Seed & Chemical
Microrganisms can help crops grow
By Agriculture and Agri-Food Canada
Jan. 16, 2012 - Dr. Chantal Hamel is passionate about organisms humans can’t see with the naked eye.
Her goal is to improve crops by managing tiny microorganisms found in soil and the plants themselves. These organisms have the potential to increase crop yields while allowing for a reduction in the use of fertilizers.
Dr. Hamel, who earned her Ph.D. in crop physiology from McGill University, has performed her research at the Semiarid Prairie Agricultural Research Centre (SPARC) in Swift Current, SK since 2003. Her area of expertise is plant microbiology, the study of how microscopic organisms harm or benefit plants.
The world’s population is now at seven billion and growing and demand for food is growing with it. Farmers use fertilizers to increase yields, but the resources used to make fertilizers - phosphate and fossil fuels - are non-renewable and their use can pose environmental challenges.
“In nature, you have plants that do perfectly well and they aren’t cared for with fertilizer or pesticide,” comments Dr. Hamel. “They are not planted in rows, protected, or irrigated. How come our crops are not more efficient?”
Dr. Hamel is working to answer that question using endophytes, bacteria and fungi that live in the plant without causing disease. Endophytes are diverse, and can potentially stimulate crop growth. Most of them have not yet been identified by scientists, so their full potential remains to be discovered.
Once an endophyte is identified as beneficial, it is called a “plant-growth-promoting microorganism.” Dr. Hamel and her colleagues at SPARC have already identified three types of bacteria with promising results.
When a chickpea plant is stressed due to drought, flooding, disease, or excessive heat, it produces ethylene gas, which hinders growth. However, with the addition of the three bacteria the plants produce less ethylene when they’re stressed, so growth is less likely to slow.
The three bacteria recently discovered by Dr. Hamel and her colleagues are not yet well understood by scientists. There are, however, soil bacteria, such as Rhizobia, that have been studied thoroughly and are well recognized for their contribution to cropping systems. Rhizobia helps legumes, crops such as lentils, chickpeas, and alfalfa, access nitrogen more efficiently, which leads to improved nitrogen levels in soil. This encourages crop growth.
Some scientists suggest using soil inoculants, adding bacteria or fungi to the soil, to improve crop growth. Others, like Dr. Hamel, believe there are plenty of microorganisms already present in the field. We simply need to learn to better manage them.
“Plants are amazing organisms,” said Dr. Hamel. “They can’t walk away when there’s danger so, instead, they produce lots of phytochemicals -- naturally occurring chemical compounds. That’s why lots of medicine comes from plants. They produce different chemicals to repel foes and call upon microbial friends.”
This is why the SPARC wheat breeding program is looking at developing genotypes that have the special ability to benefit from, and multiply beneficial microorganisms in the soil. Farmers wouldn’t have to purchase inoculants to add to the soil because the benefits would already exist in the planted seeds. Similar research is also being conducted using chickpeas.
“Before, it was not necessary to worry beyond fertilizer,” said Dr. Hamel. “But now, we must find something else. Now, we have to think of something new.”