Sustainability in Grazing Systems

This flashcard set covers the lecture on sustainability in grazing systems, focusing on definitions, indicators like ground cover and soil pH, land condition models, and historical research evolution.

What serves as the interface between the soil/plant and the animal in a grazing system?

The sward.

According to the transcript, what is the core goal of sustainability in a grazing system?

To remain viable and productive over the long-term without degrading resources like soil or the feed base.

What is the primary difference between a natural ecosystem and a managed grazing system in terms of stability?

Natural ecosystems are ecologically stable units in balance; imposing management (grazing, fertilizer, species changes) shifts that balance and changes the stability.

Why is soil pH decline often observed following the establishment of a grass-legume pasture?

It is caused by management changes, specifically legumes fixing nitrogen and receiving fertilizer.

What management decision is required to maintain soil pH when it declines due to intensive pasture management?

Applying lime.

How does the transcript define a broad outlook on sustainability in agriculture?

It enhances environmental quality and the resource base, provides human food and fiber, is economically viable, and enhances the quality of life for farmers and society.

What are the two key context-specific goals for sustainability in a grazing system?

1. Enhance the productivity and stability of production. 2. Enhance the stability and predictability of the grass-legume balance.

What are the characteristics of effective sustainability indicators?

They must be cost-effective, easy to use, easy to analyze, and able to show trends over time.

What is considered a baseline percentage for ground cover to maintain a sustainable grazing system?

Above $70\%$, with above $90\%$ being ideal to ensure runoff and soil losses are negligible.

In the 'rolling ball model' of land condition (Levels A, B, C, and D), what is the management implication of a ball rolling down the slope?

It represents degradation that is easy to cause through management but extremely hard, if not impossible, to reverse to get back up the slope.

What efficiency metric is used to compare production between locations with different annual rainfalls?

Kilos of beef produced per hectare per $100\,mm$ of rain.

How does nitrogen fixation from legumes act as a more sustainable option than nitrogen fertilizer?

Legume nitrogen is 'drip-fed' into the system based on appropriate plant growth conditions and the breakdown of biomass, rather than being added as a large single load.

According to the transcript, how much phosphorus should be applied back to the system per year based on stocking rate?

$1\,kg$ of phosphorus per hectare per year for each DSE.

What were the findings of the 2000 Scott et al. study regarding the most sustainable pasture type?

The grass-legume mix was the most sustainable, as it was a fertilizer-responsive pasture.

What was the name of the project conducted between 2000 and 2006 that used farmlets to study grazing management impacts?

The Cicero project.

According to the outcome of the Scott et al. (2013) paper, what management actions lead to the most profitable and sustainable outcomes?

Maintaining desirable perennial grasses and adequate legume content, enhancing soil fertility, and employing flexible rotational grazing.

What carbon footprint value did Brock Hett (2013) calculate for greasy wool at the farm gate using life cycle analysis?

$24.9\,kg$ of $CO_2$ produced per kilo of greasy wool.

What are the three categories of factors that dictate what species can be grown in a particular location?

Climate, landscape, and soil.

What are the six ways to run a sustainable grazing business as summarized in the final stages of the lecture?

1. Increase productivity/profitability. 2. Increase water use. 3. Protect on-farm assets. 4. Create biodiversity opportunities. 5. Reduce offsite impacts. 6. Improve producer satisfaction and capacity for change.