Infectividad micorrícica nativa en suelos de la Región Pampeana con cultivo de soja, diferentes historiales y características edáficas

(AMF), symbionts of the roots of most higher plants and known to promote host nutrition and growth, and soil sustainability. However, the magnitude of the contribution by the AMFs depends, in part, on maintaining its abundance in the soil and their potential to form mycorrhizae with roots. Our objective was to analyze variations in mycorrhizal infectivity (IMS 50 ) and in spontaneous arbuscular mycorrhizal colonization (AM) of soybean crops cropped at three agricultural sites from the north of the Pampean Region (Córdoba), in relation to the historical land use (Agricultural [soybeans for more than 60 years], Mixed agricultural-livestock [A-G, soybean in the last 35 years], and Sierras [soybean in the last 20 years]). An in vivo bioassay revealed that the highest IMS 50 occurred at the Agricultural and Sierras sites, in relation to the Mixed A-G one, the site with the highest available soil P content. Both the IMS 50 and AM negatively correlated with soil P, while IMS 50 was negatively associated with sand content, and positively with water, carbon and clay content. A high degree of infective potential by native AMF was detected in soils destined for soybean crop at the Pampean Region with different historical land use. The IMS 50 was a more sensitive detection method than the determination of AM colonization in the field. It is concluded that IMS 50 could be used to define agricultural management strategies to maintain/favor native AMF communities.