Conservation agriculture aims to preserve natural resources—soil, water, air—while still making a living with a farm. Farmers love any technology that betters the long-term sustainability of their operation, especially if it also increases their efficiency and income. Now, a group of Mexican agricultural researchers have placed another flagstone in the pathway to efficiency and sustainability, this time using two little bacteria with big names.
Liliana Marquez-Benavidez and her associates at the Michoacan University of Saint Nicholas of Hidalgo in Michoacan, Mexico, studied how Burkholderia cepacia and Gluconacetobacter diazotrophicus bacteria help barley grow well while requiring less nitrogen fertilizer. They reported their findings in the July-December 2016 edition of the journal Investigación Agraria, which the College of Agriculture at the Paraguayan University of Asunción publishes twice-yearly.
Both B. cepacia and G. diazotrophicus are endophytic plant growth-promoting bacteria, meaning they live inside plants and improve their growth symbiotically. Earlier researchers had found that these bacteria boost wheat and corn output, and had even shown that B. cepacia detoxifies the herbicide 2,4-D, allowing B. cepacia-inoculated barley seed to sprout in 2,4-D-contaminated soils that would normally stop barley germination or kill young seedlings.
In the present report, Marquez-Benavidez et al. compared the total biomass accumulated by barley grown with or without bacteria, comparing inoculated plantings grown at 50% recommended nitrogen concentration to bacteria-free barley grown at 0%, 50%, and 100% recommended nitrogen concentration.
They found that either bacterium significantly (yes, statistically) increased the barley’s dry biomass over bacteria-free controls, even the 100% nitrogen class, and that B. cepacia outperformed G. diazotrophicus. These bacteria appear to promote root proliferation and exploration, leading to more efficient nitrogen capture and less nitrogen waste. It remains to be seen whether this benefit extends to other nutrients as well.
The implication—less nitrogen, more barley—sounds like a winning combination to me.
For the full report, see:
Marquez-Benavidez, L., Morales, P.G., Balderas-Leon, I., Moreno, J.V., and J.M. Sanchez-Yañez. 2016. Inoculación de Hordeun vulgare var Armida (cebada) con Burkholderia cepacia y Gluconacetobacter diazotrophicus. Investigación Agraria. 18(2):87-94.