Lecture 2: Native Pasture Classification and Distribution

what is the key driver of dairy business success across Aus?

-proportion of pasture in diet

which country (in developing world) have the highest average size of agri holdings?

(ruminant production)

-aus

how much feed energy do pastures contribute to ruminant production?

>90%

definition:

rotational grazing

-pasture management practice where livestock are moved regularly between different sections of pasture

general characteristics:

native pastures

-diverse with many grass spp but a few contain monocultures (single spp)

-some nutritious native legumes/herbs grow in native pastures but preferential and will disappear under grazing

-pastures in woodlands contain shrubs/trees that are sometimes browsed

-Most native pastures can contain plants that have toxic properties

How are plants classified botanically?

Family→Genus→Species→Variety

Black Speargrass pasture

-diverse

Mitchell grass pasture

-monoculture

what are the main source of tropical grass spp?

-Andropogoneae (total % of spp: 11.9)

-Paniceae (24.7%)

what are the temperate spp?

-Agrosteae (total % of spp: 8.2)

-Aveneae (6.3%)

-Festuceae (Poeae) (16.5%)

common name:

Festuceae

-fescue tribe

common name:

Paniceae

-millet tribe

Themeda triandra

Cenchrus cillarus

Erogrostis curvula

decreasers under grazing

-3P grasses

-native perennials, productive, palatable grasses

increasers under grazing (not preferred)

-native perennial grasses

-wire grass

increasers under grazing (less preferred)

-grader grasses

-annual grasses

classification:

native pastures

-appearance (tall or short)

-vegetation characteristics (grasslands, woodlands, shrublands)

-climate (humid to arid)

where are semi-arid dry savannah mainly found?

-S. Sumaliah

-N.E. Brazil

-C. Aus

summary:

Mitchell grass

-excellent native pasture (Astrebla spp)

-sheep country

summary:

Mulga country

-sparse pasture

-edible fodder used during drought feeding

summary:

Spinifex

-large areas

-low rainfall

-poor grazing

summary:

humid savanna (indonesia)

-short, dry season

>700 mm rainfall/yr

-woody plants originally present as tall trees or shrubs

-regular burning

humid savanna (indonesia)

summary:

humid savanna - PNG

-Markham Valley

-originally trees

-cleared and burnt

-pasture grazed by cattle

-high potential for degradation

summary:

humid savanna (PNG)

N. QLD, Brigalow Zone

(subhumid savanna)

summary:

subhumid savanna - SE QLD

-short, dry season

500-700 mm rainfall/yr

-woody plants are mostly tall trees and shrubs

-regular burning

-monsoon tallgrass woodland (Mt. Garnet)

-monsoon tall grass (N. Aus)

summary:

mulga - semi arid savanna

(Acacia Aneura)

-long, dry season

<500 mm rainfall/yr

-woody plants usually present as low shrubs

-irregular burning

Mulga (Acacia Aneura)

-semi arid savanna

Mulga (Charlesville)

-lightly grazed

summary:

Acacia aneura

MULGA

-inland Aus

-shrub or small tree

-yellow flowers

Mitchell grasslands

-semi arid savanna

spinifex (Triodia spp)

-arid savanna

Spinifex

Triodia spp

(Spinifex)

summary:

Triodia spp

C4: extreme heat & drought (soil stabilization)

-perennial hummock-forming grasses

-mainland Aus

-arid and semi arid

-NOT related to coastal Sinifex genus

-20% of Aus land area

-nutrient poor soils (sands, plains, rocky outcrops)

NZ

-temperate rye grass

NZ

-temperate rye grass clover pastures

What are the stocking rates for Mitchell grasslands?

• Cattle: 1b/12-16ha

• Sheep: 1b/2-3ha

What is the scope for improvement in native pastures?

• Better management and stocking rates ​

• Augmentation with exotic legumes, grass, and fertilizer

• Replacement with improved pastures and fertilizer