UBC Earth and Environmental Sciences Assistant Professor Craig Nichol explains the soil science behind an agricultural greenhouse gas research program.
By Elnora Larder
Scientists from the University of British Columbia’s Okanagan campus have obtained a grant from Agriculture Canada to determine the best way to water and fertilize crops in order to increase yields while reducing greenhouse gas emissions.
“I think it’s great,” says BC Fruits Growers Association president Kirpal Boparai. “The agriculture industry needs that kind of help.”
“It’s great to see government coming up with these kinds of programs to help growers,” he adds. “Our agriculture budget in B.C. is very low, and government needs to look at that.”
The $1.2 million grant will support research on grapes, apples, and raspberries. UBCO biologists Melanie Jones and Louise Nelson, and soil scientist Craig Nichols won the grant to carry out research on crops and Green House Gases (GHG’s).
In future, there may be shortages of both water and fertilizer. Already, fertilizer is in limited supply and is frequently tied to the availability of fossil fuels. Due to the effects of climate change, there may be water shortages. Growers who know how to get good crop yields in these limited conditions will have an advantage.
“Production of crop volume relies upon delivering both water and nutrients to the plants in the right amounts, and at the right times during the growing cycle,” says Nichol. “Delivering too much water, or too much fertilizer, may result in the leaching of nutrients past the root zone and down to the underlying groundwater.”
According to Jones, roughly half of the greenhouse gases thought to be produced by agriculture in Canada, originate from soil processes involved in the generation by soil microorganisms of three important GHG’s: C02(carbon dioxide), N2O,(nitrogen dioxide) and CH4(methane). Part of the project will include measuring these at different water levels and fertilization rates.
“Practices to improve the efficiency of agricultural water use, such as application of mulches and supplying water based plant need, are being adopted, but the effects of these practices on release or greenhouse gasses are poorly studied,” Jones says.
Plants use carbon dioxide, and can fix it in the soil so it is lost from the atmosphere even when roots die. This is called “carbon sequestration”. The project will measure which management practices increase carbon sequestration.
Nitrous oxide emissions make particularly powerful GHG’s, with a 300-fold higher potential for trapping heat in the atmosphere than carbon dioxide. Two kinds of nitrogen cycling soil organisms produce nitrous oxide: the nitrifying and denitrifying soil organisms. Denitrifying organisms favor saturated soils with limited oxygen availability, while nitrifying organisms like drier soils.
“Irrigation practices, nitrogen fertilizer and mulch application can all have a major impact on nitrification and denitrication activity in agricultural soils,” says Nelson.
She says the project will measure the numbers and activities of the soil microbes and relate them to nitrous oxide emissions. This will help to determine which management practices are effective in minimizing nitrous oxide emissions.
Ultimately, the researchers hope that the knowledge gained from the project will provide growers with climate data so they can calculate the right amount of dissolved nutrients and irrigation water (also known as fertigation) to treat row plants.
The project was is being funded through Agriculture Caanda’s $27-million Agricultural Greenhouse Gases Program, which focuses on developing on-farm greenhouse gas mitigating technologies.
The AGGP is part of Canada’s contribution to the Global Research Alliance, an international group with over 30 signatory countries.