Peck, Gavin, O'Reagain, Joe, Johnson, Brian, Kedzlie, Graham, Mace, Gina, Buck, Stuart, Newman, Louise, O'Connor, Rod, Hall, Trevor, and Taylor, Brad (2017) Improving productivity of rundown sown grass pastures. Volume 4: Improving reliability of establishing legumes into existing grass pastures. Report. Meat and Livestock Australia Limited, Sydney, NSW, Australia.

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Abstract

A major constraint to the successful incorporation of legumes into existing sown grass pastures is the lack of establishment reliability. Legumes like desmanthus, Caatinga stylo,leucaena and medics have been shown to be well adapted and productive in the Brigalow Belt bio-region (Volume 3 of this report) and have been available to graziers for 20+ years. There have been many tons of legume seed sold over multiple decades to graziers in the Brigalow Belt, but very few pastures with a meaningful amount of legumes present to show for the investment. Graziers involved in focus group discussions identified poor establishment as one of the major constraints to the use of legumes with existing sown grass pastures (Peck et al., 2011).

Although good establishment is recognised as critical to the long term productivity and persistence of pasture legumes, most producers use low-cost and low-reliability establishment techniques such as broadcasting out of planes after either no or minimal pasture disturbance (e.g. fire) or one-pass cultivation where seed is sown at the same time or severe soil disturbance and a rough seed bed behind a blade plough used for controlling woody regrowth (Peck et al., 2011). These techniques of introducing legumes have been considered successful in many years in monsoonal areas which have a much higher chance of germinating rain with follow up rain shortly after and less competitive native grasses on less fertile soils but have been woefully inadequate in the vast majority of years with competitive sown grass pastures on fertile soils in the sub-tropics.

Although good establishment is recognised as critical, many producers don’t think they can afford to use more expensive establishment techniques and defer grazing to allow legume establishment. A focus on establishment difficulties and negative short term economic returns by producers needs to be balanced with the opportunities of higher production of legume grass pastures over the long term as demonstrated by research. Despite the opinion expressed by graziers during focus group discussions, economic analysis suggests that spending more money on legume establishment in this environment will provide better returns, especially compared to techniques that have been failing graziers for decades (Peck et al., 2011).

The un-reliable results from commercial sowings of legumes into existing sown grass pastures has led to more reliable establishment techniques being a research priority for this project. The aims of this component of the project were to quantify the impacts of using better agronomic practices for establishing legumes into existing grass pastures.

Sixteen trials were conducted to test different aspects of establishing legumes into existing grass pastures. The trials conducted as part of this project were:

- Two fallow moisture storage trials. These trials aimed to determine how far buffel grass roots extract water into a fallowed strip. Fallowed strips are seen as a way of improving reliability of establishment while reducing overall costs and permitting some grazing during preparation.

- Two seeding rate trials. These trials tested whether increasing seeding rate results in higher numbers of legume plants establishing.

- Six fallowing, seed bed preparation and post-emergence weed control trials. These trials aimed to test the impact of using agronomic practices typically used in the grain industry on legume establishment.

- Six rate of legume spread trials. These trials aim to determine how quickly Caatinga stylo and desmanthus spread into existing grass pastures if they are established in strips.

The results of these trials have shown that establishing small seeded legumes like desmanthus and Caatinga stylo can be a lot more reliable if good agronomic practices are used. Key principles or considerations for reliable legume establishment in existing grass pastures are: - Legume seedling access to moisture and other nutrients. - Good seed to soil contact. - Establishing legumes in strips or across whole paddocks.

Item ID:	82849
Item Type:	Report (Report)
Keywords:	Sown pastures, legume establishment, Caatinga, desmanthus, rundown, brigalow belt, buffel grass, legumes, productivity decline, legume pastures
Copyright Information:	Reproduction in whole or in part of this publication is prohibited without prior written consent of MLA.
Funders:	Meat and Livestock Australia (MLA)
Date Deposited:	17 Jul 2024 23:21
FoR Codes:	30 AGRICULTURAL, VETERINARY AND FOOD SCIENCES > 3004 Crop and pasture production > 300403 Agronomy @ 100%
SEO Codes:	10 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 1005 Pasture, browse and fodder crops > 100505 Sown pastures (excl. lucerne) @ 100%
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