Diverse annual plantings and their contribution to forage yield and soil improvement

Non-Peer ReviewedMulti-species plantings, also known as polycultures, are expected to have several ecosystem benefits based on the varying contributions from different plants. Potential benefits include increased nutrient cycling, increased soil moisture retention, increased forage yield, decreased soil compaction, and decreased weed communities. Local Saskatchewan producers and groups have implemented multi-species plantings with great success, and this project attempts to build on this anecdotal evidence to not only quantify the impact of polycultures, but to also determine what makes a mixture more or less effective in a particular environment. Our preliminary results suggest that increased crop species richness and functional group richness have many benefits including increased biomass production and decreased weed and insect abundance

Valedictory Address: Bainard Cowan

Valedictory Address by Bainard Cowan given on May 12, 1970

Reduced diversity of AM fungi in annually cropped fields of the Canadian prairie

Non-Peer ReviewedThe arbuscular mycorrhizal (AM) fungi are important service providers to agriculture that are impacted by certain cultural practices. We assessed the status of AM fungal resources in the Prairie, from the Grey to the Brown soil zone, through sampling 176 wheat fields, 117 adjacent roadsides and 24 natural areas, at heading. The 18S rRNA gene sequences of AM fungi in soil metagenomic DNA accounted for 15% of all fungal target sequences recorded, and clustered in 122 operational taxonomic units (OTUs), a proxy for species. A few OTUs dominated under each land use type, and these OTUs often dominated under all three types of land use. The AM fungal community was influenced by land use and soil type. The size of the family Claroideoglomeraceae decreased from Black to Brown soils, and from roadside to field soil. On average, about eight OTUs were found in a field or a natural soil as compared to 14 in roadsides, and diversity (Shannon index) was lowest in cropland where the community was very uneven. The diversity and abundance of AM fungi was low in Brown soils. Lower AM fungal abundance and diversity in 2009, the dry year, than in 2010, the wet year, suggests that the proliferation of AM fungi in Brown soils may be limited by water availability. A long history of frequent fallow and wheat monoculture in the Brown soil zone may also explain reduced AM fungal diversity in these dry soils

Phosphorus forms and concentrations in soils under different land use in southwestern Saskatchewan

Non-Peer ReviewedPhosphorus (P) is an essential nutrient for all organisms. Insufficient or poorly available P can limit crop growth, requiring P fertilization. However, excess P can move from land to water, impairing water quality. Balancing P fertilization to maximize crop growth while limiting P loss requires a detailed knowledge of P forms and cycling. Different land use practices are expected to alter P cycling through differences in microbial populations, P inputs from vegetation and fertilizer, and management practices that affect soil chemical and physical properties. Understanding P cycling under different land uses can help to improve P use efficiency in agriculture. Presented here are the preliminary results of a research project investigating P forms and cycling in soils under different land uses in southwestern Saskatchewan

Agronomic practices influence soil biodiversity with strong feedback to plant growth

Non-Peer Reviewe

Forecasting the quality of AMF communities

Non-Peer Reviewe

Bases for the management of the AM symbiosis in cropping systems of the prairie

Non-Peer Reviewe

Determining a minimum detection threshold in terminal restriction fragment length polymorphism analysis

Terminal restriction fragment length polymorphism (T-RFLP) analysis is a common technique used to characterize soil microbial diversity. The fidelity of this technique in accurately reporting diversity has not been thoroughly evaluated. Here we determine if rare fungal species can be reliably detected by T-RFLP analysis. Spores from three arbuscular mycorrhizal fungal species were each mixed at a range of concentrations (1%, 10%, 50%, and 100%) with Glomus irregulare to establish a minimum detection threshold. T-RFLP analysis was capable of detecting diagnostic peaks of rare taxa at concentrations as low as 1%. The relative proportion of the target taxa in the sample and DNA concentration influenced peak detection reliability. However, low concentrations produced small, inconsistent electropherogram peaks contributing to difficulty in differentiating true peaks from signal noise. The results of this experiment suggest T-RFLP is a reproducible and high fidelity procedure, which requires careful data interpretation in order to accurately characterize sample diversity