Desertification, namely, the formation of desert regions or arid regions of land from vegetated regions of land, is primarily caused by the action of drought and/or by the action of increased populations of humans and animals, particularly, herbivores, inhabiting an area of land.

It is well documented that desertification can be brought about by anthropogenic disturbances of the local habitat. Desertification brought about by anthropogenic disturbances is believed to be responsible for the fringes of the Sahara and Gobi deserts extending further each year. In fact, globally, it has been estimated that a vegetated zone the size of Switzerland is lost each year through desertification caused by anthropogenic disturbances i. e. disturbances of the local habitat caused by the persons and/or their livestock inhabiting it.

The anthropogenic disturbances primarily responsible for desertification are local agricultural practices involving the removal of trees for fuel and timber without replacing them, in combination with over-grazing in such areas by farmed livestock, particularly goats. As will be appreciated, the absence of trees or like structures filtering the strong convective winds caused by temperature differentials in these regions will render the top layer of soil dry and unstable, since the ground water rising at night in such regions will be burnt off by day through the combined action of heat evaporation and wind scorching, leaving behind only mineral particles, which are subject to perpetual drifting. In addition, upward percolation of water will be restricted as a result of the top layer of soil becoming compacted by being trampled on by livestock employed in local agriculture. Therefore, it is evident that desertification results from the combined action of anthropogenic disturbances and the effect of wind action and heat from the sun.

Areas of land, which have been desertified, cannot support anything other than short-term nomadic grazing. In addition, although mineral nutrients are present, the evaporation of water from the upper layers of soil leaves concentrations of salts, which can inhibit the growth of plant life.

Many attempts involving the use of extensive irrigation and desalination schemes have been made to reverse or arrest desertification. Unfortunately, from an economic viewpoint, such schemes have not been considered viable in the light of the costs associated with the extensive requisite irrigation. Others have attempted to reverse desertification by using grasses to"fix"sand dunes i. e. making the upper layers of the top soil more stable. However, it has been concluded that this in itself is not enough to arrest the problem. Furthermore, others have attempted to address the problem by adding artificial polymers to the top layers of soil to retain moisture. However, this has been shown to produce deleterious effects on the health of desert or local fauna.

As will be appreciated there is a need to arrest or reverse desertification such that land claimed by desertification can be converted back to land, which can sustain plant life and moreover, can be used for agricultural purposes.

Sapropel is a clay-like material, which is known as a source material for oil and natural gas. The term, sapropel, is derived from the Greek sapros, meaning"decayed"and pelos meaning"mud", and denotes a range of marine and lacustrine sediments containing organic and inorganic components. Sapropels range from the black organic oozes associated with the Silurian rock formations to variously coloured Holocene deposits.

Tabulated below is a list of countries and regions of the world where sapropel is reported to be found, together with a description of geological age.

Table 1 Continent Type of deposit Northern Europe: Finland Lacustrine Quaternary Sweden ditto Estonia ditto Latvia ditto Lithuania ditto Denmark ditto Netherlands ditto Baltic Sea Marine Quaternary Central Europe : Czech Republic Lacustrune Quarternary East Germany ditto Poland ditto Northern Italy ditto Romania ditto Southern Europe : Mediterranean Sea Marine Silurian-Quarternary Black Sea region ditto CIS: Belarus Lacustrine Quaternary Ukraine ditto Russia ditto Kaleria ditto Siberia: Omsk ditto Yakutsk ditto Nizhny Novgorod ditto Tomsk ditto The USA: Arkansas Lacustrine Quaternary Florida ditto Minnesota ditto Nebraska ditto Wisconsin ditto Canada Lacustrine Quaternary South America: Venezuelan coast Marine Quarternary Australia: Lake Cooroong Lacustrine Quarternary Africa: Namibia Lacustrine Quaternary Table 1: Countries and regions of the world where sapropel is reported to be found, together with description of geological age. Source: Andersons (1996).

Deposits of sapropel are mainly associated with sub-boreal lakes of Northern Europe, Siberia, Canada and the northern states of the U. S. A. Within Europe there are concentrations of sapropel-rich lakes in Karelia, Estonia, Latvia, Lithuania, Poland and the Czech Republic. Smaller amounts are reported to exist in Denmark, Finland, Sweden, the Netherlands, northern. Italy and eastern parts of Germany. Extensive deposits are also found in the Russian Federation, Belarus and Ukraine.

As will be appreciated, not all sapropels are found as lake deposits.

They may have their origin under peat formed in subsequent layers of vegetation. For example, sapropel from the Lake Sakhtysh region of north- west Russia is mined from beneath dry peat land.

Marine sapropels can also occur which are also Holocene. They are associated with the seas bordering arid regions, such as Namibia and the Sierra Nevada of Venezuela, and the eastern Mediterranean and Black Sea in Europe.

In the European regions, sapropels have been reported to form at a rate of lmm per annum. The organic components of sapropel accumulates in micro-laminations from a continuous rain of organic debris originating in vast reed beds bordering the lakes and is therefore autochthonous, i. e. originating from within the area of the lake. The inorganic component of sapropel is probably allochtonous, i. e. originating from outside the lake, but the migration of certain minerals such as calcium, magnesium and sulphur may originate from allochtonous organic sources.

Many sapropels are almost white-to-cream coloured. This reflects the amount of organic matter contained therein. As will be appreciated, as the organic component within the sapropel increases it will assume a darker colour; some sapropels are jet black.

Sapropels exhibit varying alkalinity. In this connection, sapropels having a pH greater than 7 are termed"lime-sapropels"and are usually characterised by the presence of several species of snails.

Sapropel can form in marine environments, as well as in freshwater lakes.

In marine environments, where the sea floor is too deep to allow oxygen to remain dissolved, sulphur-rich water acts as a reducing agent and provides an environment where organic debris can form sapropel. The sulphur itself is derived from the partial decomposition of plant and animal matter. In the areas of the sea beds where deposits of sapropel are found, the adjacent land mass is usually arid and well-leached of plant-growth supporting minerals. This may result in a correspondingly high supply of nutrients supporting a rich diversity of biota off the coast.

Typically, sapropel-rich lakes are situated on low-lying land. Generally, the lake bedrock is relatively insoluble and the lakeside soils tend to be podzols, from which nutrients are easily leached. As will be appreciated, the lakes themselves become sumps for these mobilised mineral salts, which are assimilated by reed beds that act as water-purifying agents. Sapropel forms on the lake floor in much the same way as peat forms on a raised or blanket bog.

The organic compound is derived from limnic (surface) vegetation, in particular, reeds. As these herbaceous plants pass through their annual cycle of growth and decay, they give rise to a continuous stream of organic waste material that accumulates on the lake bed. Here decomposition is continued in the form of digestion of the lignified tissues. Sulphur from protein bonding is liberated in the form of hydrogen sulphide gas, which combines with dissolved oxygen to form soluble sulphurous acid. In a typical sapropel lake, there is little replacement oxygen as the water tends to be stagnant, and after a while, all the available oxygen is used up such that decomposition slows down, and eventually stops altogether. Thereafter, the digestion of organic material becomes anaerobically controlled, giving rise to chemical reductions and the precipitation of certain minerals.

Some lakes have been accumulating sapropel undisturbed for over 10, 000 years. In some places, deposits of sapropel have displaced nearly all of the water. For example, Lake Zebris in Latvia has approximately a half metre depth of water remaining.

As will be appreciated not all sapropel deposits are found in the lacustrine environment. For example, in the Lake Sakhtysh region of northern Russia, water has receded in recent time and some of the former lake land has undergone a succession to moss or reed beds, with a layer of peat formed above the sapropel deposit.

In the past, sapropel has been utilised as a fertiliser. In this connection, the use of sapropel as a fertiliser has not been pursued due to its low nitrogen content, this, is despite the fact that many attempts have been made to increase its nitrogen content. In addition, due to its mineral content, sapropel has also been utilised in some countries as a supplement to animal feed.

According to a first aspect of the present invention there is provided a process for the re-vegetation of an area of land or a process for reversing or arresting desertification, the process including the step of : planting at least one plant to produce a windbreak, characterised in that at least one of the plants which is planted to produce the windbreak is planted in a growth medium which contains sapropel.

As outlined above, desertification results as much from the effect of wind action as from the intense heat from the sun. By employing the process of the present invention, the desertification process will be arrested and ultimately reversed, since the wind action will be filtered and broken up by the presence of the screens formed by the plants or trees (1 metre of windscreen affords 10 metres of leeward protection). This will result in upward air currents producing turbulence, which will cause the precipitation of moisture, the build-up of organic humus levels, and the stabilisation of the mobile upper layer of the area of land being treated. As will be appreciated, the success in reversing some of the human and natural causes of desertification will depend on establishing a critical mass of trees whose root system can quickly develop to exploit all available sources of water. This is achieved by the use of a growth medium containing sapropel. To this end sapropel not only possesses high cation exchange and water-retention capabilities, but also has unique salt- resistant/absorbent properties that enables it to attract and hold on to salt such that it not only protects the plant's roots from saline contamination, but also allows the plant's root system, including the plant's tap root and ancillary roots, to develop quickly, allowing it to exploit all sources of moisture or water available to it. That is, and based on its water retentive capabilities, sapropel has the capability of stimulating a phreatophytic reaction, i. e. it enables the plant's root systems to establish sufficiently enough such that it can reach and exploit the residual ground water arising from the water table and/or exploit scarce surface or air moisture. Once sufficient wind breaks and tree densities have been achieved, it will be appreciated that a micro-climate will be achieved within which it becomes possible to grow agricultural crops such as grains and pulses. In summary, by utilising the process of the present invention, it becomes possible to establish mass plantations of trees and shrubs in arid or desertified areas of land with minimal irrigation due to the use of sapropel.

Preferably, the growth medium is formed by mixing soil, sand or earth, local or otherwise, with sapropel in a ratio of between 15: 1 and 1: 1 by volume, preferably between 15: 1 and 3: 1 by volume. In a preferred embodiment, the growth medium is formed by mixing soil, sand or earth, local or otherwise, with sapropel in a ratio of 5: 1 by volume, preferably 3: 1 by volume. It is to be understood that the soil, sand or earth that is mixed with the sapropel need not be obtained from the surrounding area, but can be brought in from other areas.

Preferably, mycorrhizal inoculants to aid the stimulation of plant growth is also added to the growth medium. Although non-limiting, a preferred inoculant includes vesicular-arbuscular mycorrhizae.

Preferably, the growth medium including the mixture of sapropel and soil or earth is mixed with water until field capacity is reached i. e. no more water can be held. At this point, the resulting mixture has a consistency akin to wet cement.

Preferably, the at least one plant is planted within about 0.5 litres of the growth medium. Further preferably, the growth medium is moulded around the roots of the at least one plant being planted. Further preferably, the at least one plant is planted in a pit at least 3cm below nursery level. Preferably, once planted, the method includes the step of watering the at least one plant.

Further preferably, the at least one plant is surrounded by means to reflect the sun's rays. For example, this can be achieved by surrounding the at least one plant with surface stones, porous matting or sand.

Further preferably, with a view to protecting the planted plants from being eaten by local wildlife or livestock, the plants could be surrounded by tree guards and/or attached to stakes and/or the whole area could be cordoned off.

In a further aspect of the present invention there is also provided the use of sapropel as part of a growth medium to arrest or reverse desertification.

With a view to illustrating the effectiveness of sapropel as a growth medium for use in desertified areas, the following investigations and studies were conducted.

METHODS EMPLOYED Over a period of 30 months, three types of crop were grown in a simulated desert medium. 50% of the crop plants were grown in a medium amended with sapropel so that data could be gathered and compared with that produced by plants grown in an unamended desert medium. The crop designs are tabulated in Table 2 below.

Crop types.

Design nos. Period 1-10 11-20 21-30 31-40 41-50 51-60 + sapropel - sapropel + sapropel -sapropel + sapropel-sapropel First Horden H. vulgaris Arachis A. hypogea Vigna V. unguiculata vulgaris hypogea unguiculata Second Cl ? amaedorea C elegaiis Rosmarinus R. officinalis Hibbertia aspera H. aspera elegans officinalis Santolina S. chamae- Chamae-cyparissus cyparissus Third Ligustrum L. ovalifolium L. ovalifolium L. ovalifolium L. ovalifolium L, ovalifolium ovalifolium Table 2. Chart showing designs for cultivation of three simultaneous crops in a desert substratum.

In the first design (Table 2), crops were chosen that were indigenous to the badlands of South East Africa. These were Barley (Hordeum vulgare), Cowpea (ligna unguiculata) and peanut (Arachis hypogaea). Seeds of these plants were sown directly into the substrata and grown to fruition. Over the growth period the plants were monitored for pests and diseases.

In the second design (Table 2), shrubs tolerant of arid soils were chosen: Cotton Lavender (Santolina chamaecyparissus), Rosemary (Rosemarinus oÇcinalis), Hibbertia (Hibbertia aspera) and the Parlour palm (Chamaedorea elegans).

The third design (Table 2) contained one tree species: oval-leafed privet (Ligustrum ovalifolium). It was intended to use species which were tolerant of high temperatures such as would be found in an arid region. Santolina chamaecyparissus and Rosemarinus officinalis are indigenous to the Mediterranean Maquis, Chamaedorea elegans is a native of the Brazilian rainforest; and Hibbertia aspera originates in the Australian Bush. Ligustrum ovalifolium is Japanese in origin and tolerant of high temperatures.

Experimental design An unheated glasshouse was used for this study. In addition, so that a comparison could be made with conditions prevailing within a subtropical desert, the maximum and minimum temperatures within the glasshouse was recorded daily.

Sixty 100 mm diameter plastic waste pipes of lm length and numbered 1-60 were sunk into a bed within the unheated glasshouse and filled with a simulated desert growing medium, which consisted of a 30 cm basal column of South Cerney hoggin, a limestone river sediment from the Cotswold area, and an overburden of 65 cm depth of washed Holm sand, a coarse-grained sand from the Bristol Channel.

The numbers 1-60 were distributed randomly and the pipes placed in four groups of 15 pipes each. Numbers 1-10,21-30 and 41-50 were amended with sapropel by mixing 50 cm3 of the sediment with 150 cm3 of the surface Holm sand (see Fig. 1). Over a period of 30 months, three types of crop were grown and their progress recorded. At fruition, final parameters were measured in one destructive harvest. Seeds and transplants were watered initially with approximately 1 litre of tap water to ensure settlement of growth media, thus reducing the chances of early desiccation. All subsequent irrigation was applied to the glasshouse basal substratum so that capillary action would maintain moisture content thereafter.

At fruition, growth parameters of haulm and root dry mass, pods and seed production were measured.

Root and haulm development, and fresh and dry mass were the principal growth parameters measured with the shrubs and trees. The results were tabulated and presented in the form of graphs of comparison between plants grown in amended and unamended substrates.

The privet was grown purely to test the ability of the plants to survive in the simulated desert environment. Accordingly, sixty one-year-old rooted cuttings were purchased from Wyevale Nurseries PLC of Hereford and individual cuttings were planted in the desert substrate columns. Thirty of the columns were amended with 100 g composted black sapropel. The plants were watered in with 1 litre of tapwater each day for five days to encourage early establishment. Thereafter water was applied only to the basal substratum as before.

Where possible the results, being normally distributed, were tested statistically using Analysis of Variance (ANOVA) and Tukey's Multiple Comparison Test (Maidment, C. (1993)"An Introducto7y Guide to Statistics" Bath Spa University College).

RESULTS.

Use of sapropel to amend an arid medium as a growth substrate for a range of plant species.

A mean mass of 51g per plant at harvest for barley in the amended substrata, compared favourably with 29 g per plant in the unamended media (Fig. 2). Although fresh mass was much lower with peanut and cowpea, plants in amended substrata had higher fresh masses at 4.2 g and 5.9 g, than plants from unamended substrata at 1.1 g and 3.8 g respectively. The mean seed production reflected these differences. With 40 seeds per plant for barley and 8 seeds per plant for cow pea, more seeds were recorded for plants in amended substrate, than unamended, where a mean 20.5 and 6 seeds were recorded respectively (Fig. 3). Peanuts in unamended media produced no flower and therefore no seed.

As shown in Table 3 below, fresh weight yields for barley and peanut, and seed number for the same plants were significantly different from barley and peanut crops harvested from unamended media (ANOVA: F=36.4, p=0. 01). Results for cowpea were not significantly different at 95% confidence level. Medium + sapropel Barley * Peanut Fm Cowpea fm Barley fin Peanut seeds * Cowpea seeds seeds |Barley Peanut Cowpea Barley Peanut Cowpea Medium-sapropel Table 3: fresh mass and seed number. *denotes significant differences between plants grown in amended and unamended media at 99% confidence level. were determined using Tukey's multiple comparison procedure (Tukey, J. W. (1993) The Collected Works of John W. Tukey, Volume VIII : Multiple Comparisons, 1948 1983. (H. I. Braun, ed. ) Chapman and Hall, New York).

Hibbertia plants from amended substrates produced greater fresh mass of haulms and roots at 1.7 g (haulms) and 3.75 g (roots), than plants grown in unamended media where fresh masses of 0.46 g (haulms) and 0.33 g (roots) were recorded (Fig. 3). Similarly Rosemary plants from amended substrates produce greater fresh mass of haulms and roots at 92 g (haulms) and 16.5 g (roots), than plants grown in unamended media where fresh masses of 32.7 g (haulms) and 8. 2 g (roots) were recorded (Fig. 5). The palm also produced greater fresh mass from amended media but the plants did not make substantial growth in either compost design. At 1.45 g (haulms) and 0.64 g (roots) the plants grown in amended media were not much different to those in unamended substrate where fresh masses of 1.23 g (haulms) and 0.25 g (roots) were recorded.

Fresh mass of Santolina (Fig. 6) indicated that shoots and roots from amended media were significantly greater than those from unamended media.

The graph shows that plants from amended substrates produced greater fresh mass of haulms and roots at 460g (haulms) and 356g (roots), than plants grown in unamended media where fresh masses of 355 g (haulms) and 352 g (roost) were recorded.

Significant differences between plant material harvested from amended and unamended media are summarised in Table 4 below.

Medium + sapropel Rose- marinus Hibbertia haulms ** Santolina haulms Rose- haulms * marinus Hibbertia Roots Santolina roots ** roots Rose-Hibbertia Santolina Rose-Hibbertia Santolina , marinus, Marinus Medium-sapropel Table 4. Selected shrubs: fresh mass of haulms and roots of Rosemarinus officinalis, Santolina chamaecyparissus and Hibbertia aspera grown in a simulated desert medium amended or unamended with sapropel.. *= significant difference at 95% confidence level. ** = significant differences are at 99% confidence level. n=10.

Dry mass of shoots and roots of Rosemarinus oXicinalis (Fig. 7) produced figures for plants grown in amended and unamended media that were significantly different. At 25. 6 g (haulms) and 11.7 g (roots) plants grown in amended media produced greater dry masses, than those from unamended media, where fresh masses of 11 g (haulms) and 7.8 g (roots) were recorded. A similar pattern was observed in the results obtained from Santolina claamaecyparissus (Fig. 8) where plants from amended substrates produced greater fresh mass of haulms and roots at 44.5 g (haulms) and 9. 8 g (roots), than plants grown in unamended media. Here dry masses of 27.9 g (haulms) and 4.1 g (roots) were recorded.

The final trial which used oval-leafed privet (Ligustrmn ovalifolimn) recorded the establishment and survival of 30 plants in amended and 30 plants in unamended sapropel. Average weekly temperature was recorded (Fig 9).

Surviving plants were counted fortnightly and a marked reduction from 30 to 9 after seven weeks in the survival of plants grown in the unamended substrate (Fig. 10) was observed.

With reference to our investigations, it is evident that, as an amendment to desert substrates, sapropel performed well. Taking cognisance of Bunt's criteria (Bunt, A. C. (1976). Modern Potting Composts, Allen and Unwin, London) that a viable compost must include water, nutrient retention and porosity, it is clear that desert and arid soils cannot provide these conditions in their natural state. Significant differences in growth performance between amended and unamended preparations are noted in all three groups of trial plants.

In addition to the above, the growth parameters measured, clearly indicate that sapropelled subjects gave rise to better performance than the unamended media. Others such as barley exhibited resistance to the prevailing conditions and prove to be a trial crop from which valuable data could be gathered. In barley and cowpea, increasing plant mass was consistent with greater seed production and in the former, significant differences occurred between performance on amended and unamended media.

Such results were repeated by the Saiztolitia, Rosmarinus and Hibbertia.

These are plants which grow naturally in arid scrubland and would be resistant to arid conditions. Even so, a limit exists to the endurance of these plants.

Early root development is a vital factor in the late survival of any plant.

Although all plants were well watered in at the commencement of the trial, the inability of sand to retain moisture meant that water became a scarce commodity within a few days. As in a desert situation, upward percolation of ground water counteracts this deficiency to some extent. However, as ambient temperatures increase during the day, so evaporation of ground water is speeded up and ultimately a layer of dry medium develops, the depth of which is influenced by the size of constituent particles and the intensity of internal and external temperatures. Even in the unheated glasshouse these can reach as much as 53°C and night time temperatures can fall as low as 4°C.

Such temperature fluctuations experienced in an English glasshouse in summer (4-48°C) are common in desert environments and the indigenous flora has evolved to conflict with these. For example, cacti and succulents (xerophytes) hold moisture in modified lesion stems; other plants such as rosemary and thyme develop hardened leaves with waxy cuticles for reflecting sunlight, the new foliage and flowers being restricted to early in the season when ambient temperatures are lower. Yet other plants produce a phreatophytic response to fluctuating water ability. This involves the production of elongated tap roots for residual water often at some considerable depth. Whether this is an evolutionary process or merely an automatic geotropic response is uncertain. Mesquite and arrow weed are phreatophytes of the Nevada Desert, U. S. A.

Grapevines and figs tend to exhibit phreatophytic responses, so much so that it is often desirable to cut the tap root in order that the lateral group is produced that will exploit nutrient supplies from richer soils near the surface to improve fruiting.

Traditional tomato curing, "ring culture", exploits the plants natural tendency to produce lateral common nutrient seeking roots and simultaneously supplying a reservoir of water for tap root development.

What is clear is that an element of stability whereby the plant can derive a modicum of soluble nutrient is a prerequisite for tap root development. This early establishment is reliant on the presence of soluble nutrients in the planting medium, as well as enough water to maintain its acidity and mass flow of functions to the plant itself. In an unamended desert medium there is not normally enough water to maintain these requirements, explaining why so little vegetation is present In the light of our results, it is evident that sapropel would hold on to the moisture long enough to anchor a plant and allow a phreatophytic response in a range of trial plants. Successful plants were characterised by a fringe of lateral roots at the base of the stem from which emerge several elongated structures. These usually extended to the rooting medium, Holm sand and Cerney gravel and into the glasshouse bed. As observed by us, the subjects grown in unamended media possessed significantly shorter tap roots and evidence of lateral root development was reduced.

Plants from amended media usually had hardened sapropel encasing lateral roots, suggesting that sapropel was prone to eventual drying out, even when submerged in the desert sand. Yet the time taken to reach this stage was consistent with that measured in the early drying trial and this suggested that the slow release of water facilitated the production of the lateral root so that the plants were well established by the time a tap root began to develop.

In addition to the above, comparison of the fates of Ligustrum ovalifolium grown in amended and unamended media showed consistently more plants surviving from amended media, both at 15 weeks and 30 weeks.

Why there should be a steep decline in survival after the first month among plants of both treatments could be traced to the uneven root development of the original plants randomly distributed between the two designs. During the relatively cool, diffused daylight of March and early April those plants with well developed root systems could establish in the still damp substratum. As ambient temperature rose, only those plants with well established root systems could exploit available water for transpiration. Even plants established in the substrate amended with sapropel would not tolerate the increased temperature if their roots were not properly developed. Others in the same design died back, but then recovered when a balance between leaf area and root development was achieved. No such recovery was recorded amongst plants growing in the unamended substratum and the few plants surviving were those with well developed root systems at the transplanting phase.

Therefore, in the light of our investigations, it is evident that plants planted in an amended substrate or growth medium including sapropel fared much better in such climatic conditions, than those planted in unamended growth mediums.

In a further aspect of the present invention there is provided the use of sapropel within a growth media as a water retentive agent.

Preferably, the growth media or medium is formed by mixing soil, sand or earth, local or otherwise, with sapropel in a ratio of between 15: 1 and 1: 1 by volume, preferably between 15: 1 and 3: 1 by volume. In a preferred embodiment, the growth medium is formed by mixing soil, sand or earth, local or otherwise, with sapropel in a ratio of 5: 1 by volume, preferably 3: 1 by volume. It is to be understood that the soil, sand or earth that is mixed with the sapropel need not be obtained from the surrounding area, but can be brought in from other areas.

Preferably, mycorrhizal inoculants to aid the stimulation of plant growth is also added to the growth medium. Although non-limiting, a preferred inoculant includes vesicular-arbuscular mycorrhizae.

Furthermore, there is also provided a process for establishing a layer of vegetation over an area of land, the process comprising the steps of : providing a layer of sapropel over the area of land; substantially covering the layer of sapropel with a layer of top soil; and planting seed in the layer of topsoil.

As will be appreciated, and based on the discovery that sapropel has water retentive or retaining characteristics, it will be appreciated that based on the present disclosure sapropel would reduce the irrigation requirements for the resulting vegetation, for example, grass, to become established and thrive.

Preferably, the vegetation is grass.

Further preferably, the layer of sapropel is about 5-15cm in depth.

Further preferably, the layer of sapropel is placed on top of a permeable liner, preferably, a geotextile permeable liner. This has the advantage in that the permeable membrane will prevent the sapropel from decomposing into the subsoil while allowing for permeability of air and water and avoid any risk of the vegetation e. g. grass from becoming susceptible to rot or other disease.

Preferably, the area of land is part of a golf course or a race course or an area of land utilised for sport and leisure activities, e. g. , football, hockey and rugby pitches.

There is also provide an area of land vegetated in accordance with the process of the present invention.

In the present specification"comprises"means"includes or consists of' and"comprising"means"including or consisting of'.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.