Agriculture (0600) | Extensive and intensive pasture management

Welcome to Pasture Power! Extensive and Intensive Grazing

Hello future agricultural experts! This chapter is all about how we manage the land that feeds our livestock—the pasture. Whether you are dealing with a small plot or vast open range, how you manage grazing directly affects the health of your animals and the health of your soil.
We will learn the difference between 'free-range' (extensive) and 'highly managed' (intensive) farming, and why farmers choose one method over the other. Don't worry if the terms sound complex; we will break them down into simple, practical ideas!

1. Understanding Pasture Vegetation (8.1a)

Pastures aren't just patches of green. They are carefully managed ecosystems containing different types of plants that serve specific nutritional purposes for grazing animals.

Types of Vegetation in Grazing Lands

The vegetation on grazing land is typically made up of three components:

• Grasses: These form the bulk of the grazing feed. They provide energy for the animals. Examples include Rhodes grass and Kikuyu grass.
• Legumes: These are incredibly important because they improve soil fertility. They have root nodules containing bacteria that perform nitrogen fixation, turning nitrogen from the air into useful nutrients in the soil. They provide high protein for the animals. Examples include Clovers and Lucerne (Alfalfa).
• Bush/Shrubs: These are woody plants whose leaves and young shoots are eaten by certain animals, a process called browsing. This is common for animals like goats, sheep, and camels.

2. The Core Difference: Extensive vs. Intensive Grazing (8.1c)

The biggest factor determining whether a pasture system is extensive or intensive is the amount of land used, the number of animals involved, and the level of management effort.

Extensive Grazing Systems

This method is used when land is cheap and plentiful, often in drier climates or remote areas.

• Definition: Using large areas of land with a low number of animals per hectare (low stocking rate) and minimal human intervention.
• Management Style: Usually unenclosed grazing systems (open range or common land). Livestock often roam freely or are loosely herded.
• Analogy: Imagine hiking across a vast national park. You see very few people (low density) and the environment naturally manages itself.

Intensive Grazing Systems

This method is used when land is expensive or when farmers want to achieve maximum production (e.g., high milk yield). It requires high investment in inputs like fences, water, and fertiliser.

• Definition: Using small areas of land with a high number of animals per hectare (high stocking rate) and constant human management.
• Management Style: Always enclosed grazing systems, usually divided into smaller sections called paddocks.
• Analogy: Imagine a small, highly productive vegetable garden that needs constant weeding, watering, and feeding (fertiliser) to keep producing.

3. Management Techniques for Optimal Pasture Use (8.1c, 8.1e)

A. Rotational Grazing (Intensive Improvement)

Rotational grazing is a key technique used in intensive systems to improve pasture utilisation. It involves dividing the total pasture area into several small, fenced areas called paddocks.

How it Works:

1. Animals graze one paddock intensely for a short period (maybe 3–7 days).
2. The animals are then moved to the next paddock.
3. The first paddock is left to rest and regrow completely before the animals return.

This resting period is crucial. It allows the grass roots to recover, store energy, and grow new leaves, leading to higher overall pasture yield and healthier plants. This system ensures the grass is utilised efficiently rather than being constantly grazed down to the ground.

B. Zero Grazing (The Highest Intensity)

The term zero grazing means the livestock are permanently housed or confined to a very small area (like a pen or feedlot).

• Process: The feed (grass, forage, hay) is harvested (cut) and carried to the animals. This is often called the Cut and Carry system.
• Benefit: Maximum control over feed intake, energy expenditure, and production. It is highly efficient for very small land holdings or when specific high-value animals (like pedigree dairy cows) need precise management.

4. Extensive Management and Carrying Capacity (8.1d)

In extensive systems, management focuses on protecting the natural environment and ensuring long-term sustainability.

Key Terms in Extensive Management

• Stocking Rate: The number of animals kept on a specific area of land (e.g., 1 cow per 5 hectares).
• Carrying Capacity: This is the maximum sustainable stocking rate. It is the highest number of livestock the pasture can support indefinitely without causing damage or degradation.

The Dangers of Overstocking (A Major Problem)

If the stocking rate exceeds the carrying capacity, the land is overstocked. This leads to serious problems:

1. Pasture Degradation: Plants are eaten down too far, preventing them from regrowing. Good, palatable grasses die out, allowing undesirable species (like weeds or tough bush) to take over.
2. Soil Erosion: Heavy grazing removes the protective grass cover, leaving bare soil vulnerable to wind and water erosion.
3. Soil Compaction: Too many hooves walking on bare soil compacts it, making it difficult for water to infiltrate and for grass roots to grow.
4. Poor Animal Health: Animals compete for limited, poor-quality feed, leading to low production and increased disease risk.

Avoiding overstocking is the single most important rule in extensive pasture management.

Bush Control and Fire (8.1d)

In open rangelands, bush encroachment (when woody shrubs take over grass areas) reduces the available feed for grazing animals. Farmers must control this:

• Bush Control: Methods include mechanical removal (cutting), chemical sprays (herbicides), or biological control (using goats that browse heavily on the bush).
• Use and Misuse of Fire: Fire is a common, cheap tool in extensive areas, but must be managed carefully.
  • Proper Use: Burning off thick, old, unpalatable grass (called "tussock") to encourage a flush of fresh, nutritious green growth beneath. It can also help control certain bush species and ticks.
  • Misuse: Uncontrolled fires burn all organic matter (humus) from the soil surface, destroy new grass seedlings, and leave the land bare and susceptible to erosion during the next rains.

5. Establishing and Improving Pastures (8.1b)

A farmer may choose to establish an improved pasture rather than rely on natural grazing land to increase the quantity and quality of feed available.

Step-by-Step: How Improved Pastures are Established

Establishing an improved pasture often involves cultivating the land and sowing specific, high-yielding grass and legume varieties.

1. Land Preparation: Clear existing vegetation (stumping, removing bush), plough and harrow the soil to create a fine seedbed.
2. Soil Improvement: Test the soil pH and nutrient levels. Apply lime if needed to adjust pH, and add appropriate inorganic or organic fertilisers (especially phosphorus, which helps root establishment).
3. Selecting Seed: Choose high-quality seed of grass and legume species suited to the local climate and soil (e.g., a mixture of a good grass like Star Grass and a nitrogen-fixing legume like Desmodium).
4. Sowing: Plant the seeds at the correct time (usually just before the rainy season) and at the correct density (seed rate). This can be done by broadcasting or using a seed drill.
5. Initial Management: Control weeds aggressively, and do not graze the pasture until the new plants are well established and strong enough to withstand being eaten (usually 3–6 months).
6. Fencing and Water: Install necessary fencing (to allow for rotational grazing) and ensure reliable water points are available in all paddocks.