control of groundwater recharge as the perennial vegetation has only a limited zone of influence with respect to capturing incoming rainfall before it can gravitate down to the watertable.

Figures 4a, b illustrate two situations; one corresponding to the general practice of planting or leaving trees only along fence lines, the other with a more 'natural' distribution. Both result in cones of soil water extraction which then act as a buffer to subsequent rainwater inputs by increasing the capacity of the soil to store water within the root zone. The fenceline distribution leaves large areas where there is little or no control over recharge whilst the more evenly distributed trees, create a situation in which the overall effect is equivalent to a general lowering of the saturated zone (watertable).

The effectiveness of the fenceline situation in controlling groundwater recharge obviously depends on the dimensions of the paddock. The larger the paddock the less effective the vegetation, although this could be largely offset by the presence of a vigorous, deep- rooted, perennial pasture within the paddock. However any cropping phase would remove that extra protection. The evenly distributed tree system would also be improved by the presence of a deep- rooted perennial pasture but it provides a more effective buffer of unsaturated soil to cope with a cropping phase or an unusually large recharge event.

It is worthwhile examining naturally occurring woodlands and open forests as a vegetative system since they largely controlled groundwater recharge and protected the landscape from water and wind erosion. Normally they would have contained anywhere from 100 to 600 trees per hectare, with a projected foliage cover of 10 to 60 per cent of the land area. In other words, at least 10 percent of the total landscape was occupied by perennial vegetation and this vegetation was evenly distributed across the landscape. Wetter areas had higher tree densities.

Such a scenario provides us with a vegetative model that worked and if we are to substitute other types of vegetative communities then the important features to remember are that the natural system contained:

a minimum of 10 percent tree cover, depending on the climatic zone

an even distribution of that cover.

It is, of course, not economically sensible to say that because the original vegetative model appeared to work well that we should return the large areas of cleared landscape to exactly the same situation. However it should be possible to engineer a biological solution that can mimic the environmental protection provided by the original and yet allow a high level of agricultural production to take place at the same time.

It is unlikely that a single tree density would suit all geoclimatic situations or that a single tree planting strategy would suit all agricultural enterprises. But the original vegetation communities provide a reasonable guide to the amount and distribution of permanent leaf area that is likely to be required, ranging over the wetter to the drier parts of the continent.

Sustaining Dryland Agriculture

A distinction needs to be drawn between 'sustainable production' and 'sustainable agriculture'. There appears to be a deliberate policy amongst Landcare and State Department officers to concentrate their effort on the former and to ignore the latter - at least publicly.

Landowners have for some years been encouraged to construct Whole Farm Plans in order to match land capability with particular farming activities and so optimise production. Thus instead of retaining paddock designs based simply on traditional survey subdivision patterns (north- south, east- west), different soil types and topographies are treated as different management units. In terms of production goals there is a lot of sense in this practice and it has the further advantage of focussing the landowners attention on long term goals rather than short term seasonal problems.

The Whole Farm Plan system has been extended by a Property Management Program (PMP), sponsored within the Commonwealth's National Landcare Program. This is designed to improve all aspects of farm management not just land use and cropping practices. Thus emphasis is now being placed on the financial management of a farm as a business, and on the social aspects implicit in a highly variable family- income situation.

The Property Management Program, like Whole Farm Planning is a valuable aid to improving farm productivity. However it appears that only minimal attention is being paid to landowner responsibilities with respect to their own and the wider environment.

A Land Management Task Force was set up by the Commonwealth Government in January 1995 to examine the operation and effectiveness of PMP. It was due to report in June 1995. Surprisingly, of the six terms of reference, not one mentions ecological sustainability.

The PMP and Whole Farm Plan Programs provide an excellent opportunity to educate landholders on the important role of vegetation in improving productivity as well as protecting the surrounding environment. Reduced groundwater recharge leading to salinity/waterlogging control, improved erosion protection, and improved stock shelter all add up to protection of the landholder's primary resource base - the soil. It would be surprising if productivity gains from these factors alone did not more than compensate, in the long term, for the cost and effort required in re- establishing permanent vegetation. Then on top of that there would be any number of secondary enterprises, such as:

coppicing species that favour periodic harvesting for firewood, charcoal, pulpwood, eucalyptus oil etc

tree crops of fruit and nuts

rare species suited to furniture manufacture

species suited to the fresh and dried flower markets

mixed species suited to a range of wildlife communities

fodder species, such as some acacias, casuarinas, saltbush, bluebush, tree lucerne, and so on.

Present revegetation strategies

Unfortunately, in the adoption of 'best bet' practices during the birth of Landcare in the mid- 1980s, groundwater recharge was associated with rocky hilltops to the exclusion of most other parts of the landscape. The assumption was that because water infiltration rates are relatively high in shallow, stony soils (such as found on hilltops) that this meant that recharge into the underlying groundwater system was equally high. This is not always so due to the nature of the underlying rock material. Also it ignored the fact that hilltops represent only a small proportion of the landscape. Even if the remaining land does have relatively low recharge rates it probably contributes more to rising groundwater tables than hilltops simply due to the total area involved. Landholders were led to believe that revegetating hilltops would solve their groundwater recharge problems, yet 10 years down the track this is not the case. Equally disappointing is the fact that similar advice is now being advocated for the revegetation of 'break of slope' situations, i.e., the lower part of a hillslope where it meets the broad valley floor. Of course, there is nothing wrong with revegetating either or both landscape units, as it will inevitably have some benefit. But, for the reasons discussed above, it will not solve the groundwater recharge problem.

Such poor advice will also, in the future, increase the number of disillusioned landholders and lower the credibility of departmental and Landcare officers. Environmentally concerned landholders tend to a philosophy of every tree helps. However one might equally say that bailing out a sinking ship with a teacup was 'helping' but it would not prevent the ship sinking. The difference in the analogy is that the teacup exercise might hold off the inevitable long enough for help to arrive but in the case of farmland there is no rescue ship on the horizon.

Another problem is that many landholders are not prepared to make major changes to their agricultural practices. They, and their forefathers, have spent many decades 'battling' regrowth of native vegetation. Even today brigalow and mallee species are still demonstrating a remarkable resilience to the continuing attacks of landholders. On those farms where revegetation is presently taking place it is largely on the basis of planting trees where they will cause the least inconvenience, i.e., on stony hilltops and along fencelines. It is unlikely that an effective 'revegetation ethos' will be generated amongst landholders until they are convinced that farming 'whole landscapes' is a more profitable enterprise than farming 'paddocks'.

The One Billion Trees (OBT) and Save The Bush Programs (STB) are the main vehicles for National Landcare Program vegetation strategies. Most of the OBT effort is directed at restoring vegetation on public lands but Greening Australia (one of the main brokers in the Program) will contract to plant on private farmland. The STB Program operates at the other end of the vegetation management system by persuading landholders and Local Government to preserve remnants of native vegetation. Such areas represent an important source of genetic material for future revegetation projects.

Both Programs are administered by the Australian Nature Conservation Agency with contributions to OBT and STB in 1993/94 being $5.4 million and $2.4 million, respectively. Greening Australia, which has developed a considerable expertise in various seed collection and revegetation methods, receives additional government funding from a variety of sources and had an overall 1993- 94 budget of about $12.5 million.

Future revegetation strategies

If, as suggested, much of the existing revegetation advice is not going to produce ecologically sustainable development, then a compromise is required that allows cropping and perennial vegetation to co- exist to the benefit not only of the landholder but to the environment in general. Such a compromise can be achieved by a system of agroforestry.

The advantages of an evenly distributed arrangement of trees and shrubs have already been described but in many ways such a system is impractical. First, it would mean providing individual protection for each tree or clump of trees, particularly during the establishment phase. Second, although it suits a grazing enterprise, it would be a very awkward arrangement for cropping. Third, it would not provide the same degree of protection against water and wind erosion as can be achieved with continuous bands of vegetation.

The other main option is to use lines of trees, but with much smaller paddock dimensions. Such a compromise already exists in the form of 'alley', or 'cell' farming, depending on local terminology. This is illustrated in Figure 5 and in the frontispiece. The strips of permanent deep- rooted vegetation provide the perennial biological pumps necessary for controlling groundwater recharge. The land within the cells would still be available for pasture and cropping enterprises but with more encouragement given to longer pasture/crop rotations. An example would be to crop any one cell only two years in five, with perennial pasture in the remaining three so as to maintain a maximum LAI and to help build up soil fertility. However other rotation patterns could be used depending on market conditions. It would also allow an easily managed spread of agricultural activity across the landscape by utilising alternate strips at any one time.

Other advantages associated with alley farming include wind and water erosion protection, more productive grazing, a second enterprise (timber, fodder reserve) and a more flexible landuse system.

There would also be an incentive for changing back to agricultural machinery with smaller axle loadings as heavy, modern machinery is the cause of a hidden form of land degradation, viz., soil compaction with a consequent loss of soil structure and reduced water and air movement within the soil. For example the very heavy axle loadings associated with modern harvesters result in soil compaction to such an extent that subsequent ploughing requires a doubling of diesel consumption (Tullberg, 1990). This takes place every time a paddock is cropped and the problem will not be redressed until a change is made to smaller machines.

Disadvantages of alley farming include the costs of establishing and protecting the revegetated strips, changing or adapting machinery to suit relatively narrow 'paddocks', and a probable reduction in overall cropping area in any one year.

Given the previous discussion on the effectiveness of strips of trees in controlling groundwater recharge, an informed guess at desirable paddock dimensions can be made. Using a 1 ha (100m x 100m) unit of land as an example, a 10 percent land cover with trees or shrubs would then consist of 10m of vegetation and 90m of farmland. A 20m strip of trees would leave 80m of farmland, and so on. This might seem an extraordinarily narrow paddock to a broadacre farmer but certainly not impractical with respect to machinery manoeuvrability. The frontispiece shows an example of alley farming in Western Australia, using Tagasaste sp (tree lucerne) as a fodder tree crop (photo courtesy WA Dept. Agriculture).

The tree line is likely to produce a zone of groundwater recharge protection of about 20m on either side, so at least 50 percent of the area would be protected. Wetter and colder areas, with a high potential for groundwater recharge and water erosion might require even narrower strips of agricultural land. In terms of cost, a major item would be fencing materials. Each 1 ha land unit would require about 200m of fence, regardless of the width of the treed area. At present prices this would cost about $300 for materials alone. Direct seeding or seedling costs for the same 1 ha unit of land would cost about $50 to $150, respectively. An overall figure for a typical 600 ha farm would then be around $240 000, excluding labour. Given the 25 million ha that is regularly cultivated, the immediate target figure, nationally, would be of the order of $10 billion. A further 40 million ha is not cultivated regularly but still contributes to groundwater recharge and so cannot be excluded from longterm rehabilitation plans.

Any such revegetation program would be spread out over a number of years, or perhaps even decades, so that the large capital cost could also be dispersed over time. Of course, the fencing materials could be reused when all the trees grew tall enough to allow sheep and cattle grazing. There are now some years of experience with alley farming in Australia. Approximately six percent of 1049 respondents to an Australia- wide questionnaire reported that alley farming was being used to combat salinity and/or wind erosion (K. Nicholls, CSIRO, pers. comm. 1995). However there is still no clearcut conclusion of the cost/benefit ratios that can be achieved. Popular articles in agricultural magazines have extolled the environmental and production benefits but have provided little economic analysis. Most assessments have concentrated on single issues such as erosion control, animal production, or controlling salinity (Prinsley, 1991; Gutteridge, 1990). There is an urgent need for an assessment that includes not only productivity factors but also all of the soil and groundwater properties described previously.

Since all Australians are stakeholders in this country, any cost/benefit analysis should also recognise the value that the community as a whole places on an environmentally healthy landscape. It is not just a matter of interest to individual landholders and government economists.

Government Initiatives

Governments at both Commonwealth and State level have actively supported dryland agriculture over many decades. Producers have received a bewildering array of subsidies over the years in the form of tax concessions, commodity price stabilisation schemes, and direct subsidies for nitrogenous and phosphatic fertilisers. The Sir John McEwen philosophy of 'all- round assistance' to industry bred an agro- political system that saw assistance programs become a part of farm life (Business Review Weekly, 1990). This lasted from the late 1950s until the early 1970s. Much of that patchwork approach has now been removed although existing policies are still flexible enough for governments to make short- term responses to unusual circumstances.

Apart from strictly economic interactions with the farming industry, Governments have also supported world class agricultural and soil conservation research through such institutions as CSIRO, universities, and State Departments. The main government programs impacting on dryland farming are now: Ecologically Sustainable Development, National Drought Policy, Rural Adjustment Scheme and Landcare. Natural Resource Management (Landcare) costs in the vicinity of $1 billion annually. The Rural Adjustment Scheme costs about $175 million and drought relief (although climate dependent), has cost about $ 560 million since 1991. State drought aid is additional to this figure.

It would seem sensible to examine these programs to determine whether they offer any potential for encouraging a revegetation scheme.

Ecologically Sustainable Development

A policy of ecologically sustainable development (ESD) was adopted by the Council of Australian Governments (COAG) in 1992. This is an unquestionable commitment on the part of governments to pursue ESD in all aspects of the economy including agriculture. Although not included in the final ESD policy the following objectives were identified by the Working Group on ESD for Agriculture (1991):

maintenance of longterm productivity

improved system resilience and stability.

In particular it placed emphasis on repairing the resource base and developing an understanding of 'agro- ecosytems' at national, regional and farm levels.

An important issue arising out of the National Strategy for ESD is a commitment to prepare regular State of the Environment (SoE) reports. Given that the latest comprehensive set of data on land degradation in Australia is now a decade old, the first SoE report, due in early 1996, will be of considerable interest. This will be followed up by an 'independent ' review by the OECD, under its Country Review Program.

Australia has a number of international obligations to report on land and environmental degradation. These include; The Convention of the World Meteorological Organisation, The Framework Convention on Climate Change, The Convention on Biological Diversity, and Agenda 21 (United Nations Commission on Sustainable Development).

National Landcare Program

The National Landcare Program places considerable emphasis on education as a means for persuading farmers to implement sustainable farming practices and for the preservation of soil., water and vegetation resources. Whole Farm Planning and the Property Management Program are important components of the education system. No doubt many farmers have gained a lot of valuable information but its application depends very much on the availability of personal finance and willingness to change. The principal incentive being offered by governments at the moment is a taxation concession for certain on- farm soil and water conservation activities. At this stage it could not be claimed that there has been a significant national improvement in farmland as a result of Landcare.

The One Billion Trees (OBT) and Save The Bush Programs (STB) have been mentioned previously. Although one of Greening Australia's main objectives of creating 'ribbons and corridors of green' across Australia has many laudable aspects it is poorly targeted with respect to restoring degraded farmlands. The STB Program is an important initiative in preserving a wide spectrum of native vegetation provenances. The fact that many of the remnants of native vegetation that still exist on farmlands is probably due to unsuitable soils for agriculture does not really matter. It is important that they should not just be regarded as 'unproductive scrub'.

National Drought Program

The National Drought Program (NDP) has been reviewed in detail by Burdon (1995). The parts that are relevant to this discussion concern taxation incentives in the form of an Income Equalisation Scheme and Farm Management Bonds. These are designed to even out the highly variable income received by farmers due to climatic and market factors. Other taxation concessions concern preparations for drought, e.g., fodder and water supplies and minimum cultivation equipment.

The NDP also includes a Farm Household Support loan system to help meet living costs during periods of low or negative farm income. In cases of exceptional hardship a Drought Relief Payment is made through the welfare system.

One new aspect of loan interest subsidies granted under the NDP is that they are, to a degree, tied to agreed landuse practices.

Rural Adjustment Scheme

The Rural Adjustment Scheme (RAS) (see Burdon, 1993, for a detailed review) now includes drought assistance, whereas before it was administered under the National Disaster Relief Arrangements scheme. RAS is now more focussed towards assisting farmers to run their enterprises on business principles rather than providing assistance out of an historical empathy for Australian 'battlers from the bush'. Importantly, loans and interest subsidies for debt reconstruction are being targeted at those landholders who can demonstrate a good potential for achieving a viable enterprise.

Land Clearing Controls

The South Australian Government, after several earlier versions, now has a Native Vegetation Act 1991 to control the clearance of native vegetation. It provides assistance to landowners in relation to the preservation and enhancement of native vegetation. It has not been particularly popular with landholders and the compensation measures have had to undergo a number of changes to make the system workable.

In 1989 the Victorian Kirner government approached the issue of land clearing by regulation. The legislation is still being reviewed with the aim of making it more flexible with respect to different geoclimatic zones.

The Queensland Government has floated the idea of a ban on broadscale tree clearing as that State has the dubious honour of having the most rapid and sustained rate of clearing for agricultural purposes in Australia. For example, it has been estimated (DEST, 1995) that between 1983 and 1993 there have been about 500 000 ha/year cleared , Australia- wide, for agricultural purposes. Of this, 300 000 ha/yr occurred in Queensland. The proposed legislation is however, only planned for Crown and Leasehold land. The reaction from the United Graziers' Association was first one of outrage that a government would dare to use satellite imagery to monitor land clearing. Reaction then changed to a more conciliatory attitude based on 'lack of consultation' (P.M. 22 March 1995).

The Federal Opposition released a Discussion Paper, "A Clean Australia", in January 1995 in which there was a proposal for an Australia- wide voluntary cessation of broadscale tree clearing. It also included an ambitious program of revegetation to assist with both land degradation and greenhouse emission problems.

The Federal Government apparently supports these proposals to some degree as the Government's 'Greenhouse 21C' package (March 1995) also included revegetation as a strategy for handling both of these environmental problems. It included expanding the One Billion Trees Program and the development of a joint Commonwealth/State project to develop a better database on land clearing in Australia.

Strategies For Achieving ESD In Dryland Farming

Previous sections have dealt with policies and programs that encourage better farm business practices and, to a lesser degree, the adoption of conservation farming practices. However for ESD principles to be realised in a reasonable time frame there is going to have to be far more emphasis on the latter.

It has been argued for many years now that retention or planting of trees and shrubs in the landscape should be beneficial in controlling groundwater recharge. Additional benefits cited also include the provision of longterm timber crops, drought fodder reserves, windbreaks, wildlife corridors and insect pest control through the provision of refuges for birdlife. In more recent times, the importance of vegetation in the control of 'greenhouse' gases (principally carbon dioxide) has been brought to the attention of the public (National Greenhouse Gas Inventory Committee, 1994). Hence it would seem sensible to examine an active on- farm revegetation program as a vehicle for achieving ESD principles.

Avenues for change

Mobbs (1994), in preparing a discussion paper for consideration by the National Farmers' Federation, made the interesting observation that governments have already developed a number of strategies in response to ESD goals. These include:

National Water Quality Management Strategy

Draft National Strategy for the Conservation of Australia's Biodiversity

National Forest Policy Statement

National Regional Development Strategy

National Greenhouse Response Strategy.

However they have not yet considered a similar strategy for the development of agricultural land.

A similar approach is already being used in the development of Land and Water Management Plans within a number of catchments and regions. Cynics would suggest that such plans are yet another exercise in support of an ever expanding government bureaucracy, but the exercise is having the effect of creating dialogue between landholders and government agencies. At the moment, however, that dialogue is largely restricted to the 'dedicated few' within the farming community.

With recent drought and rural adjustment legislation the mechanism now exists to allow governments to enter into individual contracts with landholders. Already there is an implied demand for better management associated with government assistance, and some forms of tax relief are associated with the possession of a Property Management Plan. There is no reason why governments should not become pro- active and offer assistance in the implementation of environmentally sound agricultural systems rather than the present approach which is implemented more as a system of 'last- resort'. Actively supporting a landuse system such as alley farming need in no way infringe the farmers' rights to change from enterprise to enterprise - in fact it would probably provide a greater freedom to do so. Hence the greatest fear expressed by farmers, viz., 'government regulation', would be avoided whilst at the same time profitability should improve considerably.

Regardless of the 'fear of regulation' aspect, such a system would require a major change in attitude by both the farming community and by governments. For too long both parties have been avoiding change by making excuses about having imported inappropriate European farming techniques at the time of land settlement. Whilst there is a certain amount of truth in that argument one must wonder why it has taken 200 years to come to that conclusion!

Financial constraints on the part of landholders are undoubtedly a major factor in implementing change. An analysis ( ABARE 1995) has shown that 70 percent of broad- acre agricultural production originates from 30 percent of farms. This means that there are probably 70,000 or so properties where the landholder is either just making a living or is in a negative economic balance. Such a situation is not conducive to large scale changes in the dryland agricultural industry.

It is also a relatively rare situation for all agricultural enterprises to be in a healthy state at the one time, so we can assume that financial constraints apply at frequent intervals to most farmers.

Thus any widespread change in agriculture in the future will almost certainly have to be accompanied by appropriate financial assistance. Governments also have financial constraints and there is a reluctance to spend public money on what they see as 'private gain'. In many ways this is a reasonable attitude as actively investing in one industry would certainly create demands to do the same in other industries. Drought aid and rural adjustment aid already fringe upon an artificial support system. Having provided the legislative mechanism by which dryland agriculture could be rationalised, the Commonwealth and State Governments appear reluctant to 'make it work'. The preferred option still appears to be one of 'last resort' rather than a normal part of government - producer interaction.

It is not all that long ago that the dairy industry underwent a massive restructuring program and now it is one of the most profitable agricultural enterprises available. However that was a small exercise as compared with reform of dryland agriculture in general, should the latter ever reach the same sort of crisis point.

At the moment approximately $1 billion of public money is expended annually on natural resource management. Governments actively promote this type of expenditure as being 'Landcare' but only a minute proportion ever finds its way to on- farm restoration projects. Even the $5- 6 million allocated from the National Landcare Program to Landcare groups in 1993- 94 was largely spent on public lands or on small, on- farm demonstration sites (Williams, 1995a). There is of course nothing wrong with improving public lands but one would expect at least equivalent concern for productive land.

Making a change

Change in dryland agricultural practices is already taking place under the influence of agricultural and technological research and development funded by governments and industry. All are providing incremental improvements to the ways in which farmers manage their land and water resources. However it is questionable whether the rate of change is sufficiently rapid or well enough targeted to:

rescue those 70 to 80 percent of dryland farm enterprises that are only marginally viable

halt the continuing environmental damage that is occurring year after year.

Although governments have not yet developed a national policy directed specifically at the agricultural industry the Agriculture and Resource Management Council of Australia and New Zealand has been developing a policy framework for development in rural areas (ARMCANZ, 1994). Although directed specifically at the 80 per cent of the rural population that does not make its living from agricultural pursuits the policy framework contains statements that are also directly applicable to dryland farmers. For example,

the package of policy measures in place, while sound in philosophy, is currently limited to helping a relatively small number of producers and community groups and,

the present policy framework is yet to encompass an overall vision of rural communities and rural development that would enable a systematic national approach to resolving these key issues

Kerin (1995) added further to the uncertainty surrounding attitudes to agriculture by arguing,

As long as farmers are not subsidised, I see no other approach to sustainability of agriculture other than continued investment in all forms of research and the iterative adoption of such research

He continued,

We can also learn that change will not come about if farmers control policy or if governments alone decide what policies are to be put into effect. This is why mechanisms such as Landcare, if constantly thought through, have a better chance of directing this generation's farmers towards sustainability and to leave a decent legacy for future generations.

Thus in making a change it would appear that a number of the key points are:

present subsidy schemes simply encourage an incremental adoption of improved land management practices rather than a holistic approach

relatively few farmers receive the type of assistance that would enable them to implement a number of improved land management systems

change will only occur if farmers and governments together decide on future policies

there is a lack of a vision for the future with respect to agriculture.

This paper does not support the present incremental approach on the grounds that there is no evidence that land degradation in dryland agricultural areas and resultant environmental damage is being controlled to an acceptable level. It is simply not sufficient to keep expanding research and development and education programs in the hope that farmers will put that information into practice. The paper has also attempted to provide a vision, based on an agroforestry system, for the revegetation of farmlands in order to make them more productive while at the same time providing longterm protection for the environment. It may not be the only environmentally sound approach to dryland farming but it does have national application. Other systems should be considered according to the environmental hazards discussed earlier. In particular the question of groundwater recharge control should be an essential aspect of any proposal as waterlogging and salinity are now a major threat to dryland agriculture, not just irrigated areas.

The question of joint farmer and government consultation on ecologically sustainable development has not yet taken place on a national scale. The infrastructure to permit this to happen is largely in place with the system of Total Catchment Management or its equivalent being adopted in all states. However at the moment there are considerable problems with that regional- type structure as in many instances TCM committees are functioning by the enthusiasm of a dedicated few rather than the farming community as a whole. It is in danger of becoming regarded as simply another level of bureaucracy rather than as a unifying force that will produce realistic goals and actions in the future.

Regardless of what forum is devised for obtaining consensus between farmers and governments, the latter through their commitment to ESD have a mandate and a duty to pursue its principles in a timely and effective manner on behalf of all Australians.

The form of assistance would also be subject to agreement between governments and individual landholders. Present tax concessions for on- farm land and water conservation works and equipment mean very little to the majority of farmers. Longterm low interest loans for specific on- farm works may be more attractive to those who would like to implement ecologically sound farming systems but who dont have the cash to make a start.

Governments presently spend about $1 billion annually on natural resource management - a large proportion of which is allocated to supporting staff. It would seem then that there is a financial capacity to invest in productive lands - especially if it were to achieve the major policy objective of ESD. Using the target figure of $10 billion as the most expensive option would mean an outlay of $500 million /year over the next 2 decades or so. However providing initial seed loan money to modify ten per cent of each property might well be sufficiently successful for the farmers to continue the process through their own resources.

The expenditure would largely be in the form of loans for materials (fencing, planting stock, herbicides etc) and for assistance with labour through one of a number of the LEAP and REEP- type employment schemes It would also assist in treating those parts of each farm that are most susceptible to land degradation and which presumably are presently contributing most to environmental damage. That is, the government action would be seen to be very clearly targeted and proactive rather than the present diffuse and poorly timed approach.

Those landholders who have difficulty with the idea might be persuaded otherwise, over a period of time, either by the example of their peers or by a withdrawal of existing, unattached 'support' schemes.

Finally, if governments themselves are overwhelmed by the magnitude of the vision, then it would always be possible to compromise by setting up demonstration areas. However any demonstration area less than a substantial total catchment ( thousands of hectares in magnitude) would be counter- productive. There would be no need for lengthy decision making processes as the geoclimatic zones and vegetation densities required are already well known and representative sites should be relatively easy to define. In fact, the Land and Water Resources Research and Development Corporation (LWRRDC) together with the Murray Darling Basin Commission (MDBC) and the Australian Bureau of Resource Economics (ABARE) are presently supporting dryland salinity research in 5 'focus' catchments located in Queensland, NSW, Victoria, SA and WA (Webb, 1994). These might well contain rural populations amenable to a vision of this nature.

There is nothing more certain than that the productive resource base of this country will continue to decline unless governments become pro- active in protecting agricultural lands.

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