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Recognise Relate Innovate
by Christine Jones
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INTRODUCTION The vitality of all the living things above ground, the grasses, flowers, crops, pastures, trees, shrubs, animals, birds, and last but not least, the people, reflect the dynamics of the soil below. Soil microbes and tiny soil animals, almost too small to see, form the base of the pyramid of life. Vibrant soils give rise to a diverse, flourishing ecosystem. Lifeless soils give rise to …… nothing much at all. By carefully observing what happens around us, we can tell how things are going in the engine room. We each possess the inherent wisdom and skills to manage our land. Take a walk through your paddocks. What do you see? What do you smell? What do you feel? Perhaps we need to re-visit our L’s? Look. Listen. Learn. Conventional agriculture has got us to where we are now. More of the same can only make things worse. Often we don’t notice little changes, but over time, the cumulative impacts can be devastating. The insidious ‘sleeping giants’ of soil structural decline, acidity, sodicity and salinity, and most significantly, the depleted nutritional value of our food, are all symptoms of inappropriate soil management. For the past 200 years of European settlement we’ve largely ignored the long-term consequences of our actions. When we RECOGNISE that the quality of our day to day lives is directly influenced by the quality of life in the soil ……. ……. when we can RELATE on a personal level to a world that is hidden from our view, but paradoxically always under our feet ……. ……. then, and only then, can we truly INNOVATE. Isn’t it time we started to really look after the workers in our soils? Make the restoration of life in the soil our top priority? From this, all else will flow. All are connected. Australian agriculture is at the crossroads. Will you continue with business as usual? Or take a new path ……. ? Recognise ……….. Relate ……... Innovate …….. GETTING THE BASICS RIGHT "The nation that destroys its soil destroys itself" (Roosevelt 1937) Biologically active, self-renewing topsoil is the cornerstone for a productive agricultural sector and a robust environment. It is essential for the health of plants, animals and people. The appropriate management of soil biology in agricultural, horticultural, forestry, amenity, wildlife and conservation areas is the most vital, and most neglected, of the natural resource issues facing Australia. Most of our grasslands and croplands aren't as healthy as we’d like them to be. They are often characterised by areas of bare ground, sheet and gully erosion, the presence of weeds and the lack of desirable plant species. It is easy to assume that removing the weeds and replanting some 'better' species will solve the problems. Decades of experience have demonstrated that the simplistic approach rarely works. The interactions between animals, plants and soil biota remain out of balance because the over-riding importance of soil management has not been addressed. The resulting shortfalls in ecosystem services, such as nutrient availability, need to be supplemented at our own expense. Landscapes are not degraded because they lack desirable species. Rather, desirable species will not flourish when landscapes are degraded. In the agricultural context, grazing and cropping account for the major portion of the land area. If the primary focus of natural resource management is to be the maintenance of high levels of humic materials to rebuild topsoil, then radical departures from conventional methods of production will be required. REGENERATIVE LAND MANAGEMENT Agricultural practices can be productive, profitable and restorative provided they: i) regenerate, rather than merely 'sustain', the natural resource base ii) enhance, rather than replace, natural ecosystem processes iii) stimulate the formation, rather than attempt to reduce the loss, of topsoil. Regenerative vs sustainable agriculture
Many of what are termed ‘sustainable’ agricultural practices represent only small improvements in current methodology. At best, they impart a fleeting tinge of green to a deteriorating landscape. ‘Regenerative’ practices embody fundamental redesign (Hill 1998). They utilise natural ecological services to replenish and reactivate the resource base. When agriculture is regenerative, soils, water, vegetation and productivity continually improve rather than staying the same or slowly getting worse. Regenerative agriculture is productive and profitable. It instills a deep sense of personal satisfaction in farmers, rural communities and observers. Revitalising the natural resource base rekindles our sense of self and our sense of place in the environment. Enhancement vs replacement philosophy
The traditional approach to land management has been one of 'simplistic replacement' (with exotic species and unbalanced chemical fertilisers) rather than a multi-level, multi-species approach. In recent times, there have been concerted attempts to make oversimplified ecosystems 'sustainable'. It is a battle which cannot be won. Until a preventative rather than a curative approach to land management is adopted, agricultural ‘problems’ such as soil compaction, low fertility, weeds, pests and diseases, and their ‘treatments’, will continue indefinitely. The more components in an ecosystem, the greater the synergy between the parts. To improve the diversity and health of agricultural landscapes, we need to think creatively and MANAGE for change, rather than embarking on the broadscale replacement of natural biological processes with expensive technology. It is difficult to step off the replacement treadmill, because nutrient acquisition and distribution no longer occur naturally in dysfunctional soils. However, the costs of production continue to increase for as long as the replacement philosophy endures. Soil formation vs soil lossThe true bottom line for any agricultural practice, is whether soil is being formed or lost. If it is being lost, farming will eventually become both ecologically and economically impossible. Organic matter and associated soil microbes are necessary for soil aggregation and the formation of tiny spaces, or pores, which hold water and increase the storage capacity of the soil (Donahue et al. 1983; Killham 1994). Organic matter is also the soil component with the greatest affinity for water (Faulkner 1945). Reductions in the organic matter content, absorbency and water-holding capacity of Australian soils became evident within a few years of areas first being settled for agriculture (Robertson 1853; Bean 1916; Martin 2001a,b) and have continued as agricultural practices have intensified (Charman and Roper 2000). These changes have resulted in nutrient deficiencies in soils, plants, animals and you and I, the consumers of agricultural produce. Loss of soil integrity has also led to the increased transport and accumulation of sediment and salts. Regenerative agriculture is not possible without actively forming topsoil and new topsoil cannot form unless there are high levels of biological activity. Once we recognise the significance of this relationship, and focus on its achievement, agriculture becomes less complicated and far more rewarding. WATER IN THE LANDSCAPE The health of terrestrial and riverine ecosystems are intrinsically linked. Rivers and streams exist only because of the catchments that feed them, and cannot be regarded as separate entities to those catchments. The management of sediment, nutrients and other water pollutants is extremely difficult when we attempt to deal with them only along the streambank, the narrow interface between the land and the water's edge. Problems are magnified by the fact that most pollutants enter streams and rivers as point source flows via channels of various forms, including natural and man-made drainage lines, eroded gullies, vehicle tracks and animal pathways, rather than diffusing through a riparian filter as is often imagined. In a whole of landscape regenerative approach to water quality and river health, the emphasis is on the management of the entire catchment as a riparian buffer zone. Paradoxically, the healthy functioning of the 'whole' requires land management at the scale of the raindrop. After a raindrop hits the ground, one of four things happen. It can: i) go UP, as evaporation or transpiration
The tell-tale signs of poor catchment health. A trickle of algal slime winds through a bed of sand, covering what was once a rocky base with deep fishing holes and clear, fresh water. The length of time that water is HELD in soil is the factor in the water balance equation that has changed the most since European settlement. We have become so familiar with dysfunctional soils of low water-holding capacity that we tend to overlook this extraordinarily important point. More water moves SIDEWAYS than it should. Moving water is accompanied by soil particles, surface organic matter, soluble nutrients and animal dung. The loss of these components from the terrestrial environment reduces productivity, while their addition to the riverine environment reduces water quality. This LOSE-LOSE situation can be converted to WIN-WIN by placing more emphasis on holding water where it falls and controlling its subsequent movement. Fortunately land management techniques which improve soil surface condition, porosity, aggregate stability, infiltration rates, soil water holding capacity and the quality of groundcover are being more widely recognised and adopted. These management regimes not only confer production advantages to landholders, but also ensure that water passes through a series of biological filters on its journey to rivers and streams. As a bonus, high infiltration rates in the upper parts of catchments replenish transmissive fresh water aquifers and produce perennial, moderated baseflow to streams. If groundcover is poor and soil water holding capacity is low, rapid run-off leads to boom-bust streamflow, resulting in water-logging and frequent flooding in lower landscape positions in wet years and inadequate streamflow in dry years.
Participants at the Landcare/Rivercare ‘Beyond Streambank Fencing Forum’ held in Gloucester, NSW, listen to pearls of wisdom from Col Freeman and Rick James DRYLAND SALINITY IN PERSPECTIVE Areas currently experiencing salinisation in south-eastern, southern and south-western Australia were mostly grasslands and grassy woodlands at the time of European settlement, as recorded in explorers journals, settlers diaries and original survey reports from the early to mid 1800s. It is intriguing therefore, that tree clearing in the early 1900s, or later, continues to be cited as the ‘cause’ of dryland salinity. There is no doubt that the removal of any kind of perennial vegetation will have an effect on water balance. However, to insist that dryland salinity is the result of tree clearing is a misrepresentation of the facts, particularly when twisted in the current form "if we put the trees back, we can solve the problem." Some parts of Australia did not have any trees at the time of settlement. In some regions trees and shrubs have become woody weeds, in others the environment would be healthier today with more trees. However, these issues have very little to do with dryland salinity. We need to address the lack or perenniality across the entire landscape, not just in parts of it, and not just with one type of vegetation. Woody vegetation, or crops such as lucerne, can pump accumulated groundwater. This represents a biological form of an engineering solution and treats symptoms not causes. In order to move forward and find some real solutions to the salinity crisis, it is important to view the ‘transient tree phase’ in perspective. It is the overlooked understorey, or more particularly, the groundcover and soils, which have undergone the most dramatic changes since settlement. The real cause of dryland salinity is reduced levels of biological activity in soils, leading to the loss of soil integrity and soil water holding capacity (Jones 2000b, 2002c, 2001a).
Dr Wal Whalley discusses the process of salinisation with a double Helix Science Club group at a dryland salinity site at Wollun, northern NSW. BURNING The available evidence from the charcoal record indicates that the frequency of burning in Australia (including wildfires) increased shortly after European settlement. In summary, it seems that some indigenous people in some places burnt some of the time, but that not all indigenous people everywhere burnt all of the time, as is commonly assumed (Mooney et al., G. Martin, pers. com.). After European settlement, the regular burning of rank herbage (symptomatic of selective grazing) at the end of winter to encourage 'green pick' in spring, became a common practice in many areas. Regular burning is extremely detrimental to soft forms of native groundcover. It encourages a dominance of fire tolerant, relatively unpalatable, warm-season perennial grasses such as blady grass (Imperata cylindrica), bunch spear grass (Heteropogon contortus), African love grass (Eragrostis curvula) and Coolatai grass (Hyparrhenia hirta). These are often the very species it is hoped that burning will reduce. Hot burns remove surface litter, leaving the soil unprotected. The loss of organic matter in turn reduces the level of soil biological activity, nutrient cycling, nutrient availability, soil porosity, soil water-holding capacity and soil structure. Reduced rates of infiltration are reflected in increased rates of runoff, accompanied by the movement of sediment, surface organic matter and animal dung to waterways. Although burning may produce palatable regrowth in the short term, it dramatically reduces the quality of groundcover over the longer term. The native species which are the most nutritious from an animal production perspective (including perennial native legumes and cool-season native grasses) are not tolerant of a combination of burning and grazing. The recruitment of productive native legumes and grasses is favoured by a mulched soil surface, which is destroyed by regular burning. The use of fire for the removal of excess growth may appear attractive, but results in atmospheric pollution, the loss of many nutrients which would be recycled in the grazing process, loss of surface litter, and, if used frequently, bare ground. Landholders may have valid reasons to use fire, such as woody weed control, or the enhancement of fire-dependent species. However, in view of the risks, fire is a tool which should be used cautiously and infrequently. SMALL NATIVE MAMMALS The open, park-like appearance of many areas at the time of European settlement has often been attributed to indigenous burning regimes. More recent evidence suggests that the healthy grasslands and friable soils described by the first settlers were more likely to have reflected the high abundance of small native mammals, such as bettongs and potoroos (Martin 2001 a,b), most of which are now locally extinct. These nocturnal, rabbit-sized animals were ground-foragers and browsers rather than grazers. Their principal food sources were fungi, underground tubers, tree and shrub seedlings, seeds, berries and insects (Cronin 1991). During the foraging process they incorporated surface mulch, reducing fuel loads and fire intensities, as well as improving soil health, assisting in soil formation, spreading and nurturing beneficial soil organisms and providing a favourable seed-bed for the germination of native grasses and forbs. As well as enhancing soil biological processes small native mammals played a pivotal role in the landscape by maintaining a balance between woody vegetation and groundcover plants (Martin 2001 a,b). The benefits to ecosystem health were not appreciated and potoroos and bettongs, in particular, were regarded as pests. Bounty systems operated in many regions and widescale poisoning was commonplace. The omnivorous small native mammals were replaced by herbivores such as kangaroos (which increased in abundance after European settlement), sheep, cattle, goats, horses and rabbits. Unmanaged grazing by these animals severely damaged the groundcover in many regions, further upsetting the balance between trees, shrubs and grasses. GRAZING MANAGEMENT FOR HEALTHY SOILS Managed grazing is the management of the relationship between animals, plants and the soil. With the loss of the regenerative effects of small native mammals in Australia since European settlement, managed grazing is now arguably the only natural means by which grasslands can be 'improved' in a holistic way. To enhance both animal production and the functioning of ecosystem processes, the aim of strategic grazing should be to stimulate new growth, encourage the germination and establishment of new plants, feed soil organisms by transferring photosynthate from above ground (leaves) to below ground (roots) and pruning these roots into soil (Jones 2000a). The desired outcome is a variety of groundcover plants of different growth forms (grasses and non-grasses), a diversity of plant ages, well mulched soils, high levels of soil biological and microbiological activity and evidence of new topsoil formation. Grasslands have evolved over millions of years with various forms of intermittent disturbance which facilitate energy flow and the recycling of nutrients. In medium to low rainfall areas, grasses which are not grazed or do not have above-ground parts returned to the soil in some other way, become senescent and cease to grow productively (McNaughton 1976, 1979). If all animals are excluded, the health of the grassland declines over time (McNaughton 1976, Savory 1988). Graze periodsWhen livestock are left in the same paddock for long periods of time they place continual grazing pressure on the most palatable grasses and these are kept short. The compromised root system of these overgrazed plants renders them extremely vulnerable during droughts (Jones 2000a). Productive native perennial grasses and perennial native legumes such as Lotus, Hardenbergia, Glycine and Desmodium spp. tend to be more sensitive to continuous grazing than are most introduced plants. The majority of the highly palatable native species rapidly disappear under continuous grazing. Conversely, their abundance can increase under appropriate high-density short duration grazing (Earl and Jones 1996, Earl 1998). To achieve healthy grasslands in medium to low rainfall areas, it is recommended that stock be bunched into large mobs and moved frequently. The availability of low cost electric fencing makes grazing ‘cells’ an economical and convenient tool for stock control. Construction costs can be minimised initially with the use of moveable electric tape and moveable water troughs. In extensive areas with few fences, stock can be herded, as is now the practice on many large tracts of public land in the United States and Canada.
An electric wire at nose height contains cattle in a grazing ‘cell’, on Scott and Dan Macansh’s property “Deepwater Station”, Deepwater, NSW. During the graze period (which is most commonly one, two or three days), a useful guide is to aim for approximately 20% of the available forage to be trampled to form surface litter and approximately 20% to be left standing (ie. no more than 60% utilised for animal consumption). The percentages vary with circumstances but the importance of forming surface litter cannot be overemphasised. Stock densities are generally most effective for plant and soil regeneration if they are 200 dse/ha 1 or higher.
Ultra short and short duration grazing (with rest periods as outlined below) are highly recommended for all grassy woodland vegetation, to increase groundcover, diversity, plant vigour and levels of soil biological activity. The quality of groundcover deteriorates when plants are exposed to long graze periods. Medium, long and very long graze periods are not recommended for any type of vegetation. Rest periodsAll groundcover benefits from relatively long rest periods between graze periods. This helps plants develop deep root systems. If desirable grasses are rested from continuous grazing and then defoliated in a single grazing event (such as in cell, planned, or pulsed grazing), a large proportion of roots cease respiring and die within a few hours of the removal of the leaves, in order to equalise the biomass (Jones 2000). The root pruning effect is regenerative rather than degenerative. These 'pruned roots' provide extremely valuable organic matter which improves the physical, chemical and biological attributes of the soil. Leaf regrowth can begin within hours of grazing, provided soil moisture and temperature conditions are favourable and plant roots have not been stressed by previous set-stocking. Allowing stock to remain on pastures during early regrowth stages will severely deplete plant energy reserves, resulting in the formation of a steady-state type of equilibrium, where both tops and roots remain restricted in size, such as is found in mown turf and continuously grazed grassland (McNaughton 1979, Richards 1993). Grasslands should not be re-grazed until the plants which were most heavily grazed on the previous occasion are fully recovered (Savory 1988). Immediately prior to re-grazing, the palatable species should appear as though they have NOT been grazed. Only then is it regenerative, rather than degenerative, to graze them again. This may take from 3 to 12 months, depending on environmental factors. A failure of plant recovery during the resting phase is indicative of ineffective soil biology. The most common 'problem' is a dysfunctional nutrient cycle due to low levels of microbial activity. Stimulation of the nutrient cycle is best achieved through intermittent root pruning (Jones 2000) and mulching the soil surface using high-density stocking to trample a greater percentage of the biomass than is grazed. During the transitional phase (ie when grazing management is first changed and soils are still dysfunctional) biological preparations which stimulate soil microbial activity can prove useful. Integrating graze and rest periodsIt is recommended that high-density short duration graze periods (generally shorter than 3 days) be followed by long recovery periods (generally longer than 90 days). High stock densities and short graze periods are preferable to longer graze periods at low stock densities. These graze and rest periods are recommended for grassland plants which are considered desirable from an animal production perspective. Grazing the most palatable plants intermittently with relatively long rest periods between graze periods, increases their productivity by building strong root systems. Competition below ground prevents relatively unpalatable plants from dominating the pasture (Jones 2000). It is also important that desirable forage components not be overrested. Senescent plants are relatively nutrient poor and have low digestibility. In addition, they can inhibit the growth of other grassland species such as native herbs which may contribute significantly to both biodiversity and livestock production. Not all pasture components need to be grazed. Up to 30% of relatively unpalatable, ungrazed tussocky plants can improve the structure and function of grasslands and provide similar benefits to scattered trees. Tussocks often represent islands of fertility. They can increase soil biological activity, improve soil moisture conditions, maintain humidity at ground level, reduce wind-speed, provide shelter for newborn lambs and calves and habitat for reptiles and ground-feeding birds. The result is better ecosystem function than occurs in short, uniform pastures. When grazing management is attuned to plant requirements, more feed can be produced and carrying capacities generally improve. However, stocking rates must not be increased before a feed surplus occurs and must be reduced immediately if pasture biomass levels fall. Changes to conventional grazing practices which foster net gains in the diversity and vigour of groundcover will enable a greater range of ecological and production goals to be satisfied than are currently possible in most situations. Of particular importance from a rangeland health perspective, is the effect of appropriate grazing management on the infiltration of rainfall and the water-use efficiency of plants, drought survival, biodiversity, soil organic matter levels, the acquisition, storage and cycling of nutrients, soil structural stability and buffering capacity. These factors are the drivers for landscape function, soil formation, farm productivity and water balance. Improvements in these factors can restore hydrological balance on a catchment scale and most importantly, strengthen rural communities through their impact on farm profitability. CROPPING INTO PERENNIAL GROUNDCOVER Annual crops and pastures characterise many of our agricultural landscapes, resulting in bare ground for much of the year, every year. In the absence of a protective mantle of plants and plant litter, soil quickly becomes a biological desert. Low levels of microbial activity lead to greater reliance on harsh chemical inputs, greater production risks, increased susceptibility to soil pathogens, mineral imbalance, structural decline, erosion, sodicity, acidity and dryland salinity. These 'problems' do not exist in isolation and should not be treated in isolation. Most would not need to be treated at all if healthy perennial groundcover was restored to agricultural soils. There is no need for cropping enterprises to cease. All that is required is a change in approach. The techniques of Pasture Cropping (Cluff and Seis 1997; Jones 1999) and Advance Sowing (Maynard 2003), for example, involve direct drilling cool season grain or forage crops, or warm season forage crops, into pre-existing groundcover, without the need for soil inversion or repeated herbicide applications. These techniques enhance soil structure, biological activity, nutrient cycling and disease suppression and foster healthy crops. Initially, compatible groundcover may need to be undersown in areas with a long farming history, to form a perennial base for cropping in future years. Warm season native grasses such as redgrass (Bothriochloa macra) or bluegrass (Dicanthium sericeum) provide an ideal complement to winter crops. Introduced species such as purple pigeon grass (Setaria incrassata), bambatsi panic (Panicum coloratum) or premier digit grass (Digitaria eriantha) might also be suitable, provided they did not compete with the crop. The perennial groundcover would need to be completely rested from grazing in the first summer after establishment but could be cropped in the following year and strategically grazed in subsequent summers. It would provide valuable extra feed as well as soil cover during a time when paddocks would otherwise be bare. Despite the adoption of ‘sustainable’ cropping practices such as stubble retention and minimum tillage in Australia, we continue to lose an average 7 kg of soil for every kilo of wheat produced (Flannery 1994). It isn’t good enough. The breakthrough with perennial groundcover farming techniques is that they are able to improve the vigour and diversity of the grassland AND improve the condition of the soil, as well as produce grain crops in favourable years. This is not possible with any other cropping method. The restoration of perennial groundcover over the large tracts of land which are currently farmed has enormous potential to reverse dryland salinity, through improvements in soil structure and water-holding capacity.
INTRINSIC VALUES OF NATIVE GROUNDCOVER Groundcover is the herbaceous component (grasses and forbs) of grassy woodlands, shrublands and grasslands. Prior to European settlement the seeds of many native grasses, the roots of grassland species such as yam daisy (Microseris lanceolata) and the tubers of lilies and terrestrial orchids, provided a staple carbohydrate source of fundamental significance to Aboriginal people. Livestock production based on native groundcover provided the main source of income for the majority of Australia's first white settlers. Due to grazing regimes which were unsuited to Australian conditions, the abundance of many groundcover species declined from being common and widespread, to rare or locally extinct, within only a few years of settlement. The food plants most keenly sought by livestock were also the most highly valued by the Aboriginal people. The significance of the rapid loss of many of these important components of the Aboriginal diet, to Aboriginal people, has been largely overlooked. Native grassland ecosystems are now among our most threatened plant communities. Their demise is of ecological, cultural and economic significance. Most of the 'remnants' are in relatively inaccessible areas or on poorer soils, and are often of low quality. Generally only the least palatable components have survived in continuously grazed pastures. Many of the areas that were the most productive originally are now the most depleted, particularly with respect to soil structural stability and biological health. There are many misconceptions surrounding the value of native groundcover and the type of management required to improve the natural fertility of soils. Perennial native grasses such as Common Wheat Grass (Elymus scaber) and Microlaena (Microlaena stipoides) and perennial native legumes such as Lotus, Hardenbergia, Glycine and Desmodium are often of higher quality and more drought tolerant than introduced perennial grasses and legumes (Jones 1996). Unfortunately, some of the most productive native pasture plants are also the most sensitive to inappropriate grazing regimes. When managed in a regenerative way, diverse native groundcover plays an important role in soil conservation and ecosystem function as well as a valuable economic role in animal production. INDICATORS FOR THE HEALTH OF GROUNDCOVER "The real voyage of discovery consists not in seeking new landscapes but in having new eyes" (Marcel Proust: 1853-1922) Diverse, vigorous groundcover contributes to active soil formation, an effective water cycle and perennial streamflow. It provides livestock with a good balance of protein and energy throughout the year as well as improving the habitat for soil organisms and the many small animals that are essential for free ecosystem services on farms. What does healthy groundcover look like?
MONITORING It is important to regularly monitor groundcover and soils to determine your progress and to adjust the grazing regime, or other land management techniques, as required. The monitoring should include measurements of the soil surface condition, percentage canopy cover, plant basal cover, litter cover, botanical composition, seasonal productivity, vigour and age structure of the groundcover. The Holistic Management Biological Monitoring technique is recommended as a relatively simple yet comprehensive natural resource audit of these factors. As such, it provides an early warning indicator of the response of groundcover to management strategies, as well as providing an indication of the effectiveness of nutrient cycling, photosynthetic capacity and plant community dynamics (Savory and Butterfield 1999).
Mary and Richard Maclean, Lorne and Geoff Siems, Lyn Gill and Ian McLelland, prepare to monitor groundcover on “Woodville East” near Armidale, NSW. Red and green flagsListed below are some 'green flags' (good signs). The opposite to each of these is a 'red flag' (danger signal). You will know you're making progress when:
SOIL BIOLOGY AND PLANT NUTRITION Australian soils are generally old and deeply weathered (White 1994, Murphy 2000). As a result there are many active adsorption sites on soil particles on which plant nutrients can become 'fixed' unless they are protected within the soil food web of living organisms (Hill 1989). Due to management regimes which inadvertently destroyed this soil food web, most agricultural soils are now very low in biological activity. Although there may be reasonable levels of minerals, most of these will not be available to plants. For example, total phosphorus levels are quite high in many soils, but around 99% of it is usually fixed, leaving only 1% available (Stevens 1997). It is the available level which is generally given in soil tests results. Furthermore, 80-90% of the phosphorus applied as fertiliser to soils low in microbial activity is also rapidly fixed (Stevens 1997). The phosphorus bank can only be accessed if soil microbial levels are increased. Fortunately, the age of soil minerals is relatively unimportant to plant nutrition if the topsoil is biologically active (Faulkner 1945, Soule and Piper 1992). The most important ingredients for healthy soils are plant roots, plant litter, high levels of groundcover and an intermittent or patchy disturbance regime (Jones 2001, Martin 2001a,b). In addition to providing substrate for soil biota in the form of organic matter, plants and their roots exude substances which stimulate microbial activity (Killham 1994), particularly in response to grazing (Hamilton and Frank 2001). Microbes in turn produce vitamins, plant growth hormones and enzymes which encourage strong root growth and increase the availability of nutrients (Donahue et al. 1983, Hill 1989). Many species of bacteria and fungi can access nutrients such as nitrogen and sulphur from the soil atmosphere, while others facilitate plant uptake of phosphorus, nitrogen and trace elements such as zinc, copper and molybdenum (Donahue et al. 1983, Soule and Piper 1992, Killham 1994, Jordon 1998). Microbes also produce mucilaginous material which helps the soil particles to aggregate, increasing pore size and improving aeration, soil structure and water-holding capacity (Donahue et al. 1983, Killham 1994, Bushby 2001). It is living things that maintain the world around us, the air we breathe, the food we eat and the quality of our vegetation and soils. Furthermore, there must be interactions between living things such as animals, plants and soil biota, and the minerals in soil, in order for nutrients to be cycled, plant growth to be vigorous and for new topsoil to form. These interactions need to be in an appropriate manner and at an appropriate level. The habitat and food sources for soil organisms are reduced by practices such as continuous grazing, regular burning, unbalanced chemical applications and broadacre cultivation. These practices result in soils with low levels of humic materials, low porosity and a reduced ability to hold air or moisture. The legacy of the loss of soil life is that much of our agricultural land today is characterised by compacted, residual mineral soils, which support only low vitality crops and pastures. The key soil management question is therefore "what can we do to provide soil organisms with optimal conditions to get on with their jobs?" (Hill 1989). BUILDING NEW TOPSOIL The most meaningful indicator for the health of the land, and the long-term wealth of a nation, is whether soil is being formed or lost. The future for Australia depends on the future of our soil. If soil is being lost, so too is the economic and ecological foundation on which production and conservation are based. In little over 200 years of European land-use in Australia, more than 70 percent of land has become seriously degraded (Flannery 1994). Despite our efforts to implement 'best practice' in soil conservation, the situation continues to deteriorate. Annual soil loss figures for perennial pastures in Tablelands and Slopes regions of NSW generally range from 0.5 to 4 t/ha/yr, depending on slope, soil type, vegetative cover and rainfall (Edwards and Zierholz 2000). These figures probably underestimate the total amount of soil lost. Erosion can occur at much higher rates during intense rainfall events, particularly when groundcover is low. Areas which have been cultivated (whether for pasture establishment or cropping) are more prone to soil structural decline. Under bare fallows in the northern part of NSW, annual erosion losses in the order of 50 to 100 t/ha are common, with losses from individual rainfall events of 300-700 t/ha recorded in some situations (Edwards and Zierholz 2000). If productive soil continues to be lost, debates about the optimum enterprise mix, pasture species, fertiliser rate, percentage of trees, or any other 'detail' over which we seem to argue endlessly, are irrelevant. They amount to re-arranging the deck chairs on the Titanic. Research efforts in the soil science arena have concentrated on reducing the rate of soil loss. The concept of building new topsoil is rarely considered. Putting life back into soilIn order for new soil to form, it must be living. Life in the soil provides the structure for more life, and the formation of more soil. Building new topsoil is much like building a house (Bushby 2002). A good house is one which is comfortable for the occupants. It requires a roof, walls and airy rooms with good plumbing. Soil with poor structure cannot function effectively, even when nutrient and moisture levels are optimal (Bushby 2002). The roof of a healthy soil is the groundcover of plants and plant litter, which buffer temperatures, improve water infiltration and slow down evaporation, so that soil remains moister for longer following rainfall. The building materials for the walls are gums and polysaccharides produced by soil microbes. These sticky substances enable soil minerals to be glued together into little lumps (aggregates) and the aggregates to be glued together into peds. When soil is well aggregated, the spaces (pores) between the aggregates form the rooms in the house. They allow the soil to breathe, as well as absorb moisture quickly when it rains. A healthy topsoil should be about half solid materials and half pore spaces (Brady 1984). Friable, porous topsoils make it easier for plant roots to grow and for small soil invertebrates to move around. Well-structured soils retain the moisture necessary for microbial activity, nutrient cycling and vigorous plant growth and are less prone to erosion. Unfortunately, soil structure is very fragile and soil aggregates are continually being broken down (Bushby 2001). An ongoing supply of energy in the form of carbohydrates from actively growing plant roots and decomposing plant litter is required, so that soil organisms can flourish and produce adequate amounts of the sticky secretions required to maintain the 'house'. Rates of topsoil formationThe rates of soil formation provided in the scientific literature usually refer to the weathering of parent material and the differentiation of soil profiles. These are extremely slow processes, sometimes taking thousands of years. Topsoil formation is different and can occur rapidly under appropriate conditions. To remain healthy, soil requires perennial groundcover and periodic localised disturbances in the top layer, where most biological activity takes place (Savory 1988, Soule and Piper 1992, Killham 1994, Jordon 1998, Martin 2001). The challenge for the regeneration of our soils, whether used for production or conservation, is to find ways to implement optimum levels of disturbance to restore soil building processes. The extent, frequency and timing of these disturbances need to be varied in accordance with the requirements of different plant communities and prevailing climatic and seasonal conditions. Livestock movements based on short pulses of intense grazing followed by adequate recovery can be used as a tool to prune grass roots and feed the soil biota, trample litter, improve soil surface condition, increase biomass and improve biological diversity above and below ground (Savory 1988, Earl and Jones 1996, Jones 2000). In some situations pulse grazing is more effective when combined with 'pasture cropping', a technique in which annual grain or fodder crops are direct-drilled into perennial groundcover (Cluff and Seis 1997, Jones 1999). This one-pass operation disturbs about 20% of the soil surface, creating localised areas of improved aeration, moisture infiltration and mineralisation. The roots of the rapidly growing crop secrete readily available sugars and other compounds that feed microbes in the rhizosphere, stimulating levels of soil biological activity.
Dr Judi Earl discusses the relationship between grazing management and healthy soils on Cam and Lel Banks’ property “Lakeview”, Uralla, NSW. The late P.A. Yeomans, developer of the Keyline system of land management, recognised that the sustainability of the whole farm was dependent on living, vibrant topsoil. The formation of new topsoil using Keyline principles, at rates not previously considered possible, was due to the use of a tillage implement designed to increase soil oxygen and moisture levels, combined with a rest/recovery form of grazing and pasture slashing, to prune grass roots and feed soil biota. Yeomans was able to produce 10 cm of friable black soil within three years, on what was previously bare weathered red shale on his North Richmond farm (Hill 2002). Bennett (1939) calculated a rate of topsoil formation of just over 11 t/ha/yr for soils in which organic material was intermixed into surface layers. In situations where plant root mass is high, rates of topsoil formation of 15-20 t/ha have been indicated (Brady 1984). Healthy groundcover, high root biomass and high levels of associated microbial activity, are fundamental to the success of any technique for building new topsoil. If the land management is appropriate, evidence of new topsoil formation can be seen within 12 months, with quite dramatic effects often observed within three years. Many people have built new topsoil in their vegetable or flower gardens. Some have started to build new topsoil on their farms. If you have not seen new soil being formed, make a point of doing so. Ingredients for soil formationThe material which today is commonly regarded as 'soil' is a residue of rock minerals which are only ONE component of soil. It is through the re-instatement of the missing components that new topsoil is formed. Healthy topsoil is composed of weathered rock minerals, air, water and living things such as plant roots, microorganisms, insects and worms and the organic materials they produce. There are six essential ingredients for soil formation.
There is little information available as to how to increase the levels of air, water and organic materials in soil. For this reason, components 5 and 6 of the soil building checklist tend to be overlooked. That may explain why many people believe that new topsoil cannot be formed. One has to wonder, how did all the topsoil get here in the first place??? We know how quickly we lose it when we ignore the fundamental importance of components 5 and 6. To turn things around, we need to encourage soil building processes EVERY DAY in our land management. Rules of the kitchenFor ALL land, whether for grazing, cropping, horticulture, timber, conservation or recreation. - NO BARE SOIL. Soil must always be COVERED with plants or plant litter. - Produce ORGANIC MATTER. Rest groundcover from grazing, or grow green manure crops with minimum tillage. - GRAZE or slash the groundcover periodically. Use high stock densities for short periods to place organic matter both IN and ON the soil (root pruning and litter trampling). On pasture cropped land, this may include one or two in-crop graze periods. Green manure crops should be lightly incorporated, although animal impact is the preferred option. Set the oven Soil conditions must be such that soil organisms can flourish. High levels of biological activity are required. Think carefully about the effects of any drenches, pesticides, herbicides and fertilisers you may be using. Cooking time The higher the biomass and turnover of plant roots, the faster new topsoil will form. It is the energy from biological activity that drives the process. Monitor progress SMELL: A composty smell indicates high levels of biological activity, particularly fungi. The activities of beneficial soil microbes are important for the formation of soil aggregates which give soil its structure, improve porosity and water-holding capacity. RISING ABILITY: Like a good cake, the soil should rise well and feel light and springy under your feet. Can you easily push a screwdriver in up to the handle? COLOUR: Light, medium or dark chocolate. Can we measure it?You can tell when new topsoil is forming by its composty smell, friable texture and dark colour. Measuring the amount of new soil being formed is a little different to measuring the amount being lost. Mineral soil has a higher bulk density (is more compact) than living soil, and is far more easily eroded. Soil loss figures usually assume an average bulk density (weight per unit volume) of around 1.4 g/cm3 (Edwards and Zierholz 2000). If one millimetre of soil is eroded (about the thickness of a 5-cent coin) that represents about 14 t/ha soil loss. When new topsoil is forming, it will have better structure and will contain more air and more pore spaces than degraded soil, so the bulk density will be less. That is, a given volume of new topsoil will weigh less than an equal volume of non-living mineral soil. The bulk density of new topsoil may be as low as 0.5 g/cm3. In that case a one millimetre increase in soil height would equate to the formation of 5 t/ha of organically enriched topsoil. We currently use the Universal Soil Loss equation (USLE) to estimate soil losses from various agricultural activities. We should perhaps consider developing a Universal Soil FORMATION Equation (USFE) to estimate rates of soil formation. CONCLUSION The building of new topsoil depends on us, and our future depends on building new topsoil. This is the greatest challenge facing modern agriculture. The components which are absent from most of today's soils, that is, high levels of soil organic matter and high levels of microbial activity, are often not as obvious as the symptoms of soil deterioration such as erosion and dryland salinity. Attempts to treat these symptoms with structural works or plantations of trees, shrubs or grasses, can only be partially effective. We cannot alter the type of parent material on which our soils are based. We cannot change property aspect or prevailing climatic conditions. We know we CAN change land management practices in such a way as to rebuild porous, organically rich topsoil. We know we MUST produce new topsoil. WILL we? Professor Stuart Hill (Hill 2002) makes this point abundantly clear:"If we all postpone taking such action, it is certain that the quality of life of future generations will progressively be degraded as we continue to lose our soils, habitats and other species with which we share this amazing planet. I can do it REFERENCES Bean, C.E.W. (1916). 'On the Wool Track'. Hodder and Stoughton Bennett H. H. (1939). Soil Conservation. McGraw-Hill, New York. SPECIAL THANKS A sincere thank you is extended to all who have enthusiastically shared their time, knowledge, wisdom and experience You may see yourself reflected in these pages. I am deeply indebted to Judi Earl, who taught me more about how plants respond to grazing than all the textbooks combined; Col Seis, Darryl Cluff and Bruce Maynard, who have taken the term innovative agriculture to new heights; Greg Martin for explaining the importance of the intermixing of organic matter in the root zone for high levels of biological activity and the formation of new topsoil, and for showing me the small mammals responsible for the soil building processes which took place in Australia prior to European settlement; Allan Savory for his profound insights into landscape processes and the development of the Holistic Decision Making Framework for land managers; Stuart Hill, Patrick Francis, Stan Parsons, Wal Whalley, Matt Cawood, Demetrio Vazquez, Col Freeman, Graeme Hand, Suzie Ward, Jim Manwaring, Margot and Christopher Wright, and Mary and Richard Maclean, for boundless inspiration and support; Matthew and Robert Jones, who have tolerated much absent-mindedness and many absences; Muriel Dell for the artistic cover design for this booklet and infinite patience; and Garry Hickey, for love and light when I needed it most. The administrative and resource support provided by DLWC North Coast Region and the financial assistance granted under NHT Project BD0444.98 'Ecological and Technical Support for Landcare on Rangelands' are gratefully acknowledged.
Hyacinth orchid (Dipodium sp.) is one of the many attractive components of native groundcover. The underground tubers of several species of terrestrial orchids formed a significant part of the diet of Aboriginal people.
The path to regenerative agricultureDespite the volumes of information written on the subject of land degradation over recent decades, our agricultural resource base has continued to deteriorate. The focus for this booklet is a whole of landscape approach to management. The ideas presented evolved from observations and discussions with innovative landholders who were ‘thinking outside the square’ and achieving positive results in terms of improved soils, vegetation and water quality. Their insights were shared with others in a co-learning environment, mostly on-farm. Christine Jones is a grassland ecologist who believes that many of the solutions to seemingly intractable land degradation problems will depend on the restoration and proactive management of perennial native grassland ecosystems, with particular emphasis on the enhancement of root biomass and associated soil biota. Christine has a PhD in Agronomy/Botany from the University of New England and over 30 years’ research experience in the plant sciences. Christine’s articles, including ‘Why the Recharge-Discharge Model is Fundamentally Flawed’, ‘Grazing Management for Healthy Soils’, ‘Cropping Native Pasture and Conserving Biodiversity’ and ‘Building New Topsoil’ have received widespread publicity in print media including The Australian, The LAND, The Australian Farm Journal, Stipa Native Grasses Newsletter, Australian Salinity Action Newsletter, Holistic Management Newsletter, In Practice, New Horizons, Agribusiness Chain, Grassland Matters, Grass Clippings, Landchat, The Australian LANDCARE magazine and GRDC GroundCover. They have also been requested for posting on national and international websites by individuals and groups interested in regenerative approaches to the management of our natural resource base - our future Christine Jones is the recipient of a Land and Water Australia ‘Community Fellowship’ held jointly with Darryl Cluff, Col Seis and Bruce Maynard. The administrative and resource support provided by DLWC North Coast Region and the financial assistance granted under NHT Project BD0444.98 'Ecological and Technical Support for Landcare on Rangelands' are also gratefully acknowledged. Photograph courtesy The LAND newspaper [Peter Austin]
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