Improving feed value of perennial grasses
Timeframe: January 2014 to December 2016
Funding source: Meat and Livestock Australia
Project Coordinator: Karryn Dorrell
Summary
The overall objective of this project was to investigate different ways of improving feed value of perennial grasses in two different rainfall zones and at three different sites within the Jerramungup Shire.
At Site 1 in the mid to low rainfall zone (450 – 350 mm) the aim was to trial a non-traditional perennial sub-tropical grass species (gatton panic). At Site 2 in the high rainfall zone (600-450 mm) the aim was to investigate methods of establishing annual pasture species into long-term kikuyu stands to increase the amount of winter feed generated. The aim at Site 3 (also in the high rainfall zone) was to investigate persistence, pasture yield and pasture quality by establishing legumes into a long-term kikuyu stand.
Overall, the trials highlighted that a combination of species selection, establishment methods and seasonal conditions determined success. Variability between soil types and rainfall zones necessitates locally-base trials.
Project details and outcomes
At the design stage of this project it was decided that no specialty machinery would be used so as to encourage other farmers to try establishing pasture on a paddock scale with existing equipment. Farmers in the trial were willing to make modifications to existing machinery where necessary.
SITE 1: trialling a non-traditional perennial sub-tropical grass species
Location: Brian and Janet Penna
Objectives;
To determine if seeding with a winter cover grass helps to establish Gatton Panic.
To determine if seeding with a soil wetter helps establish Gatton Panic better.
To determine if Gatton Panic could effectively extend the feed period and value of a pasture paddock over a three-year period in either quantity or quality.
Soil type: sand over gravel, consistent across the paddock and extremely prone to water repellence and wind erosion.
Seasonal conditions during establishment (2014): excellent
Results
A winter cover grass (barley) did help to establish Gatton Panic. The Panic grew at the base of each barley plant after it hayed off; the barley plant appearing to provide root and moisture channels.
A soil wetter did not have a significant impact on plant establishment however, the summer of the establishment year was a wet one and different results may occur in drier conditions. In the second year of the trial, the wetter-applied site had higher pasture production yields.
Gatton Panic raised both the quality and quantity of pasture production. It improved digestibility and energy marginally but the biggest gain was in the increased overall bulk yield compared with the annual pasture. It effectively extended the feed period and feed value of the pasture paddock throughout the trial.
SITE 2: investigating methods of establishing annual pasture species into long term kikuyu stands to increase the amount of winter feed generated.
Location: Ross and Rhonda Williams
Objectives:
To determine what seeding method provides the best establishment of alternative pastures into an eight-year-old Kikuyu stand.
To determine which pasture would establish better into kikuyu: oats or serradella.
To determine if a knockdown on the kikuyu followed by soil disturbance would create an environment that entices pre-existing clover in the seed bank to germinate.
Soil type: duplex sandy gravel
Seasonal conditions during establishment (2014): The year was characterised by a late break and a very dry summer.
Results
In both oat and Serradella sown pastures, knife points with double disk openers and press wheels provided the best seedling establishment by far. The wing points seemed to dry the soil out more and although they created an environment with less weed competition there was visibly less moisture in the soil.
Serradella pasture established a better stand than oats.
Soil disturbance did instigate growth of clover seed in the seed bank. The higher the tillage option the more the soil dried out, causing lower germination rates.
SITE 3: investigating persistence, pasture yield and pasture quality by establishing legumes into a long-term kikuyu stand.
Location: Ken and Jan, Paul and Alice Reddington
Objectives:
To determine which pasture species (bladder clover or serradella) is the most persistent species when sown into kikuyu.
To determine which pasture composition would give the highest feed quantity over the life of the trial.
To determine which pasture composition would give the highest feed value.
Soil type: duplex sandy gravel soil, chosen for its ten-year-old stand of kikuyu.
Results:
The most persistent pasture legume species sown into the kikuyu was bladder clover. It was slightly more persistent throughout the year whereas the serradella was predominant during winter months but less so during summer. Both legume species continued to emerge at very good rates in season two (2016) indicating the persistence was relatively good in both species, even though kikuyu was not suppressed in the second year.
The highest feed quantity over the life of the trial was the kikuyu pasture with no companion species. It produced between 1500kg-2000kg/ha higher yield during the summer months than the composite pastures and only 500kg/ha less, in one circumstance, than the composite pastures during winter.
Kikuyu pasture contained the highest quality of feed however, it was only marginally higher in digestible fibre, with little other feed value differences between compositions.