MEDIC PASTURE

Grazing medic pods during summer


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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.

YOU ARE HERE

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

 

Management objectives for medic in summer
 

The main source of feed in summer with the cereal-fallow rotation is the cereal stubble.

Farmers do not manage it. They simply let the livestock eat it.

For medic pasture grazing management is needed. Two conflicting objectives need to be balanced.

Livestock production from medic pods which are a quality source of feed.

Against

The need to reserve some pods containing seed for future regeneration of the medic pasture.

       Livestock production.

The dry medic straw and pods provide a valuable source of quality feed for livestock. The pods contain seed. The seed has a high protein content. The combination of seed and pod is a medium level protein feed and livestock will gain weight on medic pods. It is important to utilise the dry medic as it is a large part of the pasture output.

Sheep grazing dry medic in summer. Notice they have their heads down and are concentrating on the dry pods which have fallen on the ground.

Here are the medic pods. They are a good food source for sheep during summer. There are plenty of pods in this field to feed the sheep and leave a reserves for regeneration in future years.

     Medic regeneration - the pod reserve in the soil.

    Not all the medic pods can be eaten. Some must be left for the regeneration of the medic pasture in the following year (permanent medic pasture of Zaghouan 4 rotation) or the year after the cereal crop (classic medic - cereal rotation).

The objective is to leave an ample number of pods. This will provide seed for a dense pasture in the autumn. A dense pasture will cover the ground more quickly and produce more feed in autumn and winter. Ample supplies of seed are particularly important in the early stages of a medic pasture.

Over the years the pod reserves in the soil will build up. A single failure in pod supply, for example a spring drought, will not destroy the pasture as there are reserves of pods in the soil. While ample reserves should be left for regeneration they represent only a small part of the production of a good pasture. Less than 10% of the pods need to be left in most cases. It is an investment in future pasture production that has a high pay back.

Early Summer
 

    * Pods drop on ground.

    In early summer the green pods will ripen and drop on the ground.

A good medic pasture (for example the pasture at Le Kef, Tunisia, shown on the cover of our book Sustainable Dryland Farming, Cambridge University Press 1996) will produce a dense mat of pods about 2 to 3 cm thick. These will be under the dry medic straw. Livestock will graze continuously through from the green to the dry pods.

Sheep are the best form of livestock for grazing dry pods. They will pick up the pods better than cattle but cattle can harvest the pods particularly at this early stage when they are thick on the ground.

If pod holding medic has been used to establish the pasture the pods will not drop on the ground rapidly when dry. They will remain on the plant and will be easier to harvest both by the cereal harvester and by the grazing animal. Farmers need to take more care during this period to avoid over-grazing the pods.

    * Grazing management.

    If the medic pasture on the farm has been planned to be in balance with the livestock there is little danger of over-grazing during early summer.

The problem of over-grazing can arise if there is an inadequate area of medic in comparison to the farmer's flock.

Where more livestock are suddenly moved onto the medic the stocking rate increases dramatically and causes over-grazing. This may occur when weedy pasture on the farm is ploughed for the cultivated fallow. The sheep grazing the inadequate weeds on the fallow now have nothing to eat except a little grazing on roadsides and field boundaries.

The green maturing pods are over-grazed, they do not mature and drop on the ground.
Another major cause of over-grazing is sheep that move in from the rangeland. They move in to graze the cereal stubble in late spring or early summer but often the feed resources in the rangeland are exhausted before the cereal crops have been harvested and the stubbles are available for grazing. 

The sheep are desperate for feed while they wait and medic pasture is at its most productive at this stage in early summer. Farmers are tempted to sell their medic pastures to flockowners from the rangeland. This is particularly true if the farmer has an inadequate number of sheep in comparison to the medic. He will have a large amount of feed and will have made a large investment in pasture establishment but his own sheep are insufficient to eat all the available feed. His profit will be low in comparison to the investment.

In these circumstances he is tempted to sell the surplus. The result is usually a complete disaster.

It is almost impossible to control the grazing of the large influx of sheep on the pasture. Besides having paid for the pasture the flockowners have a right to eat it all. All the pods are eaten and the medic pasture fails to regenerate in future years.

The extension agent can exhort the farmer not to sell the grazing but the farmer has outlaid funds (even if better planning would have saved money) and wants a return. The solution is to delay the sale of the grazing until all the pods have dropped. It is more difficult for the sheep to pick up dry pods off the ground. It takes time. There is a greater opportunity for the farmer to intervene and try and save some pods for future regeneration (see below).

    * Fattening lambs.

    The best utilisation of the medic pods is to fatten the male lambs for a quick sale.

One of the weaknesses of the cereal-fallow rotation is that the quality as well as the quantity of green pasture and dry feed is poor. Sheep gain weight in early summer when the stubble contains grain and then lose weight. The total amount of feed required is considerable. For long periods lambs are eating a maintenance diet without gaining weight. When feed quality improves they gain weight again and return to where they were before. Medic provides good quality feed for uninterrupted growth. Less feed is required in total. Farmer are well aware of this but at present can only finish their lambs to a good weight by using expensive purchased or harvested grain.

Once the lambs have reached a satisfactory weight they should be sold. This reduces the feed requirements of the whole flock over summer.

    * Using the cereal stubble.

    Once the cereal crop has been harvested the stubble is grazed. This can provide some good grazing. Barley stubble is better than wheat stubble. The stubble contains some fallen grain and the chaff which have a higher feed value. Once these have been selectively eaten (again sheep are better than cattle) the feed value of the stubble drops away rapidly.

Most farmers will use the dry medic pods and the stubble together. This will lift the value of the stubble.

The effect will not be as great as in winter when high protein green medic was mixed with cereal straw. Pods are only medium level protein (medic seed is a high protein feed but the pod is not so the combination is an excellent medium protein feed) but mixing them with cereal stubble will prevent sheep losing weight.

Again it is important to graze on the dry medic and the stubble each day to maintain the nitrogen levels in the sheeps' rumens.
 

Late summer
 

    The dry medic pods will become exhausted during summer. Sheep have a great ability to pick up pods off the ground and even dig them out of the surface of the soil. They will eat almost all the pods if allowed to do so.

    * Measuring the pods.

    As the supply of pods is eaten during the summer it is important to start measuring the amount remaining on the ground.

This is easily done ( Measuring the pods ) using a simple sampling disc.

    The pods from the sample are opened and the seeds are counted. This may seem tedious but different cultivars of medic have different numbers of seeds in each pod. If the spring is dry there will be fewer seeds in each pod. From the seed count we can estimate the reserve of seeds in the soil.

    This should be done every week towards the end of summer.

   * Level of reserves.

    We have recommended that grazing stops when the level of seeds on the surface is about 2000 medic seeds per square m.

This figure is based on the assumption that there will be some further loss of seed due to:-

    + the harvesting of pods by ants during the remainder of the summer.

    + In the autumn some of the seeds will germinate with the first autumn rain. The land will be cultivated for cereals (traditional Australian medic - cereal rotation) and these seedlings will be killed.

    + Shallow cultivation will be used for the cereal crop which keeps the pods near the surface of the soil. Even with shallow cultivation some pods will be lost by burying too deep.

    In the following season (after the cereal) the medic will regenerate from the reserves carried over. The percentage hard seed varies considerably with different species, varieties and cultivars or ecotypes. Perhaps 50% of the seed left in the reserve will "soften" and germinate. The remainder will stay in the ground and germinate in future seasons.

    Hopefully, the pasture that germinates 18 months later will have a density of between 250 and 500 seedlings per square m. This will provide an excellent dense pasture that will cover the the ground rapidly.

    * Second year medic.

    While the losses of medic seed through the cereal phase may be high farmers should reduce reserves below 2000 medic seeds per square metre even if they are leaving the medic for a second year (see Decision time in autumn). 

We recommend that farmers in the WANA region do not launch straight into the traditional Australian rotation of cereal-medic. Instead they leave the medic pasture for a second season to provide grazing and for them to acquire more experience in grazing management.

With the Zaghouan 4 rotation the medic pasture is left for regeneration in the second and third years.

    The amount of seed that "softens" and germinates in the first autumn season can be very low for some medics. With some ecotypes only 5% will germinate but if we say that a mixture of different medics has a 15 to 20% germination rate in the first autumn we will still need 2000 seeds to provide a pasture of between 250 and 500 seedlings.

    * Judging by eye.

    The measuring of the pods and the counting of the seeds may seem a tedious operation but it is worthwhile in the early years of the medic rotation.

After a number of years farmers will judge the reserves without weekly measurement.

It is still important to open the pods. A dry spring can provide a nasty shock. There may be plenty of pods but they may have no seeds or only one.

    * Amount eaten.

    If you started with a dense mat of medic pods in late spring or early summer nearly all of them will have been eaten by the sheep.

A reserves level of 2000 medic seeds per square m. will in most cases represent something like 500 pods per square m. which would be less than 10% of the original production.

Drought

        Drought can be total and the medic pasture may not germinate but the more common drought is a dry spring.

The production of pods and the number of seeds in each pod is reduced. For a first year pasture this reduced number can still be enough to enable regeneration in future years but only if tight control is kept on the grazing management from early rather than late summer.

Rather than allowing the sheep to eat 90% of the pods produced it may be none.

For older medic pasture the effect of zero or low production in a single year is not so important.

For a permanent medic pasture there is little effect. These areas can be sacrificed by over-grazing to protect first year medic pastures.