Fact Sheet: Do you need to renovate your Perennial Pasture

Do you need to renovate your Perennial Pasture

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Late winter and spring is an ideal time to have a good look at your perennial pastures. Assessment of pasture quality will allow you to decide if you will be able to restore them using management techniques such as application of fertiliser or grazing management, or if they need oversowing or complete renovation.

This is a good time of year to do it because

  • You want to assess the proportion of desirable species whilst all plants are still actively growing
  • If you plan to renovate, thius is a good time to put strategies to manage weeds in place
  • It is a good time to check your sward for RLEM (red legged earth mites) and use TimeRite (https://www.wool.com/land/timerite/) to reduce the oversummering egg population

Perennial pasture quality can be classified by the percentage of improved grasses and clover in the pasture.  One way to assess this is to make a square approx. 50cm x 50cm and randomly place this in the paddock in at least 10 separate areas.  Estimate the proportion of the square that is covered by each species (See Table 1). It is easier to look at the percentage of the square occupied by species type rather than counting plants as perennial pastures will tiller, making plant boundaries difficult to determine. Accurate identification of pasture species is important in this process, as is the identification of the weeds present.

Table 1: Percentage of improved grasses and clover in a pasture (%) *

Species Excellent Good Average Poor
Improved grass (perennial ryegrass, phalaris, cocksfoot etc) > 50% 30% to 50% 10% to 30% <10%
Clover and medic (sub clover, balansa clover, white clover, lucerne) > 40% 20% to 40% 5% to 20% <5%

MLA have recently made assessment of degraded perennial pastures easy by producing a tool called Pasture Paramedic. This consists of a foldable plastic square to use in the paddock; a technical manual that steps you through the process as well as containing some excellent pictures of different pasture and weed species to help with identification; plus a notebook for your recordings. You score the perennial grass and clover percentage for each square, as well as classifying the weed type, then average the score over the paddock to give an indication of whether renovation is required. This Tool will be particularly useful for late autumn to spring evaluation of pastures, and it is hoped that Gippsland Ag Group will be able to run some workshops on how to use it soon.

As a rough rule: if the proportion of either improved grasses or clovers falls into the “Good” category, and the other improved species category is present in at least an ”Average” proportion and the weed species present are palatable then it should be possible to manipulate your pasture to improve the quality. This may involve using herbicide to reduce the weed burden of the paddock and oversowing to top up the desirable species; improving soil nutrients including micro-mineralsto promote persistence, and/or changing your grazing management.

If both clovers and improved grasses fall into the average or poor categories; then it is probably necessary to renovate, but if you have any doubt always consult with an agronomist.

If you are planning to renovate a paddock next year, there are two steps you should be taking now to ensure successful establishments of perennials next autumn:

  • Take a soil test (if not done recently) and a plant tissue test
    • Spring is the best time for a plant tissue test to give you the best indication of mineral deficiencies, as plants are actively growing. Spring is an easy time to take a representative sample while avoiding urine or dung patches which may compromise your results
    • A soil test is important. It will provide an indication of where your main macro and micronutrient levels are, the pH level of your paddock, and deficiencies that should be addressed before you go back into permanent pasture
    • If your pH level indicates that you need to apply lime, there may be some benefits from correcting this at the start of the renovation process, particularly if you want to sow phalaris or Lucerne. It often takes 12 to 18 months before the pH starts to change after the addition of lime
    • A study published in 2020 that looked at soil test results across East Gippsland showed that the majority of beef properties sampled had a moderately to strongly acidic soil, low phosphorus and a deficiency in molybdenum and boron. All of these elements are critical for successful survival of perennial pastures. Soil tests and application of the recommended fertiliser regime are a critical step for both restoring and renovating perennial pastures
  • Put in a program to control annual grasses and prevent them seeding. The main grasses of concern locally are annual ryegrass (Wimmera rye) and barley grass, but silver grass, brome grass, bent grass and fog grass are also of concern. Failure to control these now will result in young perennials being out-competed by vigorous annuals after planting, particularly if you work the soil.
    • Options for control include
      1. Spray top where you graze the paddock heavily or cut silage in early spring to remove the seedheads of annual grasses. When the weed seedheads appear spray with a sub-lethal dose of glyphosate, and graze again to prevent any further emergence of seedheads. The timing of the spraytop is critical for success
      2. Spraying out the paddock and putting into a summer crop. Graze heavily, allow 7 – 10 days for the paddock to get some fresh growth on, then you spray it out
  • Utilise cutting for silage or heavy grazing whilst the quality persists and then spray out with a lethal dose of glyphosate once quality deteriorates
  1. Where there is a significant seed burden it is worthwhile controlling annual weeds for 2 years before planting perennials. This may involve planting your paddocks to a cereal crop in the year before you plant (consider the weeds you are addressing and use a crop which will have ‘in crop’ herbicide options, e.g. using a cereal allows you to safely spray a grass selective herbicide to take care of winter grass without killing the cereal

If herbicides are to be used remember to:

  • Check herbicide labels for plant back periods for pasture species if residual herbicides are used.
  • Check herbicide labels for stock withholding periods.
  • Calibrate boom sprays regularly to ensure accuracy of pesticide applications

Gippsland Ag Group are currently running an MLA funded Producer Demonstration Site project to demonstrate best practice methods of establishing and maintaining perennial pastures. As part of this we will be demonstrating control of annual grasses and use of Pasture Paramedic.


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