Mycorrhizal Atriplex nummularia promote revegetation and shifts in microbial properties in saline Brazilian soil

Abstract

Soil microbial attributes are the most sensitive indicators of changes in soil quality caused by land use. The restoration of areas with salinity and sodicity problems via revegetation has a significant impact on soil attributes. Understanding the response of microbial indicators is essential to maintain the bioavailability of soil organic matter and provides an alternative to land reclamation. Therefore, the objective of this study was to evaluate the efficiency of revegetation on the regeneration of saline soil in a Brazilian semiarid area through evaluating the presence of arbuscular mycorrhizal fungi (AMF) and changes in the soil microbial structure and chemical attributes. A field experiment was performed with a randomized block design of eight treatments: a control (without plant cultivation), monocultures (Atriplex nummularia [Atri], Mimosa caesalpiniifolia [Sab], Leucaena leucocephala [Leu], and Azadirachta indica [Neem]), and intercrops (Atri and Sab, Atri and Neem, and Atri and Leu). Soil composite samples were collected from each plot during the dry and rainy seasons when the plants had completed 24 and 30 months of growth after transplanting, respectively. The cultivation of the saline soil allowed an increase in microbial biomass carbon in both seasons. In the rainy season, the soil basal respiration and metabolic quotient were lower in the cultivated area than in the control area. Spore density and mycorrhizal colonization were higher in the cultivated area than in the control area in both seasons. We provide the first data related to the beneficial effects of revegetation with naturally mycorrhized plants of A. nummularia in monoculture or intercrop on the soil quality of a semiarid area.