MEDIC PASTURE 

Establishment of the medic with seed.


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CHAPTER HEADING

SUMMARY OF CONTENTS

The first stage in convincing farmers to adopted medic pasture is to produce a simple budget. This shows the changes in costs and returns when medic is grown and the increase in profit. Some sample budget forms are provided.
If the extremes of over-grazing and under-grazing can be avoided the medic pasture has a much greater chance of success. Some simple planning to provide a rough balance between the area of proposed medic pasture and the number of sheep will make grazing management much more straightforward.

You are here

The traditional method of medic pasture establishment in the WANA region over the last 25 years and in Australia for 80 years has been to sow medic seed into a well prepared seedbed. Medic seed can be costly and seedbed preparation and sowing is difficult for small farmers who lack the proper equipment.
Establishing medic pasture using pods is an innovation that offers many potential benefits particularly for small farmers. The method was first developed by ICARDA in Syria in the 1990's and now forms the basis of the Zaghouan rotation in Tunisia. It potential in the WANA region is considerable.
The parcour or rough grazing land occupies more than half of the cereal zone in the WANA region. Pasture establishment using seed has been difficult but pods may be a better option.
Grazing the green medic pasture is vital in make a profit, to control weeds and produce ample supplies of pods for future years. Farmers in the WANA region have developed innovations that take their grazing management to higher levels of efficiency than those achieved in Australia.
Pods provide a valuable feed supply in summer for sheep and are needed for the regeneration of the pasture in future years. Farmers must find a balance.
Measuring the pods is an important part of grazing management. We have made a separate topic so it can be printed and used as an extension guide for farmers.
The medic pasture has completed its first year. The pasture regenerates with the autumn rains. Farmers must decide whether to cultivate the land for cereals (the classic medic - cereal rotation) or leave it for another year or more. The options are discussed.
Making hay from medic is not as simple as it may seem. This chapter discusses the options and innovative rotations for medic hay production.
Turning the medic pasture into profits is the objective. This chapter shows how live-weights are increased, death rates reduced and lambing percentages increased. The new flock structure is more efficient and produces greater returns.
A check list of possible failures and what to do about them.

 

FOUR COMMON ROTATION ON THE GROUND IN THE WANA REGION

SEASON

ROTATIONS

CEREAL - FALLOW

CEREAL - MEDIC
( Traditional rotation)

CEREAL - VETCH

CEREAL - GRAIN
LEGUME.

AUTUMN

Cereal crop sown

Cereal crop sown

Cereal crop sown

Cereal crop sown

WINTER

Cereal crop grows

Cereal crop grows

Cereal crop grows

Cereal crop grows

SPRING

Cereal crop matures

Cereal crop matures

Cereal crop matures

Cereal crop matures

SUMMER

Cereal crop harvested
Stubble grazed by livestock

Cereal crop harvested
Stubble grazed by livestock

Cereal crop harvested
Stubble grazed by livestock

Cereal crop harvested
Stubble grazed by livestock

AUTUMN

Weeds germinate naturally

Medic regenerates from seed
produced 18 months earlier.
No cultivation of the land required.

Land cultivated and sown to vetch or similar forage legumes.

Land cultivated and sown to grain legume such as lentils or
chick peas.

WINTER

Weeds grazed. Low stocking rate.

Medic pasture grazed. High stocking rate.

Grazed or more often left for hay.

Grain legumes grow.

SPRING

Land cultivated for fallow

Medic grazed. Pods produced for future regeneration.

Cut for hay.

Grain legumes mature.

SUMMER

Bare soil vulnerable to erosion.

Pods and stubble grazed.

Stubble grazed.

Grain legumes harvested.

Stubble grazed.

AUTUMN

Cereal cycle begins again.

Cereal cycle begins again

Cereal cycle begins again

Cereal cycle begins again

Introduction

        When I began farming in the mid 1960s one of the first difficulties I had to overcome was establishing annual legume pastures.

They had never been grown on our farm in South Australia before. I had the standard set of equipment found on most Australian farms at that time. I had a scarifier for shallow cultivation. I had some harrows, heavy and light and I had a standard Australian cereal seeder. The cereal seeder had four rows of tines, a box for cereal seed and a box for fertiliser.

        The first stage was to burn the remains of the cereal stubble from the previous year.

This had been grazed by sheep but enough stubble remained to block the scarifier, harrows and seeder.

After the first rains in autumn I cultivated the land with the scarifier to a depth of 7 cm. I then harrowed it as a separate operation but this could have been done together with the scarifying.

I then sowed the legume seed using the cereal seeder.

        Modern farm machinery has become bigger and more complex but the difficulties as far as sowing legumes seeds remain much the same.

I could not sow the annual legume seeds through the cereal seed box. The mechanism for cereal seed was too coarse and would not deliver the low seeding rate of 12 to 15 kg per ha. of legume seed.

Sowing through the cereal box delivered the legume seed through a tube into a "boot" behind a sowing tine. This placed the seed at a depth of about 4 to 6 cm. below the surface. This depth was perfect for cereals but much too deep for small legume seed. They would never germinate from that depth.

        For the first year I used the fertiliser box.

I placed phosphate fertiliser in the box. I then placed legume seed over it and mixed the two together. I placed more fertiliser in the box and mixed again.

I disconnected the tubes which delivered the fertiliser (and the cereal seed) into the boot. I then tied the tubes to the back of the seeder. The fertiliser and seed were scattered on the surface.

The method worked reasonably well but much of the seed was still sown too deep. It was scattered on the surface of the ridges and furrows behind the seeder at the point where the furrows were being closed. Seed that bounced down into the furrow was too deep. It did not germinate and was wasted.

    My next improvement was to buy a special small seeds box. This was an attachment to the cereal seeder - a third box bolted on the back behind the fertiliser box. It was specially designed to handle low seeding rates for small seeds such as annual legumes and lucerne.

It still required modification as the standard tubes (or without tubes) delivered the seed at the back of the seeder where the furrows were closing. This meant that seed that bounced into the furrows was too deep (as above). 

I found that neighbouring farmers had developed curved tubes of black polythene pipe that delivered the legume seed further back into the centre of the light harrows that were dragged behind the seeder.

The harrows closed the ridges and furrow and produced a level seedbed.

Putting the seeds into the centre of the harrow and lightly stirring them proved ideal. The results were excellent.

The tubes feeding the medic seed into the light covering harrows is illustrated in Training Kit 2.3

Using the Australian method in the WANA region

    Libya, Iraq and Jordan all imported the medic system as a complete package of seed, equipment and expertise from Australia.

They had much greater success compared to other WANA countries that imported a fragmented medic package consisting of just seed and some theoretical knowledge. 

These three countries had scarifiers, seeders and harrows. They had Australian farmer to demonstrate the technique. They could prepare a level seedbed with few clods as I had done in Australia with a single passage over the ground with each implement.

The medic and other legume seeds were then sown using the cereal seeder. In Iraq and Jordan they were fitted with the special small seeds box and were most effective.

In Libya the small seeds box had been forgotten and improvised methods such as my mixing with fertiliser had to be used. Medic pasture establishment was generally excellent.

In the other WANA countries the problems were enormous due to a lack of suitable farm machinery and it is a credit to the persistence of extension agents and farmers that medic was ever established.

The seed bed was prepared using ploughs and chisels used for cereals. These produced a deep uneven seed beds with many clods. Many operations with tandem discs, cultivators and harrows followed to break down the clods and level the seed bed.

In Algeria on a medic consultancy in the late 1980s we found that up to 17 separate passages over the ground had been used to prepare and seed a medic pasture. The average was more than half a dozen. The cost and the use of precious autumn time was considerable.

The cereal seeders on most farms proved unsuitable.

They were not able to handle the small legume seeds.

They did not sow fertiliser. Farmers had to improvise.

The most successful method was hand broadcasting and light harrowing.


GETTING STARTED

  Training Kit No 2.2 describes the resources need to establish a medic pasture.

 Training Kit No 2.3 the seed bed preparation and sowing. 

  The cereal stubble

    Medic and other annual legume pastures will normally be sown into the cereal stubble residues in autumn.

In the WANA region the cereal stubbles are heavily grazed in summer.

It is unlikely that the straw residues will be sufficient to block implements (scarifier and harrows) used in the preparation of the seed bed. Burning should not be necessary.

If heavy residues remain after grazing in summer they can be burnt. Burning stubble is not recommended as it destroys valuable organic matter that will improve soil structure but this is an exception. Medic pasture is only established once.

The grazed medic will return more organic matter to the soil over a few months than the stubble residue that was burnt. Medic will improve the soil structure considerably. A single burning of the stubble in the establishment phase of the medic pasture is not important in the long term.

On the other hand most of the common cultivators used in the WANA region have not been designed to handle straw. In  Buyer's guide to scarifiers we describe the design of the scarifier.

The ability of the scarifier to allow straw to pass through without blocking depends mainly on the number of rows. A scarifier with only two rows (common in Tunisia) will block with even light stubble residues. A scarifier with three or four rows should be able to handle the straw after heavy grazing without blocking.

With the cereal-fallow rotation any straw that is not eaten in summer is left on the ground and rots during the winter weedy fallow or is ploughed into the soil during spring cultivated fallow.

    After the medic has been established from seed and has become part of a medic-cereal rotation, the medic will regenerate in the cereal stubble without re-seeding. Again any straw residue will rot down over the winter and spring. With the greater nitrogen availability under medic the rate of straw breakdown will be considerably greater than with the fallow-cereal rotation.

It can be seen that excessive straw residues are not a long-term cultivation problem with the cereal-medic rotation.

It is only in the first year of medic seeding that there can be a problem with excess straw.

To purchase a scarifier with superior straw handling capacity for the first (and hopefully only) establishment year would not be justified.

If the scarifier is blocking badly in the autumn it is usually too late to burn.

Anticipating the problem by heavy grazing or burning is certainly the best option.

Alternatively a tandem disc can be used to chop the straw but time is wasted as a scarifier is need afterwards to level the seedbed.

    Alternatives:

    Farmers may be able to find a contractor with such a scarifier with four or five rows of tines who will do the cultivating work.

    Farmers may be able to rake the excess straw and remove it.

    Another trick that can work is to reduce cultivating speed for the scarifier. The straw will work through a scarifier better at low speed.

    The tandem disc will handle the cultivation and the straw. The problem is that a seed bed prepared with a tandem disc is too rough to seed with small legume seeds.

Harrowing is out of the question as the harrows will block with straw if the scarifier blocked.

One way (not ideal by any means) is to cultivate with the tandem discs closed (that is the transport position). This does not create such a rough seed bed. It is not very effective in cultivating either. The land will need to be cultivated two or more times in different directions. This costs time and money but may be the only means available,

    Cultivating stubble residues in autumn is not just a problem for medic pasture establishment but for vetch and grain legumes.

If deep ploughing is used the straw is normally buried but if shallow cultivation is used the farmer needs to consider the design of the scarifier and its ability to handle straw.

Scarifiers with four rows of tines or more can handle considerable amounts of straw and large quantities are unlikely in the WANA region for many decades. Leaving straw on the surface with a scarifier is better for the long term organic matter content of the soil than burying it to a depth of 20 cm.

    Preparing the seed bed.

        The ideal method remains the scarifier. This implement is described in detail (see Buyer's guide to scarifiers). It is essentially a heavy-duty cultivator that can work hard ground to a shallow depth.

        Unfortunately scarifiers are still not common in the WANA region.

Instead of preparing a seed bed with cereal equipment such as ploughs and chisels we recommend that light cultivators and tandem disc are used at a shallow depth until scarifiers have been purchased. These implements have poor penetration of hard ground but produce fewer clods than the deep cultivating implements.

They need to be worked at least twice at right angles to cut off all the weeds. This is more expensive than using the correct implement (the scarifier) but is cheaper than deep ploughing and the many associated workings needed to break-down clods.

Harrowing will level the seed bed. This is particularly important if the tandem disc is used as it does not level the ground.

        Cultivation should start after the first good autumn rains.

Cultivating the soil dry may be possible on some light textured soil (but creates a dangerous erosion risk) but on heavier soils is not a good idea.

It is doubtful that the cultivator or tandem disc will penetrate hard, dry ground. Even the specially designed scarifier will find it tough.

The cost is high in terms of tractor fuel and wear of points. The hard clods produced are difficult to break down.

The secret of preparing a seedbed with few large clods is not an elaborate process of breaking clods down but trying to avoid creating clods with the first cultivation.

        Cultivating dry ground is a waste because the weeds have not germinated. The ground will need to be cultivated again to kill weeds.

   Seeding rate.

        The seeding rate is essentially an economic decision.

Sow what you can afford.

Seeding rates for medic and other annual legume pastures up to perhaps 50 kg per ha. will improve the density of the pasture and the early growth.

In spite of the fact that early productivity is valuable for sheep production in winter, commercial farmers will not invest in such a large amount of money in seed. They will consider the risks too high.

        In the real world seeding rates of between 15 to 30 kg per ha. are used in the WANA region. In Australia seeding rates are 15 kg and less.

Seed in Australia is slightly cheaper but returns from sheep are much lower.

In the WANA region extension agents have recommended seeding rates nearer 30 kg per ha. 

The reason for this advice has been the generally poor seed beds and seeding methods.

It is economically sound in the short term to increase seeding rates to 30 kg/ha rather than invest in the correct implements for seed bed preparation and seeding. In the longer term it is money wasted.

The  correct implements will be needed for cereals as well as for further medic establishment. It is easy to show that an extra 15 kg/ha of medic seed over 100 ha will cost less than purchasing a small linkage scarifier.

    Governments in the WANA region that did not import the complete medic package have invested heavily in seed production.

One reason is the heavy seed usage. Seed usage could be reduced by better implements that prepare better seed beds.

The same implements would have been used for the cereal crop. Medic would have regenerated better after the cereals and would not need to be re-seeded so frequently.

The use of pod holding medic grown and harvested on the farm or purchased from a neighbor will be considerably cheaper than seed purchased from a merchant. It may be profitable to use higher rates with this cheap seed,

    Selecting the cultivars

        More information on cultivars is provided in technical backup and in Fodders for the Near East: Annual Medic Pasture, By Brian and Lynne Chatterton FAO 1989. In spite of the poor editing and production by FAO this is still a useful book on medic.

    For a complete guide to cultivar selection refer to chapter:  What cultivar of medic for the cereal zone?

        In the WANA region the selection process is quite different from Australia.

In Australia there are no local ecotypes. Farmers need to select a seed mixture that will exploit the environment (both natural and managed) to the optimum degree and establish a productive pasture.

While the same long-term objective applies in the WANA region any medic mixture sown will gradually change as local ecotypes re-establish themselves. Once the environment for medic is re-established on farms these local ecotypes that have been suppressed by the fallow and deep ploughing will multiple. They will form an important part of the pasture mixture. Over a series of regeneration cycles they will become dominant.

    We have observed the change-over process in action in Algeria.

A farm at El Khemis that survived the FAO medic project in the 1970s had sown Jemalong, an Australian medic cultivar with a distinctive leaf mark. Over the next 10 years with each regeneration of the medic pasture more and more local medic was present until finally the Jemalong almost disappeared.

    The significance of this process is that gaps or failings in the original sown medic mix will, over time, be filled by local ecotypes.

The author and Adam Lakhdar examining plots of selections of cold tolerant medic on the high plateau of Algeria. As far as I know these seed lines and research reports have been lost. This photo is the only record of the work done by the Algerian Ministry of Agriculture.

This is most important in cold regions such as northern Iraq, northern Syria and the high plateau of Algeria.

Most Australia cultivars are not particularly cold resistant and are sometimes damaged by winter frost.

They will re-grow but pasture production is reduced and the feed output is below the optimum.

Local cultivars have been selected by research institutions that are more frost resistant but there is no commercial seed production of these frost resistant cultivars.

Farmers in these cold regions can sow sub-optimal mixtures in the knowledge that over a few regeneration cycles local frost-resistant ecotypes will become dominant and fill the gaps in the original seed mix.

The output of pasture may be less than optimal for the first few years but even an average medic pasture is many times more productive than the weedy fallow it replaces.

    Seed price

    Not all medic and other annual legume seed is the same price.

The choice of cultivar will also be determined by the price. If the best cultivar is expensive it can be replaced in part by a cheaper cultivar in the knowledge that a few regeneration cycles will establish a new balance.

Those cultivars or ecotypes more suited to the environment will produce more seed and will become the dominant part of the pasture.

      Seed size

    As well as selecting cultivars that are well suited to the environment (soils and climate) the farmer should consider seed size.

The cultivars with a large seed (the Snail group) are easier to establish under conditions that are not ideal.

They will establish better on poor seed beds and will germinate from a greater depth.

They should not however be sown alone as they grow more erect and are therefore not as good grazing plants.

The large seeds are associated with large pods. These are easily eaten by sheep and there is a danger of over-grazing the dry pods.


These snail medic pods look dramatic but they are easily eaten by sheep and seed mixtures should contain small cultivars with small pods. 

Medic variety

Seed weight

Snail medic

15.0 mg.

Gama medic

6.3 mg.

Barrel medic

2.9 to 8.9 mg. depending on cultivar

Disc medic

4.2 mg.

Burr medic

2.7 mg.

Strand medic 

2.4 mg.

It can be seen from the above that Snail medic seeds are more than twice as big as Gama medic and 5 or more times bigger than other varieties.

    Sowing depth and methods  

    Sowing depth for medic is an academic point as there are few seeding machines that can accurately sow the seed to a specified depth.

The most important point is to avoid deep sowing.

Medic seed is small (see above) and if the seed is sown deeper than 1 cm it will not emerge.

The larger seeds of the Snail group of medics are an exception and they can withstand sowing to a depth of 2 cm.

The reality is that medic seeds are broadcast on the surface and mixed with the soil in the hope that the seed is not buried to any greater depth than 1 to 2 cm.
 

    + Small seed box

    The ideal method is the small seed box attached to a cereal seeder ( see Training Kit No 2.3) but they are not common in the WANA region.

It is doubtful whether cereal seeders will be purchased for medic sowing alone but if these seeders are purchased for cereals it is only a small extra cost to add the small seed box and is worthwhile.

The cereal box is designed for the much larger cereal seeds and heavier seeding rates.

The extra small seed box handles medic, clover, lucerne, and other small seeds and rates from 2 to 50 kg per ha. Even this seeder box needs some modification.

The manufacturers fit tubes to the small seed box that drop the seeds directly behind the tines where the earth is still closing when the implement is moving.

Farmers in Australia have fitted longer curved tubes made from black polythene pipe. These tubes take the medic seeds and drop them in the light covering harrows where they will not be buried to an excessive depth.

    + Fertiliser spreader

    An alternative is to improvise using fertiliser spreading machines.

Spinners are totally unsuitable as the medic seed is not thrown very far.

Machines that drop the fertiliser on the ground can be used.

If the cereal seeder is used take the tubes out of the boots and tie them toward the back so the fertiliser and seed is dropped into the harrows.

A mixture of simple phosphate and seed can be made in the box.

Farmers need to be aware of the dangers of burying the seed too deep if the seed and fertiliser is dropped on ridges and furrows that are then closed over using light harrows.

The cereal seeder with a fertiliser box can be used in the same way. The seeder can be use to drop the seed and fertiliser mixture on the soil or the tubes can be removes and tied behind to prevent excessively deep placement.

    + Hand broadcasting

Hand-broadcasting has proved to be a very successful method in the WANA region.

Farmers have hand-broadcasting skills and the success rate is usually good.

The seed bed is prepared.

The seed is broadcast and then covered with light harrows or if these are not available improvised harrows made from thorn bushes.

    In Morocco the quality of hand-broadcasting was improved by leaving a regular pattern of wheel tracks from the last harrowing. The farmers followed these and broadcast to their width.

    + Hand spinners

    There are a number of hand-operated spinners costing about Euro 30 that are carried by farmers (strapped onto their chest).

These may be more productive than hand-broadcasting. They are certainly worth experimenting with.

There are also more expensive (about Euro 100) hand carts with spinners. They may be useful also.

   Fertiliser

    The standard recommendation is 100 kg per ha. of triple phosphate. See  Fertilisers .

Over time farmers will need to fine tune their fertiliser rates but as virtually no phosphate is current applied to pasture this is a good starting point.

The fertiliser can be applied at seeding or before if that is more convenient.

For example if the medic seed in hand broadcast it may be more convenient to apply the phosphate to the dry ground before the seed bed is prepared.

    Time of sowing

    Of course the ideal is to sow the medic:

    + into a well prepared seed bed

    + that is free from weeds

    + that has adequate moisture

    + as early as possible (that is when the soil still retains the heat of summer).

    This ideal rarely occurs on farms.

It happens frequently on research centres as they have large resources of machinery and labour.

For farmers it is a question of trade-offs.

Seed bed preparation starts in the autumn after the first good rain.

    Trade-off ONE - better seedbed but later sowing.  

Better seed bed preparation will take time and money.

Germination will be better. The medic pasture will be dense and productive.

Seeding rates can be lower - some costs are saved.

Late sowing will delay germination and growth in autumn and production will be lost.

Extremely late sowing may mean the medic does not flower and produce seed in the spring before the summer drought and the pasture fails to regenerate in future years.

    Trade-off TWO - early sowing but poor seedbed.

Early seed bed preparation and seeding will produce a more productive medic pasture.

The seed will germinate when the ground is warm.

The medic will grow before the period of short days in winter. The medic will produce more seed in the spring.

Seeding rates may need to be increased to compensate for rough seed bed.

    Farmers have the seed bed and sowing of cereals to consider.

Giving priority to medic will delay the cereals. Yield and profits may be reduced. The argument in favour of medic is that it is only established once.

If the medic is well established it should regenerate year after year. There will not be a conflict of priorities in future years. This is unlike vetch or grain legume where the conflict for priority in the autumn occurs every year.

    Trade-off TWO is the best option. That is:

    + priority to medic,

    + early seeding even if seed bed preparation and weed control is not optimal,

    + heavier seeding rate to compensate.

Practical details

    Wait for rain

                            Do not cultivate the ground dry. Wait for the first good rain in autumn.

In most of the cereal zone and high rainfall zone of WANA the opening of the season begins after a fall of about 20 mm of rain over a few days.

In the part of the cereal zone with less than 350 mm average annual rainfall and on light textured soils farmers are content (or have learnt to live with!) with less rain to start the season.

After the rain has fallen resist the temptation to start cultivating immediately.

If the ground is still warm the weeds should germinate quickly. It is better to start cultivating a week or even ten days after the rain. Cultivation will kill the weed seedlings.

    Cultivation

Cultivate the land with a scarifier.

Use a depth of 7 cm.

Drag a harrow behind the scarifier.

This should produce a reasonable seedbed in a single operation.

If it is still too rough harrow again at a faster speed. This should be done as soon as possible while the clods are still moist.

If a cereal seeder is available with small seed box it may be possible to scarify the land and sow the seed in a single operation.

    Seeding

 Assuming that no seeder is available with a small seed box, broadcast the medic seed by hand.

Alternatively use a fertiliser spreader or the cereal seeder with a seed-fertiliser mix.

In either case the mixture of medic seed and fertiliser is dropped on the surface. The land should should then be harrowed using a light harrow.

If light harrows are not available improvise with reinforcing mesh or thorn bushes.

Undersowing cereals with medic seed

Undersowing a cereal crop with legume pasture is an old technique that was used in the northern temperate regions years ago. Over the last fifty years legume pastures (mainly white clover) have gone out of fashion because of cheap nitrogen fertiliser and the high subsidised price of milk and meat.

The legume seed (usually clover) was sown with the cereal seed although at a shallow depth. It germinated under the cereal crop. After the cereal harvest the clover continued to grow with summer rain and provide a pasture for livestock.

The objective was to save time and money by not preparing a seed bed and sowing seed for the clover as a separate operation.

Using undersowing in WANA

The technique is not effective in the WANA region and other areas with a Mediterranean climate.

The pattern of rainfall is a dry summer. The legume struggles to survive under the cereal crop. Competition for light and water means that it rarely thrives.

Herbicides are now commonly used to control broad-leafed weeds. These will also control the legumes.

If the clover or medic does survive under the cereal crop and produces seed it will be eaten by the sheep during the summer when they graze the cereal stubble.

The undersowing idea has been transformed into sowing medic pods. This is described in the next chapter.

Oversowing medic with cereals

This turns the concept on its head and the cereals are sown as a protection for the medic and are not intended as a crop to be harvested.

The idea is applicable to the marginal zone where it is often difficult to enforce grazing rights over pasture.

A very sparse cereals crop will qualify as a "crop" even if it is not harvested and provides protection for the medic in the first year.

The concept is discussed in some detail in the chapters on the Marginal Zone.