Negative and positive contributions of arbuscular mycorrhizal fungal taxa to wheat production and nutrient uptake efficiency in organic and conventional systems in the Canadian prairie

• Published in: Soil biology & biochemistry 2014-07, Vol.74, p.156-166
• Main Authors: Dai, Mulan, Hamel, Chantal, Bainard, Luke D., Arnaud, Marc St, Grant, Cynthia A., Lupwayi, Newton Z., Malhi, Sukhdev S., Lemke, Reynald
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biochemistry and biology; Biological and medical sciences; Canadian Prairie; Chemical, physicochemical, biochemical and biological properties; Diversity of arbuscular mycorrhizal fungi; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Glomus; Nitrogen efficiency; Organic production; Paraglomus; Phosphorus efficiency; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Soil science; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Triticum aestivum; Wheat
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2014.03.016

Improving technologies and the challenge of producing more bio-products while reducing the environmental footprint of humans are shifting paradigms in agricultural research. Harnessing the microbial resources of arable soils is a new avenue to improve the efficiency of nutrient use in agriculture. The objective of this study was to define how crop management influences the contribution of resident AM fungi to nutrient efficiency and crop productivity. The AM fungal communities of 72 organically and 78 conventionally managed wheat fields of the Canadian prairie were described by 454 pyrosequencing and related to crop productivity and N and P use efficiency. Conventional management reduces soil pH and increases the fluxes of all soil nutrients except S, B, and K. Organic management increased the abundance of Claroideoglomus reads. The efficiency of N and P uptake from soil by organic wheat was 2.3 and 1.8 times higher than that of conventional systems. This high N and P uptake efficiency in organic wheat crops was mainly attributable to the low soil fertility of organic fields, as wheat biomass production was 1.44 times greater in conventional than organic systems. Overall, the amounts of N and P taken up by conventional and organic wheat crops were similar. Plant nutrient balance and the abundance of Paraglomus drove conventional wheat production, whereas organic production depended mainly on soil moisture, plant nutrient balance, and abundance of Glomus, which was associated with reduced and nutrient-inefficient wheat production. The high nutrient concentrations at maturity and the low productivity of organic wheat fit a model of limiting CO2-assimilation. The trade-off between nutrient use efficiency and productivity in low input wheat production could be relieved by reducing the abundance of Glomus species, increasing soil moisture and early N availability, or by improving the inherent CO2 assimilation capacity of wheat. [Display omitted] •Organic management favors Claroideoglomus in the Canadian prairie.•Plant nutrient balance and the abundance of Paraglomus drive conventional wheat production.•Organic wheat nutrition and production are inversely related to the abundance of Glomus.