Showing posts with label king shaka international airport. Show all posts
Showing posts with label king shaka international airport. Show all posts

Wednesday 15 October 2014

A few thoughts on creating a near to Natural Grassland

Creating a near to Natural Grassland is far easier said than done but it is certainly not impossible as can be seen from the photograph below taken of a portion of one of my grass gardens I have been growing for the last six years in my in my own garden at Mount Moreland.

Berkheya insignis

Although I have been experimenting since the mid 1970´s with growing very many grassland plants species and in establishing and managing grasslands on a small scale there are still many questions than remain unanswered. There are no doubt many methods and combinations of methods that can be successfully used the scale of the project will usually determine the method used to establish your grassland.

I will only present one method in this article the method I would use on a small to medium scale in the re-creation of grassland habitat, it is easy enough to adapt to the small scale home garden grassland. Large scale re-creation of grassland needs to be looked at in a very different light, for such large scale creation of grassland much reliance would need to be put on assisting and guiding natural processes of regeneration to do the work. Below I have presented a few short guidelines that need to be taken in to account when attempting to create a small to medium sized grassland the rest is probably going to be up to natural processes beyond your control. These are just a few guidelines gained from about 40 years of experimenting, as I certainly do not have all the answers after so many years of trying, managing your own grassland is going to be a challenge that will be most rewarding

Grassland habitats bring large numbers of insects in particular bees and butterflies into the garden and surprising to many the grasses bring in the most. 

Anthericum saundersiae

Many other small creatures are at home in grassland
such as  some of the smaller skinks including burrowing skinks and plated lizards. The golden mole is also a resident of my grasslands. 

Weeds and their control

One question that still remains very much unanswered and may probably never be satisfactorily answered is the matter of weed control. Without exception any natural grassland that has been disturbed or put to another use very rapidly becomes infested with both foreign as well as indigenous weeds, as well as woody plant invaders such as Chromaleana odorata. Another huge problem that is often encountered in former disturbed areas and abandoned farmlands is Cyperus esculentus, (yellow nut sedge or nut grass). This presents a huge problem for anyone who has in mind to create a suburban grassland garden or to re-habilitate grassland on a much larger scale on abandoned farmland. Clearly the biggest problem in establishing and managing an establishing grassland is the control of the weeds that will germinate and grow in profusion as soon as disturbance occurs such as the preparing of the seed bed and the planting of grass seed or the planting of growing plants takes place. In fact the control and management of weeds in the grassland is the key to success and is always going to present huge problems after the flowering plants are introduced into the grassland as thereafter selective herbicides can no longer be used.

Reducing the number of weed seeds and nut sedge in the soil before planting begins will certainly have a major influence on the success of the project as failing to do so will ensure huge competition with the grass plants one is wanting to establish, in particular on large scale projects where grass is being planted by means of seed over vast areas.
The old saying more haste less speed certainly is the case in establishing a stable grassland community. It would certainly be of great benefit to plan the establishment of the grass land with great thought and detail then to go about the project methodically taking into account the weather conditions that nature presents you with at the time of establishment.

Choice of grass species


Melinis nerviglumis

From the very beginning it must be taken into account that a grassland is not a grassland without grass plants they play by far the major role in the ecosystem the larger the number of species the better the grassland.
The choice of grass species to be planted will be determined by a number of factors in particular the nature of the soil, whether it is sand, loam or clay, the lay of the land for instance is it flat or sloping, or does it face north, south, east of west. The soil moisture and drainage are also very important factors to consider in choosing the species of grass to be planted as different grasses have different soil and moisture requirements. For the small home garden low growing less vigorous decorative grasses with low leaf production are probably the ones to choose from. In most cases it would be most practical to plant the grass seed in situ.
For the small home garden it would probably be an option to grow the grass plants needed to establish the grass garden in containers in a separate nursery area to be planted later together with the grassland forbs into their final positions in the grass garden.
Most if not all of the seed that will need to be used is probably going to need to be specially collected and processed as the commercial seed merchants only stock improved varieties of our local grasses that have been specifically selected and bred for producing pastures. For projects I have undertaken I have mostly collected and dried my own seed.
For the smaller project some of the grass species required can be bought from nurseries or nurseries will grow them for you.
Try the internet it is amazing what you can find for sale or what you can obtain if you make your requirements known

Choice of grassland flowering plants


Thunbergia atriplicifolia

Here similar factors come into play as for when choosing grasses for the small home garden and be sensible do not try to grown large or vigorous growing plants because  they will soon cause problems, also avoid weedy species that multiply rapidly by seed. Make sure that a good number of legumes are included in the selection of the plants to be used as they play an important role in the ecosystem in particular by providing nitrogen to the grasses and other plants.

For many species it is probably better to grow the plants needed to establish the grass land or grass garden in containers in a separate nursery area to be planted out later into their final positions in the grass land or garden at the appropriate time. Many of the grassland forbs, in particular those with bulbs or large underground storage organs are best grown from seed planted into beds in the ground or raised beds. When it is the correct time to plant them out usually after the first spring rains simply cut back the above ground growth and then plant them out directly into the ground. This method vastly reduces the losses when planting out into the field, in fact any plant that can be cut back should be cut back before planting out into the field.

Plant sources

Nurseries are the first choice for many home owners wanting to establish a small home garden grassland
in particular those who do not have the skills or time to produce their own plants.
Another option is to rescue plants from development sites, here it would be necessary to obtain the landowners permission and possibly permits form the authorities in the case of protected plants.
Grow your own. Collect seed and or vegetative propagating material and grow the plants required in a nursery established for the purpose, this would be essential for larger projects.  Here again it would be necessary to obtain the landowners permission and possibly permits form the authorities in the case of protected plants.
Try the internet it is amazing what you can find for sale or what you can obtain if you make your requirements known

Preparation of the site for planting the grass seed

The site to be planted needs to be freed of all rubble and other foreign materials, this may sound rather obvious to most people but does not appear to be so to some. The next step would be to spray the entire area with a non selective herbicide to remove all unwanted vegetation. Burn, turn by hand or plough the entire area to create a fine seed bed then smooth but do not compact the surface ready for planting at the same time incorporating a pre-emergence herbicide for broad leafed weeds if one is being used. It is important to sow the seed as soon after preparation as is possible. If there is a serious problem with nut grass it may pay to deal with this problem as best one can before doing final seedbed preparation and the planting of the grass seed.
If you need tractors and farming equipment try your local farmer or place an ad on the internet.

Planting the grass seed

Standard agricultural seed drills or spreaders will be suitable for planting many of the seeds however some seed may need to be hand distributed if the machinery available or the seed being planted is not suitable. Hydroseeding is also a viable option if the equipment is available at a reasonable cost. Some grasses that have a low seed production can only be established by planting live plant material.

Additional notes for the home garden


Kniphofia tysonii

Position your grass garden in as open a position as possible because grassland need lots of sun and does not particularly like to be in shadow for too much of the day. The other big consideration is the nearness to trees because their roots compete for both nutrients and water if they can reach. 
Group your plants for effectiveness this also promotes good cross pollination and seed production
Many plants of the family Compositae are very showy and do well such as Gazania, Helichrysum, Berkheya, Vernonia, Senecio.
The small decorative home garden grassland would benefit from a light topdressing of well rotted compost and a little well balance fertilizer at the beginning of the growing season.
Hand weeding is going to need to be done to keep the grassland free of unwanted weeds
In a small grassland natural processes can not be relied upon to keep it in equilibrium therefore there is going to be the need for the annual or continual removal of excessively vigorous plants and those that multiply too freely and for others that find it hard to maintain their presence replacement on an annual basis will be required.
Keep a list of the plants that were planted and propagate or buy the ones that do not readily reproduce by themselves when replacements are needed. 
Be vary wary of planting plants that can easily become weeds such as Justicia lutea and vigorous creeping plants
Watering may be beneficial at times in particular if one burns early to promote an early flush of spring flowers as I do on portions of my grassland.
The grass must be allowed to start drying out mid summer to early autumn and winter so that the plants can rest. After the aloes have flowered I then cut or burn the grass and irrigate to start the spring off a little early.
When planning to burn warn your neighbours! Plan to burn small areas at a time and before burning water the surrounding areas very well and do not forget to be on standby together with your neighbour with your hosepipes in hand and turned on. 
Do not expect your grassland to look good all year round because it must rest and dry out in the winter to look its best in the springtime after the rains arrive.

Managing the grassland

When establishing grassland on a larger scale it is going to be necessary to establish a relatively stable grassland until annual weeds have been sufficiently suppressed by the grasses because once the broadleaf plants have been added one can no longer control the broad leaf weeds by chemical means. Grass weeds that may become a problem will need to be spot treated with a non-selective herbicide or be removed by hand.
The grass must be mowed and not be allowed to grow too long in the first months after establishment so as to allow those grasses that germinate or grow slower to reach a reasonable maturity before slowly allowing the grasses to grow taller between mowing, if this is not done the slower species will simply die out and the faster growing species will dominate. I believe it would be most beneficial to graze the grassland once well established with goats and sheep and possibly even cows in a controlled manner to promote healthy growth of the grasses and to maintain the highest possible plant density. In fact I am presently doing trials using an Nguni Sheep and an Nguni Goat to see the effect on the plant populations in my own grasslands.

My gardening assistants Imvu and Imbuzi inspecting newly planted grasses

In the first years both during and following establishment it would probably be beneficial to burn the grassland annually in particular if the grassland is not grazed or the grass is not cut during the year, thereafter the decision to burn or not to burn must be based on the condition of the grassland at the time when burning should occur.

Planting the grassland forbs

The forbs and other grassland plants must be introduced to the grassland at a much later date the soonest being the following growing period. Thereafter any weeding out of weeds with herbicides will need to be done very carefully if at all or by hand pulling making sure to deal with each weed specie before it has the opportunity to set seed.

Some of the plants that have done well for me in my ornamental grass section

Grasses

Melinis nerviglumis
Panicum natalense
Andropogon eucomis
Eragrostris racemosa
Eragrostis capensis
Themeda triandra
Hyparrhenia filipendula

These are all small varieties with low leaf production which are ideal for an ornamental grass garden, those with a high leaf production are more ideal as for larger natural grasslands and for development as pasture grasses but not for your ornamental home grass garden.

Flowering plants


Dianthus zeyheri

Aloe maculata
Anomatheca laxa
Anthericum saundersiae
Aster bakerianus
Berkheya insignis
Berkheya speciosa
Berkheya umbellate
Bulbine abyssinica
Bulbine asphodeloides
Crocrosmia aurea
erbera ambigua
Gerbera piloselloides
Gladiolus daleni
Gladiolus woodii
Helichrysum aureum
Hypoxis angustifolia
Hypoxis hemerocallidea
Hypoxis rigidula
Kniphofia tysonii
Plectranthus hardiensis
Ruellia cordata
Scadoxus puniceus
Senecio coronatus
Thunbergia atriplicifolia
Thunbergia natalensis
Vernonia capensis
Vernonia hirsutus
Vernonia natalensis


Xysmalobium undulatum

Other Grasses
I presently have the following grasses plus a few more in the form of seed or seedlings that may have survived the drought growing in different habitats in my garden

Acroceras macrum                                           
Agrostis eriantha
Aristida junciformis
Bothriochloa insculpta
Brachiaria brizantha
Cenchrus ciliaris                                                
Chloris gayana
Cymbopogon plurinodis                                    
Cynodon dactylon
Dactyloctenium australe                                     
Digitaria eriantha
Digitaria sanguinalis
Ehrharta erecta
Eleusine coracana                                             
Eriochloa meyeriana                                                                                      
Eragrostis ciliaris
Eragrostis curvula
Eragrostis racemosa
Festuca scabra
Hemarthria altissima                                          
Hyparrhenia hirta                                              
Hyparrhenia sp silver foliage
Hyparrhenia sp very tall yellow stem
Hyparrhenia filipendula
Imperata cylindrical
Ischaemum fasciculatum                                    
Leersia hexandra
Melica racemosa                                                  
Melinis nerviglumis
Melinis repens                                                  
Oplismenus hirtellus
Panicum schinzii
Panicum deustum
Panicum maximum
Panicum natalense
Panicum repens
Setaria megaphylla
Setaria sphacelata var sericea
Setaria plicatilis
Setaria verticillata
Sorgum bicolor
Sporobolus africanus
Sporobolus fimbriatus
Themeda triandra                                           




Michael Hickman
Ecosystems Manager
Landscape Design Specialist


15.10.14


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Saturday 3 May 2014

Some thoughts on the rehabilitation of sugar cane land into natural like grassland in the coastal regions of northern KwaZulu-Natal


A brief overview
In my professional opinion I believe it is an illusion to believe that in the short term one can recreate natural like grassland on a large scale. I believe that the best and most cost effective method is to set the process into motion, to guide it, to manage it and to keep it free of invasive aliens as best as can be done. Clearly the more the money that is invested into the project the quicker the results will be, but the higher cost can never be justifed.

Aloe maculata and berkheya spiciosa growing in my grassland at Mount Moreland


Unless one works in a cost effective manner together with nature in today’s economic climate it is going to be impossible to justify the expense of re-habilitation.  

If I was set with the task of re-habilitation of a large tract of sugar cane land into natural like grassland I would set about the task using the system and methods described in the rest of this brief article.

In my opinion there are many approaches that would deliver acceptable results and that there is no absolute right or wrong. We do not know for sure what was there before sugar cane but can give it a guess based on experience, local knowledge and looking at sites in surrounding areas with untouched or minimally damaged grassland. There could very clearly be elaborate and colorful designs put forward by office experts where nature will not comply with the designers wishes. Designs that would dazzle but that could never be implemented no matter how much money one invests into them. When dealing with nature there are certainly no guarantees that any expert can give. Regardless of our skills or lack of skills nature will have the last say the sooner we realize this the more successful we will be and the more money we can save arriving at an acceptable result.

As a case study I propose the re-habilitation of portions of sugar cane lands at the new Durban King Shaka International Airport as I know this area well having flown many hours low over the leveled areas since work was started on the site in about April 1971. I also often landed on the site long before the present airport was built. I now live at Mount Moreland immediately south of the airport. In addition I have been involved in the project in one way or another including planning of the re-habilitation since 3 August 2007.

On site during construction King Shaka International Airport Durban

After the initial earthworks were completed at the then La Mercy Airport the project was abandoned without any re-habilitation work whatsoever being implemented on site. Within a relatively short space of time weeds and grasses colonized the site and over the years many of the local grasses and grassland plants found there way onto the site.

Method
There are as many possible methods as the days in the year, which method is correct and which method is not can probably never be evaluated, clearly on a large scale cost will be a major factor so any method that works with instead of against nature saving cost is going to be the way to go.

Before attempting to engage in rehabilitation activities one must first try to reconstruct in ones own mind the nature and annual life cycles of the grasslands of the past, some indications can still be found in the rural areas nearby that have not been affected by sugar cane farming.

In my professional opinion the method that requires the least human intervention and the maximum use of natural processes to bring about the re-creation of natural like grassland is going to be the only sensible and economical approach in the short, medium and long term. This approach certainly will not give the quickest results but will most certainly be financially justifiable and will give a good result in the end.

In most of the areas not directly associated with the airport such as the runway, terminal and service areas where earth works were undertaken the growing of sugar cane continued on a lease basis in many areas right up to this day badly depleting marginal sandy soils of the last of their nutrients until they were in many cases finally abandoned.

Albuca setosa growing in my grassland at Mount Moreland

Starting the process
Harvest the sugar cane wait for he sugar cane to start growing when there is sufficient growth to be able to deliver a lethal dose of Glyphosate spray the cane and let nature continue the process.

Annual weeds
Since the natural vegetation was destroyed and sugar cane was first planted on this land from about the 1850´s no other crop has been grown on it. Over time the sugar cane has acted as a huge trap trapping vast amounts of windblown seed of invasive alien weeds including vast amounts of annual weeds which are now stored in the soil seed bank. Due to the sugar cane inhibiting the germination of the weed seeds most never germinated those that did germinate soon died as the cane grew and robbed them of light. When the sugar cane is finally removed and the factors inhibiting the germination of the weed seed has been removed the annual weed seeds germinate in their countless millions after the first rains. Small quantities of local perennial grasses mainly Panicum maximum also germinate together with the weeds after the sugar cane is removed and they receive sunlight, once the weeds have completed their life cycles and have produced their seeds and have died the grasses have a chance to grow, to cover the ground and to produce their own seeds in turn. If left to nature after a few cycles the grasses gain the upper hand and the annual weeds almost disappear, to be an insignificant component of the resulting grassland. These same annual weeds can also be found in the few remaining natural grasslands in the immediate vicinity and when portions of these seemingly stable natural grasslands are disturbed masses of these same annual weeds germinate, slowly to be naturally suppressed by the natural grasses and other plants.

As far as attempting to eradicate annual agricultural weeds such as Bidens pilosa, Bidens bipinnata, Conyza bonariensis, Ageratum conycoides etc. by chemical or mechanical means in rehabilitation and alien plant eradication projects at the King Shaka International Airport or elsewhere in the greater Durban area is concerned, I in my professional opinion believe that it is an impossible task due to many factors beyond our control.


Ageratum conycoides the most numerous annual weed at this time of year

Inappropriate use of the herbicide Glyphosate and poor cultural practices on surrounding farmlands and derelict and poorly managed land around the city has greatly increased the number of these agricultural weeds, which release their windborne seeds to re-infesting the areas that have been cleared. In my professional opinion a good healthy cover of natural grasses and grassland plants is the only sensible solution to suppress the numbers of these unwanted weeds.

This process does however not occur where perennial alien weeds are concerned and if left to nature they generally quickly become dominant making it necessary to remove them.

If left to nature it would be many years and some not at all before many of the other grasses and grassland forbs make their way to the site therefore some help is going to be needed to help them to get on site and to help them to establish themselves.

Obtaining and growing seed
Obtaining most of the seed needed to re-introduce the required plants both grasses and forbs to the site is going to present many problems as very few are available commercially and many aer close to impossible to grow using conventional methods. Here is where a very good knowledge of our local plants in particular knowing how to grow them and introduce them into the grasslands and innovative thinking based on this knowledge is going to be vital to the success of the project.

Berkheya speciosa in my garden at Mount Moreland

With many of the plants that need to be introduced into the grassland seed is neither able to be collected in the wild or the plants do not take kindly to propagation and cultivation so a good knowledge of the plants is essential and innovative methods need to be employed to be able to introduce them into the grasslands. So as to protect my specialist know how in this area I am not going to go into any detail in this article.
The planting of certain grass seeds in particular some of the grasses with long awls such as grasses in the genus Hyparrhenia presents problems all of its own for instance they can not be planted by seeding machines because they tie themselves together in tight bunches and can from my own experience only be hand distributed unless the awls can somehow be removed from the seed without damaging the seed.


Hyparrhenia hirta growing in my grassland see the very long awls on the seed

Management of developing grassland
Management of developing grassland poses many questions as to the correct management of the emerging natural grassland for instance at some point in time additional species need to be introduced and this is going to be very difficult if there is a thick cover of Panicum maximum that dominates the landscape not allowing other grasses and Forb seeds to germinate and grow just as was the case with the sugarcane dominating the landscape before it. Fire is clearly a tried and tested method to remove the dense grass cover once per year but I believe this is both damaging and inadequate if done alone in particular on developing grasslands. Burning removes moribund grass very effectively, promotes the germination of seed, it promotes the growth and variety of grassland forbs but looses nutrient to the atmosphere. Burning certainly helps control the rampant growth of the dominant pioneer species in this area Panicum maximum.
Burning alone removes large amounts of carbon returning it back to the atmosphere in addition to other vital minerals and organic compounds which are lost to a system which has already been impoverished due to over 150 years of sugar cane cultivation.
Burning of developing grassland following the removal of sugar cane

Domestic livestock
In the natural grassland as had occurred on site before the arrival of the white man who removed it and planted sugar cane the grasslands of this region were formed by the interaction of grazing and browsing animals both wild and domesticated and the actions of man who in the absence of natural fire set fire to the grassland after the first spring rains.
It long believed that the Nguni cattle, goats and sheep arrived in southern Africa with the Nguni-speaking people, ancestors of today's Zulu, Xhosa and Swazi people.  However, recent research has revealed that the cattle were probably introduced into southern Africa by the Khoisan-speaking people in around 600 and 1400 AD this is much earlier than originally thought. The Nguni-speaking arrivals in southern Africa quickly assimilated the cattle skills and husbandry techniques of the Khoisan. 

Since then, these animals have played an important environmental role in the development of the grasslands in the areas that were settled by these people. 
It is clear in my mind that animals must be part of the equation as they not only remove grasses and other plants allowing for light to periodically reach the level of the soil which fosters a much larger varieties of plants to establish and to maintain themselves this I have observed in the wild and proven in experiments that I have performed. In addition to periodically removing unwanted top cover in controlled grassing vast numbers of organic compounds and nutrients are returned to the impoverished soil. As it is not practical to do controlled grazing with wild animals and because domestic livestock also played and important role in managing the rolling grasslands of KwaZulu-Natal before the arrival of the white man I propose the use of Nguni cattle, Nguni goats and imvu the Zulu sheep to do this valuable task for us. Large herds of wild grazing and browsing animals and pastoral activities by native tribes has clearly had a large impact on forming the natural grasslands in this region before Europeans arrived and ripped most of it up to plant mono-cultures of sugarcane which have in most regions almost completely replaced the extensive grasslands of the past.

The major perennial invasive aliens such as Lantana camara, Solanum mauritianum and Chromaleana odorata that tend to invade this site will have to be dealt with using conventional means.

The invasion of woody species will mostly be taken care of by the annual burning of portions of the grassland.

In areas with deep poor sandy soils which are readily colonized by the forest indicators, Melinis repens, Helichrysum kraussii Chrysanthemoides monilifera, Albizia adianthifolia should probably not be forced into becoming grasslands but be allowed to do what nature is clearly indicating is the natural option.

Gladiolus ecklonii growing in my grassland at Mount Moreland

Conclusion
Keep your plan simple if you want to be sure not to fail.
At the end of the day the final production will be determined by a combination of specialist knowledge, a good feel for the intricate workings of the natural environment, time, luck and the workings of mother nature. No man can plan such a rehabilitation project in an office in a far off place to give an exact result with absolute certainty. We are working with nature and anyone who says that they can give a precise result years down the line is either a charlatan or is God himself

Michael Hickman
Ecosystem Manager
Landscape Design Specialist


03.05.14


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