Legacy of eight-year cover cropping on mycorrhizae, soil and plants
2018
García-González, Irene | Quemada, Miguel | Gabriel, José Luis | Alonso-Ayuso, María | Hontoria, Chiquinquirá | Quemada, Miguel [0000-0001-5793-2835] | Gabriel, José Luis [0000-0002-5508-4120] | Hontoria, Chiquinquirá [0000-0002-8089-0327]
Cover crops (CCs) provide ecosystem services to agricultural systems by soil health enhancement. However, the long-term legacy of CCs on arbuscular mycorrhizal fungi (AMF) and subsequent main crop performance is unclear. The main objective of this work was to assess the 8-year legacy of CCs on AMF activity and several soil and plant parameters during a subsequent maize (Zea mays L.) crop. The study was conducted in a field experiment established in 2006 under Mediterranean climate. Winter treatments were fallow and two CCs, barley (Hordeum vulgare L.) and vetch (Vicia sativa L.). We chose four sampling dates during maize development to evaluate the effect of CCs on AMF over time. Compared with fallow treatment, barley CC increased mycorrhizal colonization by 7%, the hyphae length by 39–124%, and AMF spores by 48–87%. However, contrary to expectations, vetch CC did not have any effect on AMF. Overall, earlier sampling dates better displayed treatment differences. Mycorrhizal colonization percentage demonstrated time-sensitive values, whereas other AMF parameters (hyphae length, AMF spores) better maintained treatment differences over time. Mycorrhizal stimulation after barley increased maize shoot P concentration but shoot N was not increased despite the N deficit. Soil water stable aggregates were enhanced by barley CC (25–51% higher than fallow), notably related to the length of hyphae, AMF spores and glomalin content. Promotion of soil aggregation, nutritional state and plant height by CCs did not translate into maize yield increments. The main benefits of introducing CCs were related to the enhancement of soil quality and nutrient supply rather than to an increased yield of the following maize crop.
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