Lupinus polyphyllus Lindl. and Rumex acetosella L. effects on nutrient accumulation and microbial activity on tephra from the Puyehue–Cordón Caulle eruption (2011)

This study investigated the capacity of Lupinus polyphyllus (Leguminosae) and Rumex acetosella (Polygonaceae) to promote nutrient accumulation and microbial activity on tephra from the volcanic eruption of the Chilean Puyehue–Cordon Caulle complex (Northern Patagonia) in June 2011. In December 2015, February 2016 and September 2016, we sampled (1) barren substrate (‘Barren’), (2) substrate under R. acetosella (‘R. ac. substrate’), (3) substrate under L. polyphyllus (‘L. po. substrate’), (4) R. acetosella rhizosphere substrate (‘R. ac. rhizosphere’) and (5) L. polyphyllus rhizosphere substrate (‘L. po. rhizosphere’) (n = 5). Soil properties (moisture, pH, electrical conductivity, organic C, available P, inorganic N and total N) and microbial activity (enzymatic activities) were assessed. ‘Barren’ presented the lowest moisture, organic C, total N and enzymatic activities. ‘R. ac. substrate’ and ‘L. po. substrate’ showed similar levels of organic C (0.23–0.30 g kg−1), and however, R. acetosella was associated with lower inorganic N (‘R. ac. substrate’ = 0.7 and ‘L. po. substrate’ = 2.3 mg kg−1) while L. polyphyllus tended to promote higher total N, especially in the rhizosphere (‘R. ac. rhizosphere’ = 0.19 and ‘L. po. rhizosphere’ = 0.34 g kg−1). ‘L. po. substrate’ and ‘L. po. rhizosphere’ presented the highest enzymatic activities. After five years, L. polyphyllus and R. acetosella have increased tephra organic C, total N and microbial activity, and however, L. polyphyllus has maintained the best substrate N availability. in Spanish is available with online material. Resumen En este trabajo investigamos la capacidad de Lupinus polyphyllus (Leguminosae) y Rumex acetosella (Polygonaceae) para promover la acumulación de nutrientes y la actividad microbiana en tefra proveniente de la erupción del complejo volcánico chileno Puyehue–Cordón Caulle (Patagonia Norte), ocurrida en Junio de 2011. En Diciembre 2015, Febrero 2016 y Septiembre 2016 muestreamos (i) sustrato sin cubierta vegetal (“Ceniza desnuda”), (ii) sustrato con cobertura de R. acetosella (“R. ac. Sustrato”), (iii) sustrato con cobertura de L. polyphyllus (“L. po. Sustrato”), (iv) sustrato rizosférico de R. acetosella (“R. ac. rizósfera”) y (v) sustrato rizosférico de L. polyphyllus (“L. po. rizósfera”) (n = 5). Se estudiaron los parámetros del suelo (humedad, pH, conductividad eléctrica, C orgánico, P disponible, N inorgánico y N total), y la actividad microbiana (actividades enzimáticas). “Ceniza desn