Seed carbon source bolsters crop establishment
Energising soils is helping agronomist Gary White get crops off to a flying start
For agronomist Gary White, the use of liquid carbon soil improvers is as much to do with this season as the following ones.
Improving soil health is a foundation for sustainable crop production, but its effect on immediate profitability shouldn’t be overlooked. “Reduced soil carbon and lower levels of organic matter compromise crop yield. It is therefore important to reverse this trend, to rebuild soil organic mat-ter and promote more efficient nutrient uptake for more profitable and sustainable production,” he says.
“Research has shown that increasing the supply of readily available energy to the soil microbiome stimulates soil biol-ogy, increasing the activity of fungi and protozoa as well as bacteria. Additionally, increasing the supply of carbon will help to improve the soil’s physical and chemical properties.”
A planned approach to improving soil health and crop sustainability starts with boosting soil microbial activity. Soil microbes capture and solubilise nutrients for the plant, so the more effective the microbial populations, the better the nutri-ent supply to the plant.
In a symbiotic arrangement, plants pro-vide carbohydrates and carbon to the soil in the form of root exudates, effectively a sugar/carbon solution for the microbes. The microbes and organic acids increase the rate at which mineral nutrients in the soil are dissolved, increasing their availa-bility to the plant, he explains.
“Plants produce carbohydrates via pho-tosynthesis and any surplus is used for root exudates to feed the soil microbiota. When performing well, a plant will pro-vide 40% of assimilates from photosyn-thesis into the soil via root exudates, con-taining carbon and sugars. Feed the plant with a source of sugar and carbon and it can meet its demand for carbohydrates for growth more efficiently, allowing the production of root exudates to increase.”
He uses the ED&F Man Agronomy liquid carbon range, as it is formulated for soil and foliar application, and because it is filtered to 200 microns, it is suitable for use in the majority of spraying systems. He advises a rate of 1-2 litres/ha, depending on the crop.
Better root development
Gary advises using both soil and foliar applications through the growing season. He says the immediate benefit of soil applications is that it drives root develop-ment, which is advantageous throughout the season.
“By feeding the microbiome around the seed, we are providing a feed and carbon source to increase soil bacteria, which in turn encourages stronger rooting and bet-ter crop establishment. The increased car-bon supply also helps maintain and build carbon levels in the soil.
“Strong rooting can help the plant throughout the season by ensuring better access to water and nutrients. I am seeing evidence of better drought resistance and faster recovery after a period of drought.
“Frost can cause loss of root mass and fewer tillers, but deeper-rooted crops are better able to withstand the effects of frost.”
During the season, foliar applications will continue to supply carbon to the soil, but will also increase the supply of root exudates, which will maintain a higher rate of bacterial activity and greater supply of nutrients back to the plant.
“The increased release of soil minerals is allowing growers to reduce reliance on artificial fertilisers, increasing nitrogen use efficiency and reducing input costs. Over time, as soil carbon increases the workability of soils improves, allowing a reduction in cultivation costs and increasing the timeliness of cultivations.
“As growers strive to improve soil health, it will be important to recognise the need to make changes. Fuelling the symbiotic relationship between plants and soil microbiome is certainly one change that is beginning to deliver benefits, both in the short and longer term,” Gary concludes.
