Seed coating for water repellent soils
WA growers could benefit from promising research into a cost-effective seed coating technology which has the potential to boost cereal crop germination rates in water repellent soils.
Recent results from a trial with Grains Research and Development Corporation (GRDC) and the State government investment found that seed coating with wetters provided higher agronomic efficiency than using the current method of placing wetters on top of, or in, the furrow.
Department of Primary Industries and Regional Development (DPIRD) development officer Geoff Anderson presented the findings at the 2018 GRDC Grains Research Update, Perth, earlier this year.
“The seed coating contains a surfactant that reduces the surface tension of the water and can improve germination by improving wetting of the seeding zone,” Dr Anderson said.
“Seed coatings with wetters applied at 0.065-0.325 litres per hectare achieved similar increases in plant density, tiller number, biomass and nutrient uptake as wetters applied to the furrow at 1-5L/ha.
“The large responses in crop establishment, early growth and nutrient uptake observed in these experiments were due to the very dry May-June seasonal conditions and also because the experiments were sown dry.
“These results demonstrate the potential value of this technology to growers on the 10 million hectares of agricultural land estimated to be affected by water repellent soils across southern Australia.”
At the trial site at Darkan, Dr Anderson said the seed coated with soil wetter produced 34 per cent higher plant densities on average than the control with no treatment.
He said, in comparison, both of the soil-applied banded soil wetter treatments – in-furrow and on top of the furrow – averaged 47pc higher plant densities than the control plots, but these used much higher rates of wetters (at 1-5L/ha) than the seed coating treatments and were therefore less cost effective.
At the Darkan site, in-furrow placement of wetters gave a 9pc grain yield response.
Wetter coated to the seed at 4L/t, and the wetter on top of furrow at 5L/ha also increased barley grain yield by 9pc.
At Badgingarra, the commercial soil-applied wetting agents also led to the highest plant growth, measured by tiller number.
The soil wetter, banded at 5L/ha on the top of the furrow, produced plants with the highest number of tillers (at 101 tillers/square metre), which was 130pc higher than the control (44 tillers/m2).
The treatment with seed wetter coated on the seed resulted in only slightly fewer tillers (between 70 and 92 tillers/m2), representing an increase in tiller numbers of more than 100pc compared to the control.
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