Pasture Management

& Plant

Identification

Country Noosa Nov 2015

Damien O’Sullivan

Grazing Solutions

Kingaroy

CO2 + H20 + Sunlight + Chlorophyll = CHO + O2

How many horses/cattle can I run on my property using the existing pasture?

A horse can eat 2.5% of its bodyweight in dry matter (DM)/day

450kg horse can eat 11.25 kgs/head/day

365 x 11.25 = 4100kgsDM/hd/year.

Area of land

Soil type

Pasture present

Land types

Blue gums on alluvial flats stocking rate is 1 Adult horse to 3ha. 6 ha/14.5 acres of this land could grow 4000kgs/ha

x 6 ha = 24,000kgs of grass. Only ⅓ of this is usable which gives 8000kgs DM/ha

of pasture If we have 2 horses @450kgs need 8200kgs

grass/yr, therefore there is almost enough DM for 2 horses for one year.

The other ⅔’s of grass is trampled or is consumed by soil & local fauna.

Land types

Iron barks & spotted gum ridges – Stocking rate 1AE to 6ha. This land type could produce less than 2000kgs of

DM/yr, 6ha = 12000kgs DM/yr. ⅓ of this is available = 4000kgs DM/yr. 2 horses @450kgs require 8200kgs grass for 2 horses therefore a shortfall of 4200kgs of feed/yr.

Soil type is the major determinant of carrying capacity

Carrying capacityAE = adult equivalent 450kgs

Blue gum on alluvial flats – Native 1 AE to 3ha

- Sown 1AE to 1 ha

Rainforest on basalts - Native 1 AE to 3-4 ha

- Sown 1AE to 2 ha

Tall open forests on basalts - Native 1 AE to 3 ha

- Sown 1AE to 2 ha

Tall open forests on steep hills & mountains - Uncleared 1 to 10 ha

- Native 1 AE to 5 - 6 ha

- Sown 1AE to 4 ha

Brigalow Softwood scrub Native - Native 1 AE to 3 ha

- Sown 1AE to 2 ha

Ironbarks & spotted gum ridges - Native 1 AE to 10 ha

- Sown 1AE to 6-7 ha

Mixed open forests on duplexes and loams uncleared 1AE to 8 ha

cleared native 1AE to 5-6ha

Carrying capacity of your property will vary due to: difference in soil types across the property current soil health rainfall and seasonal conditions type of pasture – native grass vs kikuyu health of pasture – horse sick pastures % weeds undesirable grasses – African lovegrass, giant rats tail grazing history of property - set stocking - overstocked - flogged! fertiliser history manure management history

Owners need to be realistic about the carrying

capacity of a property

The Pasture Mix Grasses: low growing vegetative plants that can tolerate grazing.

Forbs: non-woody broad leafed plants, common in winter rainfall years

e.g. flatweed, pigweed, bindweed etc.

Legumes: plants with a varying ability to fix nitrogen with the help of

bacteria in root nodules, important component of diet in grazing animals

eg: clover, stylos and lucerne.

Sedges: Grass like plants, e.g. nutgrass.

Woody weeds: plants with the ability to compete with pasture plants for

sunlight, nutrients and moisture.

Other Weeds: Any undesirable plant in a pasture that affects carrying

capacity of the pasture due to its un-palatability, competition with more

favourable species or presence of poisonous principles, eg; Blue

Heliotrope, Lippia, Catsear etc.

The Grass Plant

Grasses - 2 specific types

C3 grasses - use an enzyme called rubisco to fix carbon from the air during photosynthesis and the first stable product from the process has 3 carbon atoms hence the C3 classification. Weeping rice grass, wheatgrass, prairie – mainly temperate climates

C4 grasses use another enzyme to fix carbon from the

atmosphere during photosynthesis and the first stable product from this has 4 carbon atoms hence the C4 classification – mainly tropical climates.

C3 grasses C4 grasses

Moisture requirements Higher Lower

Sunlight requirements Lower Higher

Temperature range0º - 25ºC \

Optimum 25ºC15º - 45ºC \ Optimum 35ºC

Nutrient requirements Higher Lower

Grass quantity Lower Higher

Grass quality Higher Lower

Carbohydrate Fructan Starch

Non-structural carbohydrates (NSC) in grasses NSC in grasses are an important factor in

determining what is a suitable grass for horses.

Grasses that are suitable for ruminants such as cattle, sheep and goats are often not the most appropriate for horses.

Grasses with high levels of NSC can lead to laminitus in horses

GrassCarbohydate

Fructan Starch

Black Spear grass - Heteropogon contortus - C4

Kangaroo grass - Themeda triandra - C4

Pitted bluegrass - Bothriochloa decipiens - C4

Poa - C3

Stipa – C4

Wallaby grass – Danthonia - C4

Weeping rice grass - Microlena - C3

Wire grass - Aristida - C3

Native grasses

Grass & LegumeCarbohydate

Fructan Starch

Couch - Cynodon dactylon - C4

Clover – Medicago - C3

Creeping blue grass – Bothrichloa pertusa - C4

Green/Gatton Panic - C4

Kikuyu – Pennisetum - C4

Lucerne - Medicago - C3 Pectin

Medic - Medicago sps - C3

Oats (Avena sativa ) Barley (Hordeum vulgare)- C3

Pangola grass - Digitaria - C4

Paspalum - Paspalum dilitatum - C4

Prairie grass - Bromus sps - C3

Rhodes grass - Chloris gayana - C4

Ryegrass - C3

Setaria - Setaria sphacelata - C4

Tropical grasses & bighead

Oxalate in tropical grasses binds with calcium in the gut and is not digested by the horse

Buffel grass, setaria generally the most common causes in Queensland

Australian Equine Veterinarian Vol. 29, No.1, 2010

Getting the most from your paddocks

0

5

10

15

20

0 10 20 30 40 50 60 70 80

Cover of organic matter %

Annual s

oil

loss (

t/H

a)

Ground cover• Ground cover is any organic matter that stops

the impact of a raindrop on bare soil surface.

• Organic matter is grass, leaves, sticks and manure.

• Aim to have at least 90%+ ground cover at all times.

PerennialPasture

Annuals

Bare Ground

0

2000

4000

6000

8000

10000

Soil loss (kg/ha)

Soil loss depending on pasture type

When the level of ground cover falls below 90% you loose: Soil moisture Soil fertility

nutrients minerals carbon

soil biology bacteria fungi soil insects worms dung beetles

pasture productivity

Ground Cover is about Soil Carbon increase of 1% of carbon in top 30cm soil = an extra 144,000 litres of

water/ha

1 ha of land - 2% soil carbon = 84 tonnes of carbon

1 ha of land - 3% soil carbon = 126 tonnes of carbon

Soil - 3 times more carbon stored than the carbon in the atmosphere

Soil - 4 times more carbon stored in soil than in vegetation

A 0.5% increase in soil carbon on 2% of agricultural land would

sequester 685 million tonnes of CO2. Equal to Australia’s total yearly

CO2 emissions!!!

Recognising a good pasture is important as: Health & productivity of a pasture is indicated by the species present

Good pasture bulk is not necessarily productive pasture

Pasture budgeting, set appropriate number of horses – how much is edible

Know when to use fire, sown pastures, fertiliser

Pasture spelling to manage – weeds, unpalatable grasses

Identify changes in productivity over time

Early warning for invasive weeds

Confinement of any grazing animal on small areas will cause problems for

the animal, owner and the environment.

Plan your grazing Estimate how much pasture your property can grow and then

how many animals will be grazed on the area. Designate a sacrifice area if you have to totally hand feed due

to numbers or dry conditions Plan to have as many paddocks as possible but use electric

fencing. Permanent single wire or high visibility tape. Reels and tread in posts are very good.

Rest periods between rotations should be as long as possible. Pastures need rest - a spelling period over the growing season

is the easiest way to rejuvenate pastures.

Rotational grazing of pastures is the easiest way to rest pasture

Multiple paddocks, extra water

One paddock, one water, movable electric fences

Pasture Spelling

Paddock Management

Manure management is important and rotationally grazing horses reduces rough areas where manure accumulates.

When resting a paddock harrowing the paddock is useful to spread the manure.

If drenching horses leave them in a confined area so that the anthelminthic does not interfere with dung beetles in the grazing area.

Slashing can be useful to reduce weeds and bulk of old pasture, however tall mature grass can protect from loss of soil moisture, reduce wind and soil erosion and provide extra fodder.

Slash only if absolutely necessary for fire, weed control or to remove old unpalatable pasture.

Composting manure Maintains the fertility of your pasture - Two types

Anaerobic – long term 6months + Aerobic – short term 2 months needs aeration

Moisture levels in compost critical – Rain Add water Carbon:Nitrogen ratio Carbon – dry matter Nitrogen - green grass manure Ideal ratio is 25:1 Horse manure is 30:1 Need a cubic metre to be successful

Dung beetlesNatures recyclers

Bury dung Increase soil fertility Increase water infiltration Increase grass growth Reduce nutrient loss Reduce fly and parasite numbers Drench horses in winter to reduce losses or collect

manure after drenching Moxidectin based wormers friendly to beetles

Paddock Management

Pastures may need work if they have been grazed heavily for a long period of time. This may necessitate ripping the soil and planting new pasture.

Fertiliser may be necessary and a soil test will help determine if any nutrients or minerals are necessary. Most light soils will be low in phosphorus and nitrogen.

New pasture will need to be rested and allowed to go to seed before first grazing.

In selecting a pasture mix for Southern Queensland aim for the tropical species which make best use of the summer growing season. They are mainly C4 and lower in NSC.

A legume in the mix will help maintain soil nitrogen levels and provide extra nitrogen for the grasses.

Grass species to use in a pasture mix are:

Rhodes grass – varieties are Callide, Katambora & Finecut

Green panic or Gatton panic Creeping bluegrass - Bissett or Hatch Pangola grass - plant with runners only* Paspalum – likes heavier moist soils Kikuyu – plant with runners or seed, need good

fertile soils in a mixture with other pastures.*

* these grasses are in the hazardous range for oxalate and should only be part of a mix of grasses

Suitable legumes are

Lucerne Wynn cassia Lotononis Fine stem stylo Medic Clover

Be careful in wet winters as the clovers and medics can dominate and could cause problems with laminitis in horses or bloat in cattle/sheep if they are a high proportion of the diet.

When to plant a pasture

Before 50mms steady soaking rain Adequate soil moisture Have ground prepared early October to March for tropical pastures• Avoid mid-summer heat• Cooler times for temperate legumes• Early frosts• El Nino years have poor

establishment• Can be luck of the draw

Plants that can cause problems in Horses Stringhalt

Catsear, False dandelion, Flatweed - Hypochoeris radicata Dandelion Taraxacum officinale

Facial DermatitusPaspalum Paspalum sps dermatitis

BigheadBuffel grass, kikuyu, setaria

Staggers Ryegrass

LaminitisGrasses - C3 eg RyegrassDandelion - Taraxacum officinaleStorksbill - Erodium SpsWild oats - Avena sativaPlantain Sago weed - Plantago lanceolataSowthistle – Sonchus oleracea

Weeds

Many weeds can be a problem in small grazing

paddocks Weeds are often a sign of bare areas, drought,

overgrazing or lack of ground cover. Some environmental weeds need to be controlled

such as parthenium, lantana, giant rats tail and lippia.

Other weeds may just be part of the biodiversity in pasture and can be of benefit to horses.

Weeds of Southern Queensland is a very useful publication.

References & more information

www.equiculture.com.au/ www.goldcoasthorse.com.au www.safergrass.org/ www.kohnkesown.com/ www.rirdc.gov.au/publications www.wsq.org.au/ Weed Society of Qld www.horsesa.asn.au Horse SA