MEDIC PASTURE

How does your medic grow? 
 

Trouble shooting guide to medic pasture.

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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.
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.

YOU ARE HERE

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

  

* Poor density of medic plants in late autumn and early winter.
 

The density of medic plants in the autumn is most important for future productivity. A low density of 100 to 250 plants per sq. m. will be less productive in autumn and winter.

It will not catch up in the spring unless the season has above average rainfall.

Medium density of 500 to 1500 (depending also on the cultivar of medic) will produce three or more times the amount of pasture during autumn and winter. Spring output is also high.

A density up to 3,000 plants will be even more productive.

Poor density of seedlings in new pasture sown from seed.

Factors under management control.

+ Low initial seeding rate.

 Low seeding rates are often used because of the cost of medic seed. Seeding rates of 10 kg per ha will result in reasonable density of medic seedlings provided the seedbed is good and the medic is not sown too deep. Below 10 kg there will be some reduction in density. Establishment using seed

+ Poorly prepared seedbed with too many clods.

Medic seeds are small and need a well prepared seedbed. Poor seedbeds are usually the result of using unsuitable implements such as disc or mould board ploughs. A scarifier and harrows should produce a good shallow seedbed without too many clods. Poor seedbeds are a particular problem with low seeding rates. In the longer term increasing the seeding rate to over come the poor seed bed is an expensive solution to the problem. Good seed beds are not expensive if the appropriate implements are used.  Establishment using seed

 + Medic seed sown too deep.

  If medic seed is sown through a cereal seeder or mixed with the fertiliser in a cereal seeder it is easy to sow too deep. Seed must be sown at less than 2 cm. Broadcasting and gentle harrowing is the most practical means of seeding in most of the WANA region. Establishment using seed

 + Insect attack on young seedlings.

If insect attack is expected the seed can be treated with some insecticides. Otherwise the young seedlings should be sprayed.

Climatic factors - not under management control.

Germination of seed followed by drought resulting in death of seedlings.

Poor density of seedlings in new pasture sown from pods broadcast on previous cereal crop.

Factors under management control

+ Low initial seeding with pods.

Cost should not be a problem with pods. Low rates will be for some other reason. Establishment using pods

+ Low seed count in pods due to a dry spring in the season the pods were harvested.

 If the spring is dry the pods will produce less viable seed. This should be checked (checking the actual viability is difficult for a farmer but at least check the number of seeds and their apparent vigour) and adjust the seeding rate accordingly.

+ Unsuitable cultivar selected with low level of seed hardness. Excessive number of seeds germinate in cereal crop and not carried over to pasture.

 This is an exceptional problem where the pasture used as a source of pods has been sown from seed. An established pasture in a rotation will have plenty of medic with hard seed.

+ Pods harvested by sheep or ants during summer in large amounts.

Pods are in the top few cm of soil and can be dug out by sheep if grazing is excessive. If the medic pods are mainly snail which has a large pod this can be a problem. Small pods are much more difficult to dig out of the soil. Ants can be a local problem around ants' nests.

+ Insect attack on young seedlings

As above. Control with insecticide.

Climatic factors not under management control.

 +  Exceptionally cool summer and hard seed not broken down in pods.

 +  Germination of seed followed by drought resulting in death of seedlings.

Poor density of seedlings in regenerating pasture from reserves of seed in the soil.

Factors under management control

  Previous medic pasture with poor density of plants, too many weeds and poor pod production.

Previous medic pasture overgrazed in spring. Poor pod production or green pods eaten.

Unsuitable variety and cultivar sown. Long season medic sown in a low rainfall area. Pods have not formed before summer drought or seed production low.

Good pod production but cut for hay and pods removed.

Cultivation of medic pasture in spring for long fallow.

Good pods production and allowed to fall on ground but overgrazing of dry pods in summer.

The use of deep ploughing which buries the pods at any stage.

+ Insect attack on young seedlings.

Climatic factors not under management control

 

* What to do about it?  

    Poor density of medic and weed plants.

    This is the easiest problem to deal with. Good grazing management during winter and spring will allow the medic to grow and gradually cover all the ground. Even a density of 50 seedlings per sq. m. should produce a dense pasture by spring. Production will be lost in the short term but the pasture will be restored. It is important to try to identify the cause. If the cause is a controllable management factor it should be corrected. Grazing green medic

     Poor density of medic and high density of weeds.

        Unfortunately this is more common. The gap left by a poor density of medic seedlings is filled by weed plants. Managing the pasture back to quality will be difficult. On the parcour there may be few other options but on arable land farmers will need to decide whether to try to restore the pasture through grazing management or start again.

    Again a density of 50 to 100 seedlings per sq. m. is a useful point to consider the reseeding option. Above that density it should be possible to control weed competition by grazing. Of course the nature of the weed competition is important. Grasses and self sown cereals are easier to control by grazing than unpalatable broad leafed weeds.

    It is possible to spray the pasture with a low rate of hormone herbicide such as 2-4-D or MCPA. The low rate will not kill the medic but will increase the sugar content of the unpalatable weeds and make them more palatable for sheep. The effect on weeds of spraying and grazing can be dramatic. Given the inexperience of most WANA farmers with precise applications of herbicides this is not a feasible solution in most cases.

    Below 50 seedling there is a balance between cost and difficulty versus the chance of success. For example if the poor medic is due to a series of management problems related to sowing with seed such as unsuitable implements for seedbed preparation and poor sowing techniques there is little point in reseeding unless these failures are corrected. If on the other hand the failure can be attributed to climatic effects and management is good then reseeding would be worthwhile.

    It is most important that the medic pasture is not allowed to drift into a downward spiral. Poor seedling density continues through to the spring (because of strong weed competition) and pod production is low. Weed seeds contaminate the cereal crop. Regenerating medic is again poor. This is the scenario that led to the failure of many early medic pastures because farmers were not offered a way out. They were inexperienced in medic and not unnaturally pasture were not as good as expected. These poor pasture went down in quality rather than improved.

    The Zaghouan rotation provides the break to the downward spiral. The spring fallow will kill the medic but will kill the weeds too. The medic can be re-established from pods.

Poor growth of medic pasture

Factors under management control

Species and cultivar not suited to the climate or soil.

This can be a problem in cold regions where suitably resistant varieties are not available as commercial seed. Provided there are some resistant cultivars or ecotypes in the pasture the best option is to wait for them to become dominant over a few seasons.

Inadequate phosphate fertiliser.

Apply more fertiliser. Making sense of fertilisers

Trace element deficiency.

Apply trace elements.

Severe overgrazing.

 Reduce grazing.

Climatic factors.

+ Lack of rainfall.

+ Severe cold.

Pasture dominated by weeds in the spring.
 

    This was a common problem in the WANA region because of a mistaken belief that the best management for medic was to leave it ungrazed for the first year. Many good medic pasture were destroyed in a few months through this form of management. The grasses became dominant. They shaded the medic which was weakened and died.

Any medic that survived produced few pods. The pasture went into an immediate downward spiral. Many of the experiments on medic fail to show its true value as they include these pastures as "medic" when they should be discarded as "failed medic" or "medic overwhelmed by weeds."

What to do about it?

    There are a number of key questions:

Measure the density of medic plants.

A low density of less than 50 to 100 plant per sq. m. will favour re-establishment next autumn or fallow and use Zaghouan rotation.

Higher densities will favour restoration of the pasture through grazing management.

How much of the growing season is left?

If the pasture is cut for hay or heavily grazed will the medic still have time to flower and produce pods before the summer drought? If this is a reasonable expectation heavy grazing or hay to reduce the weed competition is a feasible solution.

What sort of weed competition?

If the weeds are palatable grasses and self sown cereals grazing is more likely to succeed. If the weeds are unpalatable broad leafed species the grazing option is less likely to succeed. The use of hormone herbicides to improve the sugar content of weeds is not recommended so late in the season.

What is the plan for next year?

If the plan is to grow cereals the weed seed will cause a reduction in yield. Destroying the weeds through cutting for hay, heavy grazing or fallow in a priority even if the medic suffers. If a Zaghouan rotation is practised and the next year is planned as pasture a different decision be be taken. Medic can be restored in stages over two and half years

Will re-establishment produce better results next time?

If the failure was climatic or through poor grazing management that is now understood a new start can be a good idea. If the failure was due to a lack of seed, a poor seed bed and poor seeding methods and these have not been corrected then there is no reason to believe that another attempt will produce better results.

    The Zaghouan rotation is an ideal method of starting will medic.

    Getting started

    The first stage is to harvest medic pods with a simple harvesting machine. The next is to broadcast the pods over a cereal crop. Details are provided in  Establishment using pods  This is a cheap and easy means of establishing a medic pasture.  

    Rotations

    Once the medic pasture has been established using pods it can be used in a number of rotations. Most common is the Zaghouan 4 rotation.

    Year one: medic regeneration from pods sown over cereal crop a year earlier.

    Year two: medic regeneration from pods produced in previous year.

    Year three: autumn and winter   -   medic regeneration from pods produced in previous two years.

                    spring          -            cultivated fallow.

    Year four: cereals with medic pods broadcast over it.

   How to use the Zaghouan 4 rotation?

     *  The Zaghouan 4 can be used as a transition rotation for small and large farmers.

    The medic establishment is cheap.

The life of the medic pasture is spread over 2.5 years. The annual cost is very low.

The destruction of the medic by fallowing in the third year is therefore not a high cost.

The cereal crop is grown on fallow. The yield is high as the fertility after 2.5 years of medic is high and weed control is good.

Farmers do not need to acquire new skills. Even existing deep ploughs can be used (not recommended but a reasonable transition).

    As farmers acquire more grazing management skills and purchase the appropriate scarifiers etc. they can move to other rotations that do not include fallow. The final rotation will depend on the relative returns from livestock and cereals.

    *  Permanent rotation for small farmers.

    The Zaghouan 4 rotation offers many advantages for small farmers without tractors and farm machinery. They find cereal farming expensive and growing a single high yielding crop every four years (one quarter of their land) can provide a better return than growing a larger area of low yield cereal. They may not move from this rotation as their contractor may not have appropriate machinery.

    * A remedial rotation.

    The Zaghouan 4 rotation can also be used to stop the downward spiral of poor medic. The fallow followed by a cereal crop provides a good opportunity to clean out weeds and start again.