Mallee Seeps Newsletter 8

MALLEE SEEPS NEWSLETTER

IN THIS ISSUE:

NEWSLETTER NUMBER 8, AUGUST 2021

MALLEE SEEPS IN THE HOME STRAIGHT

MALLEE SEEPS HEADING FOR THE HOME STRAIGHT!

TRIALS PROVE THE TRUE VALUE OF LUCERNE IN MANAGING SEEPS

The Mallee Seeps project is well and truly in the "home straight,"as it now enters the final six months that will see some really exciting project delivery activities put in place and of course key recommendations and strategies to deal with seeps on-farm across the Mallee.

NDVI EXPERIENCES AT COOMANDOOK MONITORING LONG TERM TRIAL SITES TIPS ON SOWING TALL WHEAT GRASS AND PUCCINELLIA

It is hard to believe that the initial planning stages for this project were underway some 5 years ago!

But there is still plenty of work that needs to be done to firstly inform farmers that it is possible to manage seeps, and secondly on the ground action will result in some considerable long-term gains in terms of remediating seep affected landscapes and secondly bringing such land back into productive potential.

The project overall has remained on track in terms of achieving the required activities and outputs from the the research and field extension activities.

Key areas of focus for the final stage of the project is to consolidate all of the field research results and proven management strategies to deal with seeps - and to incorporate all findings into a final project report.

An important element of the project is the commitment by the Mallee Seeps project team to extend as much of the key information, tools and resources arising from the project to farmers - so that practical action on-farm can take place.

This will serve as the final foundation activity for the project, allowing seep affected farmers to have access to the latest best practice management options for managing seeps.

All in a day's work for Seep Project consultant Chris McDonough!

LUCERNE PROVING TO BE A VITAL ALLY IN THE FIGHT AGAINST MALLEE SEEPS!

LUCERNE LIKES DEEP SANDS

"Lucerne is the most effective strategy for drying the profile on seep prone sands" Frontier Farming Researcher Michael Moodie In April 2021, deep soil sampling was undertaken at the

two seeps demonstration sites; these being at Turriff in Victoria and Lameroo in SA. Samples were collected in 25 cm increments down to a depth of 3 m at each site with soil moisture content measured for each sample.

The data clearly showed that the treatments where lucerne was established in 2019 are much drier than the other management tactics implemented at the site (refer to the two graphs featured below).

At Turriff, the soil moisture content on the deep sand to a depth of 3 m was 117 mm which was 67 mm less than the moisture content of 180 mm measured under the other treatments at the site.

Similar results were observed at the Lameroo site. The moisture content under the lucerne treatments was 100 mm in the top 2.5 m soil profile. However the soil moisture content was more than double this under the other treatments where 220 mm was measured in the top 2.5 metres of soil.

Some of the soil samples being collected from the Turriff site, as you can see the soil profile is characteristic of a deep sand.

Picture: Michael Moodie

After two seasons, these trials have shown than lucerne is by far the most effective treatment at preventing recharge on sand dunes.Across two sites, the sites were 67-120 mm drier than corresponding treatments.

This dry profile will provide a buffer against future rainfall events where moisture will be held in the soil profile rather than leaking through soil and finding it way into nearby seeps.

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SOME PRACTICAL LESSONS FROM THE FIELD

MANAGING COVID-19 IMPACTS There is no doubt that Covid

STRAW OVER INEFFECTIVE @PINNAROO (NOW SOWN TO PUCCINELLIA

has had a significant impact on the delivery of the Seeps project, where the major impacts have related to the inability to cross borders and importantly to bring farmers together out in the field.

The project has continued to undertake in paddock trials and demonstrations, which have proven to be extremely beneficial in terms of identifying best bet management practices to help reduce the impact of seeps (with the view of long-term remediation) and to develop a better understanding of why seeps form, and the impact of rain events and in-paddock treatments over seep incidence and severity.

Despite these constraints, the project team has been committed to bringing short videos from the field virtually to farmers, project team members and others interested in seep management.

Everyone is encouraged to continue accessing the Seeps website through the Mallee Sustainable Farming website! https://msfp.org.au/mallee-seeps/

Coor on g Salt lan d Past u r e Redem pt ion Pr oject ou t com es 2020-21

b y Tracey Strugnell

Over 2020-21 the Coorong Saltland Pasture Redemption Project has been generously supported by the Coorong District Council and the Murraylands and Riverland Landscape Board through funding from the Australian Government?s National Landcare Program and the Landscape Levies. This work provides support to land managers impacted by dryland salinity, and to continue to fine tune understanding of the best land management options.

The time of sowing is critical in trying to remediate saline country. To improve the chances of plant germination, a ?flush?of rainfall is thought to be required. In 2017-2018 this ?flush?was not received and there was poor germination across all sites.

In 2019, exceptional germinations were observed across a number of hostile, saline soils. The late time of sowing after the salts had flushed through the soil was thought to be the key difference driving this success. Work done over the 2018 ? 2020 period indicated the effectiveness of the rainfall events in pushing water down through the profile (taking salts with it) by aligning; rainfall events, soil moisture probe data, and saltland pasture germination. This work carried out over the 2020-21 year has continued to build the efficacy of this data.

Vision s f r om t h e f ield

Photos (left to right) Pasture cages on - Shot gun mix, Messina, Puccinellia, and salt tolerant Dryland Lucerne

Have you ch eck ed ou t ou r M allee Seeps pu blicat ion s on t h e M SF Websit e yet ?

MONITORING OF LONG TERM DEMONSTRATION SITES 1

Tracey Strugnell and Felicity Turner Monitoring of key long-term demonstration sites has been continued in 2020-21 with a good start to the 2020 winter assisting in germination and persistence of key species. The winter period was quite dry which may have assisted in reducing water logging (particularly at the Cooke Plains site). By spring there was a large amount of ground cover; in particular of Puccinellia which persisted over the summer period and has responded to early rainfall events in 2021.

Increased amounts of ground cover have been observed over the length of the project. This is particularly evident at the Cooke Plains demonstration site on Gypsum Road. This site has been key in identifying issues and learnings particularly with regard to ground cover, mixed swards and flushing effects. The photos below show the site from 2017 ? 2021 over which time approximately 90% groundc over has been achieved.

Early season observations in 2021 have suggested that the predominant species at the site is now Puccinellia however there is the very occasional Neptune Messina plant germinating. This observation was also made at some of the other sites where Messina which had been observed in previous seasons, had not yet germinated. This may be due to a lack of rainfall and a late start to the season ? this situation and the ability of Messina to persist in these environments continue to be monitored.

Photo descriptions Top left: the site in 2017 Top right: the same site two years later in 2019

Bottom left: 2021 improved groundcover Bottom centre: Puccinellia, seedling pasture in 2021 Bottom right: legume Messina in 2021

ESTABLISHING TALL WHEAT GRASS AND PUCCINELLIA ON SALINE MALLEE SOILS From Rob Sonogan The relative importance of site management when it comes to establishing both tall wheat grass and puccinellia can not be over emphasised.

Over the years many have reported first year failures of establishment after sowing tall wheat grass and puccinellia into saline affected soils. This frustrating experience can however be overcome.

Research that I have carried out over the years has clearly shown the critical need to protect newly sown areas from any grazing for at least 18 months from time of sowing.

The combinations of either dry periods after sowing, or top soil salinities being too high to allow germination to occur in the first season may give the impression of seeding failure.

However when ungerminated seeds were recovered in November periods from such seasons and resown into wetted soils; at least 20% of these successfully germinated and went on to produce healthy plants.

So subsequent Summer and Autumn rains may produce seedlings on areas previously determined ?no success?.

It is considered essential; that no livestock (nor rabbits or hares) , no matter how poor the germination appears after the first Spring, should be allowed into a sown salt-pan. At least 18 months should be the minimum period before stock are allowed back, and even then under closely controlled grazing conditions.

ESTABLISHING PUCCINELLIA (TOP PHOTO) OR TALL WHEAT GRASS IS ALWAYS A CHALLENGE, HOWEVER RISKS CAN BE MINIMISED

BY FOLLOWING SOME SIMPLE STEPS!

M allee Seeps Pr oject M an agem en t m em ber appoin t ed as Kn ow ledge Br ok er t o t h e Dr ou gh t Hu b In it iat ive Congratulations to Tony Randall on his new appointment to the Drought Hub. I'm sure we will hear more about this exciting new Federal Government Initiative in coming months, as Tony leads the project's extension outreach activities across SA! We thank you for your support to the Mallee Seeps project in recent years!

Nor m alised Dif f er en t ial Veget at ive In dex NDVI an d Roby Dow n s M oist u r e Pr obe Dat a from Felicity Turner and Tracey Strugnell These visual observations are supported by spring Normalised Differential Vegetative Index (NDVI) data captured from 30th August to 15th September each year, where the changes show a decline in areas with a low NDVI value. The NDVI reflects the greenness of the area being analysed and low NDVI can be used as a measure of areas of low plant growth (bare or sparse areas). The comparative NDVI maps for 2018 and 2019 are shown below showing a decline in the low NDVI areas (red areas) in 2019 suggesting good levels of ground cover have been achieved .

Germination of new plants or annual species appears to be due to salinity levels being diluted and washed through with winter rainfall events. This is currently being explored further, however at the time of writing this report adequate rainfall had not been received (as shown by no increase in soil moisture at 20 cms at the NBN Roby Downs salinity soil moisture probe.

Gr ou n dcover vs Soil Salin it y

The groundcover that was achieved across all sites in 2019 has also assisted in reducing surface soil salinity levels thought to be through a reduction in heat at the surface and a subsequent reduction in the moisture being wicked to the surface as shown in the 2019 data below..

Soil sampling (0-10cms) in May 2021 showed similar results to those previously seen where the presence of groundcover assisted in reducing the surface soil salinity levels as shown below. These sites will be revisited and resampled once the soil wetting front has increased to further explore the theory of the flushing effect.

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Winter wheat (for ground), millet and Lucerne (background) at the Lameroo site

Low tech seeding puccinellia by hand. Have been successful mid season, after some rain to leach out some surface salt, roughen surface scald, throw seed on top (windy day helps) and then roll or press in.

Has proved successful at numerous sites in 2020 and 2021