MEDIC PASTURE

The pod broadcasting method for pasture establishment

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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.
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.

YOU ARE HERE

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

The pod method of establishing medic and other annual legume pastures was developed by the International Centre for Agricultural Research in the Dry Areas (ICARDA) based at Aleppo, Syria.

The two basic documents are:

Dryland Pasture & Forage Legume Network News Issue No 8 September 1993 which describes the development of the medic pod harvester.

"Medic pasture establishment using pods sown into barley in the year prior to the pasture phase" - a thesis presented by Joyce Mitri. September 1994.

There is also a "Manual for the ICARDA pod sweeper" available from ICARDA or Faraj Allah Edelbi Company, Al Arkoub, Jebel al Ghazalat, Aleppo, Syria. Tel (963-21) 642695. This is available on this site too.

Farmers in the WANA region (for example at Tah in Syria and Le Kef in Tunisia) have been using some elements of the pod method but ICARDA deserves full credit for putting the concept together as a working alternative to the traditional Australian system of sowing with medic seed.

Since the development of the pod method by ICARDA, the technique has become an orphan without a sponsor. ICARDA, as a research organisation, has pulled out of medic research.

It rightly identified the problems of medic as practical implementation at the farm level not research in centres such as ICARDA.

The barriers to on farm adoption are a lack of appropriate farm machinery, a lack of grazing management skills and other farming problems.

Further research by ICARDA into adapted varieties and other "fine tuning" of the medic system is not justified until these basic farming problems have been overcome.

The existing ICARDA medic varieties are not used in the WANA region because there is no commercial seed production. The development of more cultivars would be a waste of resources. The withdrawal of ICARDA from medic work has left this excellent system of using pods as an alternative to seed without a sponsor.

Advantages of using pods

* Low cost.

The cost advantages of the pod method compared to the traditional sowing of medic with seed are considerable. Farmers can collect pods using the simple ICARDA machine instead of purchasing imported medic seed from Australia. Small farmers can use their own labour rather than cash (for seed) to obtain the pods.

The use of pod holding medic is another means of obtaining cheap pods. The ICARDA machine is suited to small farmers but pod holding medic is harvested using a standard cereal harvester. Larger farmers can harvest it easily and use the pods themselves or sell some to neighbors. This will reduce the cost of the long marketing chain.

There is no need to prepare a seed bed specially for medic pasture establishment. All the cost of seed bed preparation is already paid for by the cereal crop. For small farmers dependent on contractor this will be particularly important.

* Higher production.

As already mentioned in the chapter on traditional establishment using the Australian method of sowing seed the higher the seeding rate the denser the pasture and the greater the production early in the autumn and winter.

Farmers using seed will find these high seeding rates too expensive. Pods will cost less and higher rates can be used. The first year pasture will be more productive.

In the year that the medic pasture regenerates (the season after it has been sown on the cereal crop) it will germinate with the first rain. It will grow and produce feed earlier than a pasture sown from seed.

A seeded pasture will be sown a few weeks later after the ground has been cultivated and sown. This is under the best circumstances. If contractors are late or if the farmer gives priority to the cereal crop seeding of medic pasture is delayed further.

* No conflict with cereals.

The traditional method of establishing a medic pasture is to use using seed but there is a conflict for tractor time between sowing the medic pasture and the cereal crop.

Farmers will want to sow early to obtain early medic pasture production. They will also want to use tractor time to start preparing the ground for cereals. Late sowing of cereals will reduce yields. There is no conflict when the pod method is used.

Unfortunately experimental results from the WANA region have largely ignored the time constraint faced by farmers. They have sown their experimental plots at the ideal time and obtained results that have little relevance to real farms.

Brad Nutt and Angelo Loi from the Western Australian Department of Agriculture and Food have conducted experiments that recognise the fact that farmers will give preference to sowing their cereal crops rather than their pastures. The experiments were conducted with another pasture legume, serradella, but the experiments provide valuable information on the pod sowing method in general. Hopefully other experiments will be conducted with medic cultivars.

The first experiment compared 50 kg of pods broadcast into cereal stubble in January (mid summer or July in the northern hemisphere) with 10 kg of seed sown in early winter.

Serradella Cultivar

Dry matter yield in spring 2009 (kg/ha)

Pod yield (kg/ha)

Summer broadcast pods

Early winter sown seed

Summer broadcast pods

Early winter sown seed

Erica/ Margurita

2013

208

556

315

87GEH72

3026

290

1384

893

Santorini

916

109

459

710

The second experiment looked at different sowing dates during the summer, autumn and early winter to compare the breakdown of the hard seed character.

Serradella cultivar

Initial germination (%)

Plant establishment at June 15th (mid winter) 2009 as % of the seed numbers sown on the dates sown. The seed numbers were contained in machine harvested pods.

Feb. 13 (August in northern hemisphere)

March 19 (equivalent to September)

April 16 (equivalent to October)

May 19 (equivalent to November)

Erica

18

63

58

37

7

Margurita

21

77

61

40

9

87GEH72

8

75

50

33

3

Santorini

12

13

7

5

7

These experiments provide an alternative model to the ICARDA work where pods were broadcast during the autumn of the previous season. If the results apply equally well to medic there are some considerable advantages to be obtained from summer broadcasting.

+ The cereal stubble can be grazed with sheep without any concerns about them eating the pods. Once the stubble has been grazed the pods can be broadcast and no more grazing takes place until the pasture germinates and grows.

+ If medic hard seed break down shows a similar pattern to Serradella and summer broadcasting produces plant establishment of 60 to 75% the farmer can harvest the pods and broadcast them in the same season as the pasture produces grazing. With the ICARDA model the pods are harvested in summer, broadcast in autumn, germinate in the following autumn and produce a pasture then. The costs incurred in the first summer are not rewarded for 18 months in the form of green pasture. With summer broadcasting the time is reduced by one year.

+ If this is combined with the use of pod holding medic one can see the potential for a very low cost- high output system. The pods are harvested using a conventional cereal harvested in summer and them broadcast soon afterwards onto cereals stubbles.

* Better adapted varieties.

If the medic pods are harvested from a good local medic pasture they will consist of the cultivars originally sown and gradually more and more of the adapted local ecotypes.

This mix will be better adapted to the local environment than imported seed. Local farmers' pastures will begin at a point of greater local adaptation than if they used a mixture of imported seed.

* New rotations.

The Zaghouan 4 rotation is dependent on the pod method of establishment.

A cultivated fallow is used before the cereal crop. The fallow kills the medic pasture and prevents seed production.

The reserves of seed in the soil are destroyed and the pasture will not regenerate.

The low cost of establishment using pods and the elimination of the conflict with cereals for autumn time means that re-establishment of medic on a regular three or four year cycle becomes a feasible and profitable idea.

With the traditional seeding method the higher cost of establishment is justified by spreading it over many years.

The cereal-medic rotation can continue for many years without re-seeding. In parts of South Australia it has been used for 50 year without re-seeding. Under these circumstances the cost is almost negligible.

* Cultivation problems postponed.

The Zaghouan rotations postpone the problem of introducing shallow cultivation.

The medic pasture is fallowed in the spring before the cereal crop and medic will need to be re-sown. Burying the seed pods with deep ploughing does not matter. This part of the rotation does not depend on medic regeneration.

In the long term shallow cultivation will prove to be more cost effective but in the short term it greatly simplifies the introduction of medic if existing machinery is used. For small farmers employing a contractor there may be no choice if the contractor does not have equipment designed for shallow cultivation.

As we pointed out in Medic overview Libya, Iraq and Jordan imported the complete medic system including the appropriate farm machinery.

Other countries in the WANA region used a fragmented medic system based mainly on imported medic seed that ignored farm machinery and practical on farm advice. Libya, Iraq and Jordan have stopped importing the machinery suited to shallow cultivation.

The other countries are unlikely to import shallow cultivation equipment as they have moved into a new policy of commercial agriculture where such decisions are left to the market. The market for farm machinery is dominated by the European and US manufacturers who find it more convenient to supply the WANA market with their European and US designs than the Australian designs which they produce in their Australia.

The farmer - as the customer in the market - finds the package of medic pasture and shallow cultivation daunting. If he is forced to change to shallow cultivation as part of the medic package there is another investment needed, another skill to be learnt, another risk to be taken.

We will show that shallow cultivation is profitable in its own right whether medic, vetch or grain legumes are used in the rotation. If the shallow cultivation investment can be separated off from the medic pasture decision it will appear less daunting and complex for the farmer.

For small farmers dependent on contractors it is particularly important as they cannot change the contractors' machinery.


Disadvantages of using pods

* Mechanical harvesting of pods.

The pod harvester developed by ICARDA is ideal for small farmers. It is used by two or three people, can be pulled by a donkey or even a small tractor. Pod harvesting

Most small farmers could comfortably harvest all the pods they need for a few hectares of medic in a few days.

On a larger scale of farming a larger machine is required. These exist in Australia (separate from the suction harvester and thresher for seed harvesting) but have not been imported into the WANA region. Larger farmers will probably find it more economical to use team of small machines or purchase surplus pods from small farmers.

The use of pod holding cultivars of medic will eliminate many to these problems,

* Mechanical sowing of pods.

The medic pods must be broadcast by hand. There is no machine currently available for broadcasting pods. It may be possible to adapt air seeders for pods but this has not been done yet. In any case few air seeders exist in the WANA region.

Hand broadcasting is not a problem for small farmers only large ones.


Harvesting the pods


This is the first stage of the pod method because there is currently no market for purchasing medic pods.

One may arise in the future but it will be difficult to judge the quality of pods and it may be confined to an exchange between neighbors. With the seed method most farmers will buy seed as seed production tends to be a specialist enterprise.

Quote from the ICARDA Newsletter. No 8 September 1993

The medic sweeper

Farmers have not tried to harvest pods in the past simply because it was too time consuming and difficult.

The medic pod sweeper makes the task manageable. The medic pod sweeper, which has no engine, is pushed by hand, like a push lawn mower. A brush assembly, rotating about a horizontal axis against the direction of travel, sweeps light materials from the soil surface into a removable catching basket. When
attention is paid to land preparation the sweeper can collect most of the pods in a single pass.

If the soil surface is uneven or rocky, recovery is lower and more trips over the soil are required to sweep up the pods. The best technique is to sow long rows of promising medic ecotypes followed by rolling, so the sweeper can straddle this row and brushes up the pods when they are mature.

Land preparation is the most important factor affecting efficiency of harvesting. Pod harvester

Scott Christiansen.

The step by step process is as follows:

* A medic pasture is established using the traditional seeding method and with a suitable mixture of cultivars.

Care it taken to prepare a level seed bed and after seeding the land should be rolled if possible. Obviously using a scarifier, harrows and seeder fitted with small seed box will make this task easier. If these appropriate implements are not available farmers or research centres will have to improvise with the available machinery.

These foundation pastures could be established on government research centres, demonstration or state farms.

* The medic pasture is grazed during winter to control weeds.

* In the spring the pasture is allowed to flower and produce seed without livestock grazing.

* In early summer the pods will mature and fall on the ground.

* The dry medic straw should be raked into rows leaving the pods on the ground.

* The pods are then collected using the ICARDA sweeper.

* Medic straw is removed from the pods in the catching basket. Some simple cleaning of the straw and dust from the pods is desirable. Tossing the material in the air on a windy day will achieve reasonable separation.

* The medic pods are put in sacks and stored until the following autumn or winter.

In organisational terms the pods could be harvested by farmers themselves from a research centre or other government farms for a small fee to cover the hire of the sweeper.

In future years farmers could hire the machines and harvest pods from their own fields.

Hopefully over time there will be a market in pods and farmers will have the option of purchasing them or harvesting their own.

Pods can be threshed to produce seed although this is a difficult task as the pods are tough and hard to break open. There are some instances where seed has an advantage. Farmers could thresh pods for this market.


Broadcasting the pods


* Time of sowing.

In the autumn the fallow land is sown to cereals in the usual manner (cereal-fallow rotation).

In the ICARDA experiment the pods were broadcast on the cultivated seed bed prior to the sowing of the cereal. This can be difficult for farmers with limited labour resources and broadcasting the pods after sowing the cereals is more practical on many farms.

The work conducted in Western Australia with Serradella indicates that broadcasting in summer may be just as good.

After the cereals have been sown there is not such pressure on labour resources. Pod sowing is labour intensive.

* Method of sowing.

At present pods are hand broadcast. This is a tedious job. It is more difficult than broadcasting seed. The pods do not throw as well.

Larger amounts need to be broadcast. It may be possible to use small hand operated machines for this task as mentioned in the chapter on establishment using seed.

Even with these difficulties the broadcasting of pods should not be an insuperable burden.

* Sowing rate.

The ICARDA work used various seeding rates up to 300 kg of pods per ha.

We do not recommend a seeding rate measured in kg per ha.

We suggest that farmers adopt the same techniques as they would for the grazing of dry medic pasture in summer.

This is what the pod method is imitating. Farmers should broadcast an area with pods and then sample it using the same methods outlined in Grazing dry medic pods

However farmers will need a guide to how much weight of pods they should collect. The ICARDA work
conducted by Mitri showed that 200 to 300 kg per ha of pods produced a good density of medic plants.

The objective is to achieve a future pasture with at least 250 medic plants per square metre. This will require 500 to 750 seeds to be sown per square metre over the cereal crop. The reason for the high rate is that a large proportion of the seeds are hard. That is they will germinate over a number of years.

Some pods will be eaten by sheep and some will be removed by ants.

The pods are collected from the sample area, the pods are opened and the seeds counted.

This sounds a time consuming job but over a relatively short period farmers will learn to judge the sowing density and not require more than a few counts.

* The fate of the pods in winter.

After the pods have been broadcast over the cereal crop some medic seed will germinate when it rains.

Generally the germination rate will be extremely low. The pods were harvested in early summer. They were stored in sacks in a shed. There has not been the heating and cooling that occurs when pods are left on the exposed surface of the soil. This heating and cooling cracks the hard seed coat and allowing water to penetrate and germinate the seed.

The percentage of hard seed also depends on the variety. ICARDA found that only 5% germinated in the first winter.

These medic plants will grow in the cereal crop.

They will germinate late if the pods were broadcast after sowing the cereals. They will provide insignificant competition with the cereals. They will be killed if a herbicide is used for broad leafed weed control.

* The fate of the pods in summer and autumn.

During the summer the pods will remain near the surface of the soil in the cereal residues.

Care should be taken not to overgraze the stubble. Sheep will eat the pods on the surface. They will also dig pods out of the ground that are partially buried.

The heating and cooling of the soil in summer will cause the breakdown of the hard seed coat of many seeds in the pods. The percentage will vary with the variety but at least one third should break down and perhaps as much as a half of the seed in the pods.

In autumn these medic seeds that have become "soft" by the heating and cooling will germinate and form a medic pasture.

The remaining hard seeds will stay in the ground. Their hard seed coat will be broken down in the following summer.

This is still uncharted territory but could form the basis for the Zaghouan 5 rotation.

Fate of hard seed.

The chart below takes the seed for Barrel medic cultivar Paraggio through three possible systems.

Spring

Summer

Autumn

Summer

Autumn

Classic medic- cereal rotation

Seed in pods more than 95% hard
Summer breakdown of hard seed coat.
30% of seed germinate and are killed when cereal crop sown. 70% carryover.
Summer breakdown of hard seed coat.
Pasture germinates from medic seeds that are now soft.

Establishment using pods

Seed in pods more than 95% hard
Pods harvested early.
Broadcast over sown cereal crop. Germination low - perhaps 5%
Summer breakdown of hard seed coat.
Pasture germinates from medic seeds that are now soft.

Establishment of medic on the parcour

Seed in pods more than 95% hard
Pods harvested late
Perhaps 30% of the seed will germinate and form a pasture.

The medic pasture germinates

The seeds that have softened will germinate and form a pasture. This germination will be some weeks earlier than a medic pasture sown from seed in a traditional seed bed. Once the medic plants have germinated the pasture is managed in the normal way.