Influence of pulse crops on abundance of arbuscular mycorrhizal fungi in a durum-based cropping system

Abstract

Pulses are an important component in crop rotations in southern Saskatchewan. Besides their capability to fix nitrogen, pulse crops establish a strong symbiotic relationship with arbuscular mycorrhizal (AM) fungi, which have been shown to increase nutrient and water uptake through hyphal extensions in the soil. Incorporating strongly mycorrhizal crops in a rotation may increase inoculum levels in the soil and benefit the growth of a subsequent crop. The objective of this study was to determine if AMF colonization of a durum crop is significantly affected by cropping history and to assess the impact of pulses in crop rotations on the abundance of AMF communities in the soil. In 2004 and 2005, soil and root samples were taken on durum with preceding crops of chickpea, pea, lentil, canola, and durum. Arbuscular mycorrhizal colonization was significantly lower in durum roots following canola in both years. Phospholipid fatty acid analysis (PLFA) was completed to analyze the relative abundance of AMF, saprophytic fungi, and bacteria in the soil. These results demonstrated that although previous crop may play a role in microbial community structure, it is not the only influencing factor.