PHOTO GUIDE

TO GRAZING GREEN MEDIC

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 How to use the photo guide

    The photo guide should be used in combination with the sample disc below that is normally used to measure dry medic pods.



The sample disc shown above is made from cardboard. A hole 11 cm in diameter is cut in it.
It is used to sample green medic, to count dry medic pods and to measure the seeding rate for pods.

    The disc is thrown at random on the pasture and the following photos are matched to the pasture shown inside the hole.

    It is easier to make these samples rather than trying to match the pasture as a whole. Most pastures are not uniform and trying to estimate how much is "good, "average" or "poor" is difficult. The use of the sample disc allows one to be much more specific. Again if we use ten samples and perhaps 8 are average and 1 good and 1 poor. The pasture can be classed as average. 

Pasture composition

    As well as scoring the pasture in terms of density it is useful to assess the composition of the pasture.

This can be done with a pen.

Walk at random across the pasture.

Throw down the pen at least 50 times.

Each time the pen lands on the pasture mark down the composition under the point.

Example:
 

Object found under the point of the pen thrown at random on the pasture.

SCORE
(each time found under point)
TOTAL SCORE
  % GREEN MATERIAL

Pasture legume - medic, sub clover, etc.

1111   1111   1111  1111  1111  1111   1111
 28

53

Grasses or self sown cereals.

1111  1111 1111 
12

23

Broadleaf weeds

1111 1111   1111
12

23

Dry residues from previous year

1111 
4

Bare ground

1111 
4

Turning pasture production and pasture composition into grazing days.
 

    A grazing day is the amount of feed required per day by a breeding sheep.

A more detail description is provided below. It can be seen that the STANDARD UNIT is the 50 kg sheep at the later stage of pregnancy. Other stages, heavier sheep and lambs are compared to this unit.

Breeding sheep.
 

Live weight of sheep in kg.

Sheep not pregnant or early stage of pregnancy.

Sheep later stage of pregnancy.

Sheep lactating and with young lambs beginning to graze.

50 kg

0.7 grazing day

 1  grazing day

2 grazing day

60 kg

0.8  grazing day

1.1 grazing day

2.3 grazing day

Growing lambs
 

Live weight of lamb in kg.

Growth of 50 gm. per lamb per day

Growth of 100 gm. per lamb per day

Growth of 150 gm. per lamb per day

20 kg

0.5 grazing day

0.6  grazing day

0.7 grazing day

40 kg

0.7 grazing day

0.85 grazing day

1 grazing day

 

    The photo guide gives the Dry Matter production of the sample pastures.

    To convert Dry Matter (DM) into Grazing Days depend on a number of assumptions.

    + We have to assume some wastage of the pasture during grazing.

    + We have to assume a level of digestibility.

The digestibility will vary with the maturity of the pasture and the composition.

An estimate to work with is 2.5 to 3 kg of Dry Matter per day = One Grazing Day.

If the legume content is high (70% or more) the DM needed will be lower (that is 2.5 kg) and if the legume content is lower (30% or less) the DM needed will be higher (that is more of the pasture is grass and broad leaf weeds)

    The Grazing Days provided below are an indication only.

Photo 1.

Legume pasture in early autumn soon after first good rain.

Height of pasture 0.5 cm.

Bare ground and dry residues 95%

POOR ESTABLISHMENT OR REGENERATION

Legume content 5%

Production = 1 qx (100 kg) dry matter per ha.

Grazing days per ha. = 40   - that is 10 sheep on 1 ha for 4 days but at these low levels it is doubtful whether sheep could in fact recover this amount of DM.

Management - leave pasture to grow so there will be a complete cover of the ground.


    Reasons for poor germination

    * Poor rainfall caused early germination. This was not followed by good rain. First germination died and this is second germination.

    * Rainfall inadequate at time of seed production in previous spring and little seed produced.

    * Grazing management poor over previous years. Poor seed production and/or too many pods eaten during summer.

Photo 2.

Pasture Legume - Early autumn soon after first good rain.

  Height of pasture 0.5 cm.

Bare ground and dry residues 50%

AVERAGE   ESTABLISHMENT OR REGENERATION

Legume content 50%

Production = 4 qx (400 kg) dry matter per ha

Grazing days per ha. = 160

Management - leave pasture to grow so there will be a complete cover of the ground

  Reasons for poor germination

    * Poor rainfall caused early germination. This was not followed by good rain. First germination died and this is second germination.

    * Rainfall inadequate at time of seed production and little seed produced.

    * Grazing management poor over previous years. Poor seed production and/or too many pods eaten during summer.

Photo 3.

Legume pasture - Early autumn soon after first good rain.

Height of pasture 0.5 cm.

Bare ground and dry residues 10%

GOOD  ESTABLISHMENT OR REGENERATION

Legume content 90%

Production = 11 qx (1100 kg) dry matter per ha.

Grazing days per ha. = 440

  Management - leave pasture to grow so there will be a complete cover of the ground.

Reasons for good germination and high density

There was ample seed in the ground from previous medic pastures or from pods sown over a cereal crop.

Germination conditions have been good.



The next three photos take the medic pasture on to mid or late autumn. It is not possible to be exact as germination and growth depend on the rainfall. Under normal rainfall conditions this would be ten days later.


Photo 4.

Pasture Legume - Mid to late autumn

Height of pasture 1 cm.

Bare ground and dry residues 70%

POOR  ESTABLISHMENT OR REGENERATION

Legume content 30%

Production = 5 qx (500 kg) dry matter per ha.

  Grazing days per ha. = 200

Management - leave pasture to grow so there will be a complete cover of the ground.

   

 Photo 5

Pasture Legume - Mid to late autumn

Height of pasture 2 cm.

Bare ground and dry residues 35%

AVERAGE ESTABLISHMENT OR REGENERATION

Legume content 65%

Production = 11 qx (1100 kg) dry matter per ha.

Grazing days per ha. = 440

Management - leave pasture to grow so there will be a complete cover of the ground.

Photo 6.

Pasture Legume - Mid to late autumn.

Height of pasture  3 cm.

Bare ground and dry residues 10%

GOOD   ESTABLISHMENT OR REGENERATION

Legume content 90%

Production = 20 qx (2000 kg) dry matter per ha.

Grazing days per ha. = 800

Management - leave pasture to grow. Ground cover is almost complete but still a little early to graze. 


The next three photos take the poor, average and good legume pastures on to the next stage. It is now winter and the medic pasture has continued to grow provided there is adequate rainfall.

Photo 7.

Pasture Legume -Winter

Height of pasture 2.5 cm.

    Bare ground and dry residues 30%

POOR   ESTABLISHMENT OR REGENERATION

Legume content 70%

  Production = 20 qx (2000 kg) dry matter per ha.

   Grazing days per ha. = 800

This pasture would supply 24 kg of N to the following cereal crop.

Management - leave pasture to grow so there will be a complete cover of the ground. The pasture is gradually covering the ground but the low initial germination means it is slow to produce.

Photo 8.

Pasture Legume -   Winter

Height of pasture 3 cm.

Bare ground and dry residues 20%

AVERAGE  ESTABLISHMENT OR REGENERATION

  Legume content 80%

Production = 23 qx (2300 kg) dry matter per ha.

  Grazing days per ha. = 920

   This pasture will supply 28 kg of N to the following cereal crop.

Management - leave pasture to grow so there will be a complete cover of the ground.

Photo 9.

Legume pasture - Winter

Height of pasture  5 cm.

Bare ground and dry residues 0%

GOOD     ESTABLISHMENT OR REGENERATION

Legume content 100%

  Production = 38 qx (3800 kg) dry matter per ha.

  Grazing days per ha. = 1520

This pasture would supply 46 kg of N to the following cereal crop.

Management -  Ground cover is now complete. Heavy grazing will however reduce height and expose bare ground but light grazing could begin. It would be better to leave until 7- 8 cm. in height but if hay and grain supplies are running short grazing could begin. 


The next couple of photos show the pasture in spring. By spring the poor, average and good pastures have all grown to the stage that they have a complete cover of the ground. Of course the good pasture reached this stage earlier. Grazing started earlier and production was higher.

Photo 10.

  Pasture Legume - Spring.

Height of pasture  13 cm.

Bare ground and dry residues 0%

GOOD, AVERAGE  AND  POOR  ESTABLISHMENT OR REGENERATION

Legume content 100%

Production = 40 qx (4000 kg) dry matter per ha.

Grazing days per ha. = 1600

This pasture would supply 48 kg of N to the following cereal crop.
 

Management -  Ground cover is complete. Grazing at about 7 cm. is the optimum. This pasture is becoming under-grazed. With the 100% legume content it is not a serious problem but if there were weeds and grasses these would have grown tall and would begin to shade the medic.

    Example of pasture utilisation:

    If a farmer has a flock of 10 sheep to graze on this hectare of medic pasture it could be used as follows:

    Grazing (begun earlier) with 10 pregnant ewes for 30 days @ 1 grazing day per sheep                  = 300 grazing days.

    Grazing with 10 lactating ewes with lambs sucking for 40 days @ 2 grazing days per sheep & lamb = 800 grazing days

    Total                                                                                                                                    = 1100 grazing days

    This leaves 1600 - 1100 = 500 grazing days surplus which is necessary at this stage as the farmer does nor want to graze the pasture below the optimum 7 cm while it is green.

    The pasture continues to grow and support the sheep and their lambs. After the pasture has flowered, produced pods and these have dropped on the ground the surplus can be used up until the remaining pod supply is at the optimum level for regeneration.

Photo 11.

Pasture Legume - Spring.

Height of pasture  15 cm.

Bare ground and dry residues 0%

GOOD, AVERAGE  AND  POOR   ESTABLISHMENT OR REGENERATION

Legume content 100%

Production = 58 qx (5800 kg) dry matter per ha.

Grazing days per ha = 2320

This pasture would supply 70 kg of N to the following cereal crop.

Management -  Ground cover is complete. Grazing at about 7 cm. is the optimum. This pasture has become under-grazed. With the 100% legume content it is not a serious problem but if there were weeds and grasses these would have grown tall and would begin to shade the medic.