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Can polymer film enhance direct seeding of native vegetation?

New research suggests a positive correlation between the use of degradable polymers and enhanced direct seeding in the Mallee.

Can polymer film enhance direct seeding of native vegetation?

Wemen trial site, June 2014

Trials have been conducted  to assess what influence polymer films may have when used in conjunction with direct sowing of native seeds in the Mallee, with some positive early findings.

The benefits of using polymer films to improve crop outcomes are widely accepted. Extensively used as a mini greenhouse in agricultural production, they are known to provide additional heat to the soil, improve crop propagation, facilitate seed germination, suppress weeds and conserve soil moisture. However, very little research has investigated the effect polymer films have on native seed sowing. Currently, methods for revegetation with native species can be expensive and time consuming, and harsh Mallee environments can lead to low survival rates with direct seeding. Considering the cost of current revegetation methods to landholders and the semi-arid conditions of the Mallee, the use of polymer films when sowing native species was explored in trials to assess their use in revegetation in this region.

Birchip Cropping Group and the Mallee Catchment Management Authority (CMA) delivered trials between 2102 – 2014 to assess the use of biodegradable polymers on direct seeding and revegetation in the Mallee. Four trail sites were established, each in differing rainfall zones and containing different soil and Ecological Vegetation Classes (EVCs), to demonstrate the performance of the polymers under varied environmental conditions. Soil types at the four sites were as follows: Birchip – clay loam; Patchewollock – sand; Wemen – sandy loam; Ned’s Corner – sand. Seeds were sown in different seasons. The effect of the polymer film on germination rates was assessed by counting seeds that had germinated approximately three months after sowing.

Polymer treatment yielded higher germination of native seeds at three of the four trialled sites: Ned’s Corner, Patchewollock and Birchip. These results, while not statistically significant, indicated a positive trend towards the use of polymers in generation of native seeds. Seasonal data suggested that seed sown in cooler seasons had higher germination rates and seedling survival than when sown in warmer seasons.

Unfortunately, atypical weather conditions during the project period affected the trials, hindering a number of conclusive findings. However, these early results do indicate that using polymer film has a positive effect on germination rates of native seeds. Results also show that the ideal time to sow seeds is Autumn, with warm soil temperatures facilitating faster germination and early growth before the harsher Spring and Summer conditions. Further research is recommended.

To learn more about the trials please click here to go to our Technical Bulletin ‘Trialling polymers to enhance direct seeding in the Mallee’.

To view a video on this trial click here

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