Improving P-efficiency in Crops Through the Management of Highly Effective Beneficial Soil Microorganisms

Arbuscular mycorrhizal fungi (AMF) forms a symbiosis with 80% of plant species. Plants benefit from association with AMF by enhanced phosphorus (P) absorption and they supply photosynthetically produced carbon substrate to AMF as a food source for the fungi. The objectives of this research initiative are to assess the effects of using a commercial AMF inoculant (trade name MYKE®PRO) containing a reported superior AMF strain sold for field crops since 2011, compared to indigenous AMF fungi in the uninoculated treatments. Variable effects of MYKE®PRO on commercial crop yields have been reported in the Prairie farming community, but the value of MYKE®PRO in field crops has rarely been appropriately assessed through independent tests. In our study, the effects of MYKE®PRO on nutrients (N and P) absorption, crop yield and microbial diversity, and its persistence in pulse-based rotation systems are being examined in 2-year crop sequence experiments. Trials are conducted on P-deficient soils, on two experimental farms, in Swift Current, Saskatchewan and Beaverlodge, Alberta, and on two commercial organic farms in the Swift Current area. These trials also test the value of fertilizing materials and the interaction between MYKE®PRO and fertilization. Inoculation with MYKE®PRO or a sterilized inoculant at five different fertilization levels (0%, 75%, and 150% of the recommended rate of P), in the forms of composted manure, finely ground rock phosphate, and commercial mono ammonium phosphate fertilizer had been applied to the pulse phase of the rotations at the two AAFC Research Stations. The organic farms had only composted manure and rock phosphate.

In summer 2016, inoculation with AGTIV had no significant effect on the subsequent flax yield on both research farms, just as it had no effect on the yield of pulses in 2015, and repeating inoculation in both rotation phases was not better. An incompatibility of AGTIV with local soil biotic or abiotic condition may limit the function of AGTIV at these sites. Weather conditions were much better in summer 2016 than in summer 2015, which was extremely dry in Southwest Saskatchewan and excessively wet in Beaverlodge. The agronomic data, including crop density, crop biomass, crop yield, and plant nitrogen (N), P, potassium (K) and carbon (C) content at blooming stage, and soil moisture and N and P concentrations in spring at different depths have been collected and analyzed. However, the N, P, K, and C content of seed and straw at maturity and soil N and P concentrations in fall are still being determined. Soil microbial analyses are also in progress.