CHARging soils with carbon
From the edition of Agriculture Today.
CHAR, an unheard of new product being hailed as a possible saviour for Australia’s carbon-depleted soils, is the subject of a NSW Department of Primary Industries (DPI) trial.
'Char is a charcoal-like product that is the residue of a renewable energy production process called pyrolysis,' said NSW DPI senior research scientist Dr Lukas Van Zwieten.
'Char is produced when papermill waste, green waste or other biomass is recycled through controlled pyrolysis burning.
Adding char to soil could improve soil health dramatically and also help reduce the green-house effect through carbon sequestration. That is by putting carbon back into the soil for the long term instead of into the atmosphere.'
Dr Van Zwieten and other scientists at NSW DPI’s Wollongbar Agricultural Institute are conducting preliminary assessments of a paper mill char on crop growth and soil health.
Pot trials using sandy and clay soils will assess the benefits of char, applied at the equivalent of 10 tonnes per hectare, on the growth of radish, wheat and soy-bean, and on the benefits to soil health.
Soil health assessments will include total carbon and nitrogen levels, earthworm and microbial activity, water holding capacity, cation exchange, acidity and nutrient retention.
Dr Van Zwieten said char has the capacity to reverse 150 years of organic matter decline in Australian soils.
'Loss of soil carbon is linked to declining agricultural productivity associated with widespread land degradation and reduction in water quality,' he said.
'Char is claimed to increase agricultural productivity and fertiliser use efficiency by restoring organic carbon and enhancing physical, chemical and biological soil properties.
'But these claims have yet to be tested conclusively.'
He said char may provide an effective means for not only reversing land degradation and improving agricultural productivity but also slowing climate change.
'While the production of green energy has many advantages in itself, use of char as a soil amendment will be the focus of this innovative project,' he said.
'The results will be applicable to a wide range of biomass sources, and many broadacre and intensive industries.
'The anticipated benefits of increased plant production, greater fertiliser efficiency, carbon sequestration and less nutrient and pesticide run-off will have a direct economic benefit to rural industries in regional Australia, and multiple environmental benefits.
Contact: Dr Lukas Van Zwieten, NSW DPI Wollongbar on 02 6626 1126.
- PHIL BEVAN
This story appears in Agriculture Today.