Chapter 7.2 Graze to keep desirable species productive and dominant

Introduction

Understanding how the desirable species grow helps you plan a grazing system that will encourage these species to become more dominant. Likewise, knowing the weak spots in a weed’s lifecycle helps you plan grazing tactics to decrease their level in a problem paddock. To aid in persistence, knowing when desirable plants are most vulnerable is key to protecting them. Annual plants are most vulnerable during establishment and flowering (seed set is critical for survival) and perennial plants are most susceptible following dry periods and during reproduction (where they set up for summer survival). For more information about matching plant growth and grazing management, see tool 7.5. For pasture assessment tips, see tool 7.6.

Establishing an effective process of grazing management is about tailoring the principles outlined in this procedure to meet your personal and business goals. There is no ‘right’ grazing management and considerable flexibility is needed to continually re-balance the needs of soil, pasture and animals.

There are three critical actions in this chapter:

• Assess your pastures to determine if your current grazing system is limiting the growth and persistence of desirable species. A number of pasture assessment techniques are described in tool 7.6. For mixed pastures (annual or perennial) based on introduced species, a good composition is: 60% desirable grasses, 30–40% clover and 0–10% weeds. In native grass-based pastures, the optimum clover content is 20% or less.
• Clarify the particular requirements of the species you have in your pasture, especially those that you want to increase or decrease and apply the appropriate grazing management as outlined in tool 7.5. Most pastures are quite a complex mixture of species and individual compromises for each paddock will be required.
• Measure, manage and monitor the impact of your actions on pasture composition. Monitor and record paddock management actions and changes in pasture composition using MLA Pasture Paramedic or MLA Pasture Health Kit (see signposts). Ensure your actions (for example, changed grazing pressure, fertiliser rates, tactical herbicide use, etc.), maintain or increase the proportion of desirable species in the pasture.

Shoots and roots

There is a general tendency among plants to maintain a relationship between root and shoot dry weight. When leaves and stems are removed by grazing, the plant compensates by lowering root growth and returning to a ratio characteristic for the plant. So, in short, continuously grazed grasses or ones maintained at one leaf stage will have small root systems like those on the left of the photo in figure 7.4, while pastures that are grazed and allowed to recover three live leaves look more like the plant on the right-hand side. Plants also have other feedback mechanisms in regulating shoot and root growth involving hormone control, such as the cessation of shoot growth, when roots are under drought stress, low soil temperature or poor aeration from waterlogging or compaction.

Pasture rest periods

All perennial species will be more productive and persistent under grazing that includes rest periods between periods of grazing. Rest periods are necessary to replenish root reserves that have been used to grow shoots and leaves during grazing (this is especially true for perennials such as lucerne) and complete reproductive phases. Growth rates of annual grasses such as annual ryegrass can also be improved by rest but their persistence in a pasture depends on seed-set in spring, rather than survival of individual plants over summer.

Deferred grazing

Deferred grazing is a tactic where livestock are excluded from pasture areas after the break of season to aid grass recovery and maximise germination and establishment of pasture seedlings. Sheep can be concentrated into containment areas, ‘sacrifice’ paddocks or laneways and supplementary fed. Containment areas and sacrifice paddocks should have low erosion risk and you will need to pay extra attention to animal health. The length of deferment should be governed by pasture growth but, to achieve the best outcomes for both the pasture and animal welfare, grazing is best deferred until pasture has achieved:

• Dry sheep – minimum of 500 kg DM/ha
• Ewes in late pregnancy – minimum of 1,000 kg DM/ha for single bearing ewes or 1,200 kg DM/ha for multiple bearing ewes.
• Ewes at the point of lambing or in lactation – minimum of 1,200 kg DM/ha for single bearing ewes or 1,500 kg DM/ha for multiple bearing ewes.

Pasture residues after grazing

The more green material (pasture residue) you leave after grazing the faster the regrowth, as photosynthesis is more quickly restored. During the growing season it is ideal to leave about 1,000 kg DM/ha (green material), but this is also dependent on animal class species and leaf number. If you cannot leave 1,000 kg/ha then place a higher priority on significant rest periods to encourage regrowth following grazing.

Seedling recruitment

Some pastures, such as perennial ryegrass, cocksfoot and prairie grass, recruit from seedlings and this is a tactic that can be used on pastures that have less than desirable plant numbers (figure 7.5). Steps include:

• Removing stock to allow the grasses to set seed in spring;
• Running a big mob of stock in a paddock over summer when the seed is ripe to ensure the seeds are knocked to the ground and dead pasture is eaten off to 1,000–1,500 kg DM/ha by the autumn break; and
• Resting pasture after the autumn break to let new seedlings establish.

Seedling recruitment tactics for phalaris and tall fescue have not proved successful based on poor seedling vigour.

Native grass seedling recruitment occurs using deferred grazing strategies to allow seed set and build up soil seed reserves provided pasture composition consists of at least 5-10% of native grasses.

SIGNPOSTS

WATCH

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More Sub Clover

Do you wish you had pastures filled with sub-clover but instead have pastures that are mainly grass dominant? The difference is often just a few simple management changes. This video steps though the stages of sub-clover growth and what management is required so we can consistently have good clover years.

Read

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Weed Control Hub

This section of the MLA website provides a variety of resources to assist you in reducing the weed population and residual seed banks in the soil through a planned control program prior to sowing, and ongoing attention to paddock composition with tactical use of grazing, fertiliser, and chemicals.

Persistent Pastures Hub

When it comes to persistent pastures, selecting the right pastures for your system, sowing in the right place at the right time and managing for the seasons is a strategy for success. There are many considerations when it comes to new and improved pastures – environment, varieties, composition, inputs, soils, establishment, and grazing management. Work through these considerations with resources and tools provided on the MLA Persistent Pastures Hub.

Sheep farming for meat and wool

Covers all aspects of sheep farming for meat and wool production throughout temperate Australia, and chapter 2 is titled ‘Pasture growth and management’.

How do I optimise seedling recruitment to avoid resowing?

Seeding is part of the natural life cycle of perennial grasses but allowing plants to mature and drop seed is not essential for their survival. However, encouraging optimal seeding is a strategy for some perennial grasses which tend to thin out due to hot and dry summers. There are a number of ways producers can encourage and manage seedling recruitment in their pastures.

Making perennial ryegrass-based pastures productive and persistent

Perennial ryegrass is a highly nutritious and palatable pasture plant, well suited to livestock production. Management strategies can maximise its productivity and persistence and maintain plant density without the need to resow regularly.

Making phalaris-based pastures productive and persistent

Phalaris is one of Australia’s best temperate pasture species. It can produce a huge quantity of highly nutritious feed when managed correctly. It is also a perennial that survives some very harsh conditions.

Maximising production from kikuyu-based pastures

Kikuyu is a subtropical perennial grass that can be highly productive, particularly during summer and early autumn when annual pastures have hayed off. Kikuyu pastures must be grazed hard to promote leaf growth to maintain feed value and need a strong legume component to provide winter production and supply nitrogen.

Intensive rotational grazing

Intensive rotational grazing systems involve livestock being moved frequently through a large number of paddocks, based on either a fixed time rotation or pasture growth.

Get the best out of set stocking

Set stocked paddocks are grazed for an extended period (a few months to a full year). Properly managed, set stocking is not a ‘set and forget’ system – it is a planned and monitored method of animal production. Set stocking a paddock even for a limited period provides the only reliable guide to determining paddock and animal performance.

How do I maximise sub clover establishment in existing pastures?

Sub clover is an annual plant that needs to germinate from seed and establish at the break each year. The germination and survival of those seeds and seedlings are closely related to grazing management over summer and after germination. Outlined here are grazing strategies that impact burr survival, seed softening and germination to help make every year a good sub clover year.

How do I manage grazing to maximise sub-clover seed set?

A pasture with a 40% sub-clover content relies on having at least 200kg/ha of sub-clover seed in the soil. While only 10–20% of this seed needs to germinate each year to achieve optimal sub clover density, repeat years of inadequate seed set will rapidly deplete the seed bank and subsequent pasture production.

How do I optimise sub clover-based pastures?

Sub clover is an essential component of the southern Australian feedbase, but its productivity is not being maximised for optimum livestock production. Good establishment and management of the sub clover life cycle will result in highly productive and persistent pastures which provide free nitrogen to the soil, greatly benefiting productive perennial grasses which also lift livestock production.

How do I manage soil health to grow high quality sub clover?

Does your sub clover have a leaf area smaller than a five cent piece and is the plant bright green with no mottling on the leaves? Is the sub-clover content of your pasture less than 10% in late winter and early spring? If you answered yes to any of these questions you may have an underlying soil constraint affecting sub clover production.

How do I replace outclassed or troublesome sub clover cultivars?

Outclassed or troublesome sub clover cultivars result in significant pasture and/or animal underperformance. The most common losses occur because the sub-clover contains oestrogen, resulting in ewe fertility issues, or are susceptible to plant diseases, resulting in lower annual production. Improvements in growth characteristics, pest and disease resistance also contribute to the widening gap between older and newer cultivars.

How do I determine why my sub clover is underperforming?

A productive pasture will have around 40% sub-clover content in spring. A sub-clover content consistently less than this over several years would suggest something is limiting growth. There are many possible reasons for poor sub clover growth, so it is important to make the correct diagnosis. This guide is designed to help identify what might be limiting sub clover growth – both common and less common reasons. Diagnosis involves visual observations, some testing and possible field confirmation.

How do I identify sub clover cultivars?

Identifying cultivars can be useful to determine if a pasture contains outclassed or oestrogenic cultivars and to assess how well newly sown varieties are competing against residual plants. There are at least 80 commercial varieties or cultivars of sub-clover in Australia, along with many naturalised strains and crosses. Accurate identification can be difficult and at times can only be made by experienced agronomists or researchers.

Deferred grazing for native grass recruitment

Deferred grazing strategies address several key measures of pasture performance that contribute to the successful rejuvenation of native pastures.

Grazing cropped land

A summary of the latest information on grazing winter crops from the Grain and Graze program. Experimental results, farmer information and observations are combined to paint a picture around grazing crops in Southern Australia. The guide identifies common principles for grazing crops as well as providing local insights into different responses and management approaches required in different parts of the country.

Restoration of degraded grazing country in the semi-arid areas of NSW

Livestock favour more palatable species within a paddock which often results in less palatable species becoming dominant. In many areas set stocking combined with higher stock densities has contributed to vegetation change and land degradation. Contains groundcover targets for semi-arid areas of western NSW. 

Improve production from native pastures

Native perennial grasses can also increase stock performance. Many are summer active and provide quality green fodder in summer on low fertility, acidic soils. While a large proportion of the high rainfall zone of Australia is “native pasture”, farming practices have resulted in much of the area being invaded by annual grasses and weeds with only a small proportion of natives remaining in many paddocks.

EverGraze Exchange – The Nuts and Bolts of Grazing Management

This Exchange provides the principles, with evidence from research, for optimising pasture growth, utilisation, environmental management and livestock performance from pastures. Tools and processes are provided to guide planning and monitoring and apply the principles to achieve the best outcomes for the given farm system.

Grazing management systems explained

Profitable grazing systems that also improve the farm and wider environment. The steps to achieving this include the use of perennials, high performing livestock enterprises and best management practices with a whole-of-farm land class approach.

Growing and using chicory on the East Coast

Chicory is a summer-active, deep-rooted perennial herb that is suitable for areas too wet or too acid for lucerne and uses soil water at depth to help reduce soil salinity. Chicory provides herbage with high digestibility and high zinc, copper, manganese, magnesium, phosphorus, calcium and potassium levels, from October to April. It is usually more nutritious than grass pasture species.

Growing and using chicory in WA

Chicory is a summer-active, deep-rooted perennial herb that is suitable for areas too wet or too acid for lucerne and uses soil water at depth to help reduce soil salinity. Chicory provides herbage with high digestibility and high zinc, copper, manganese, magnesium, phosphorus, calcium and potassium levels, from October to April. It is usually more nutritious than grass pasture species.

Growing and using lucerne in southern Australia

Lucerne provides quality forage for livestock over spring, summer and autumn and uses soil water, helping to reduce soil salinity and acidity. Lucerne must be rotationally grazed with a 6-week spell between grazing, but managed correctly, can persist for more than 10 years. Lucerne suits well drained, alkaline to mildly acidic soils.

Kikuyu is king on the south coast of WA

Kikuyu can provide green feed for livestock in summer and autumn and help reduce soil salinity and wind erosion on the south coast of WA. Kikuyu is a summer-active, deep-rooted subtropical perennial grass suited to sandy soils which is highly profitable when properly managed with companion species.

Grazing phalaris for production and persistence

Strategic rotational grazing can greatly improve the persistence and productivity of phalaris pastures especially in challenging conditions. Low soil pH and high available aluminium in the topsoil and/or subsoil will reduce production and persistence of phalaris. Prostrate, semi winter dormant cultivars are less productive but more tolerant of set stocking. Winter active cultivars require rotational grazing for good survival and production.

Productive, persistent perennial ryegrass

Perennial ryegrass provides large quantities of high-quality, winter–spring feed. Cultivars are available with endophytes that improve persistence without affecting livestock production. Strategic grazing and seedling recruitment can improve perennial ryegrass persistence. Cultivars bred from northwest Spanish genetics show increased persistence and out-of-season growth compared with traditional cultivars.

Growing and using summer-active tall fescue

Tall fescue is available as both winter-active and summer-active cultivars and these suit different environments and soils. This fact sheet provides information on how to establish and manage summer-active tall fescue in higher rainfall regions of southern Australia. Tall fescue grows vigorously in spring and summer and needs intensive rotational grazing to avoid becoming rank and unpalatable. Tall fescue is a relatively weak seedling and requires careful management pre and post sowing to ensure success.

Identifying native pastures of eastern Namoi

Encouraging native perennial grasses in existing pastures will have the benefit of lower input grazing systems, persistent pastures that are commonly drought hardy, improved ground cover and soil stabilisation (structure), contributions of litter and organic matter which enhance soil micro-organisms, increased water use of available rainfall, reduced soil acidification rates, improved species diversity and conservation value and better weed competition.

Management of native pastures in Victoria

Learn to identify native grasses and invasive annual species and increase grazing pressure in early-mid spring to reduce competition from annual grasses and legumes. Remove stock in late spring–early summer to allow native grasses to seed, then graze in mid-late summer.

Improving subtropical grass pastures on the south coast of Western Australia

This bulletin reports the findings of a research project funded by DPIRD and MLA that investigated methods to improve legume content and increase production of both kikuyu and panic-based pastures on the south coast of WA.

How do I improve my subtropical grass-based pastures in WA?

Subtropical perennial grass-based pastures are productive and make a valuable contribution to forage production in southern WA but maintaining productivity and legume content can be challenging. They are useful for filling the feed gap in summer/autumn, resulting in increased stocking rates and reduced reliance on supplementary feeding.

NSW Department of Primary Industries & Regional Development Soils

Technical information on soils, fertilisers, soil biology and constraints, specific to NSW. 

NSW Department of Primary Industries & Regional Development Pastures and rangelands

Information on pasture species and varieties, mixes, establishment and management specific to NSW. 

Queensland Department of Agriculture and Fisheries Soil management

Technical information on soil properties, testing and conditions for Queensland.  

Queensland Department of Agriculture and Fisheries Grazing and pasture management

Technical information on pasture and land management for Queensland. 

Agriculture Victoria Land and pasture management

Technical information on pastures, including feed budgeting and grazing management in Victoria. 

Agriculture Victoria Soil

Technical information on soils, including managing problem soils and monitoring in Victoria. 

Agriculture Victoria Understanding soil tests for pastures

Technical information on soil test results, including key nutrients and soil types specific to Victoria. 

WA Department of Primary Industries and Regional Development Measuring and assessing soils

Technical information on soil physical, chemical and biological characteristics and managing these for productivity in WA.

WA Department of Primary Industries and Regional Development Managing soils

Technical information on soil productivity and managing soil constraints specific to WA. 

WA Department of Primary Industries and Regional Development Rangelands

Technical information on managing complex and extensive rangelands ecosystems in WA. 

WA Department of Primary Industries and Regional Development High rainfall pastures

Technical information on managing high rainfall pastures in WA. 

Tasmania Department of Natural Resources and Environment Land management and soils

Technical information on choosing and managing pastures and pasture and forage pests specific to Tasmania.

SA Department of Environment and Water Soil and land management

Technical information on soils, fertilisers, pasture species and growth rates specific to SA.

Use

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Pasture Health Kit

Managing ground cover to improve pasture sustainability and productivity can increase available rainfall for plant growth by up to 150 mm per year. This field kit for producers helps assess pasture health in the paddock.  

MLA Pasture Paramedic

A decision-making tool that allows rapid assessment of pasture condition in the medium to high rainfall zones of southern Australia, northern NSW and the WA wheatbelt.

Making Better Fertiliser Decisions for Grazed Pastures in Australia

Provides guidelines for improving fertiliser decisions for grazing operations across Australia and results from pasture-fertiliser experiments on nutrient loss.

ATTEND

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Grazing Fundamentals EDGE®

A one-day workshop that gives producers a broad understanding of the environment in which they operate and the core principles behind successfully maintaining grazing land condition and long-term productivity.

Grazing Land Management EDGE®

Designed for producers to develop a thorough understanding of the grazing land environment in which they operate to strategically manage their grazing business to optimise land condition and productivity in the long-term and begin developing grazing land management plans for their properties.

Pasture Principles

Producers follow the program for a 12-month pasture production cycle to learn a set of guiding principle to manage pastures confidently regardless of the season, situation or system.