Eco-biological Soil Assessment: Analytical Approaches through Molecular Methods

Introduction Soil organisms facilitate key ecosystem processes such as nutrient cycling and organic matter decomposition, and also influence soil porosity and water infiltration through the production of bacterial polymers and fungal hyphae that hold soil particles together to form aggregates [1, 2]. Rhizosphere microorganisms can greatly influence the ability of a plant to acquire macroand micronutrients. This may occur as a direct consequence of symbiotic associations between plant roots and microorganisms such as arbuscular mycorrhizal fungi, through symbiotic and associative interactions such as the fixation of N2 by the root-associated bacteria Rhizobium spp., Azospirillum, Azotobacter, or Beijerinckia spp. [3], or through trophic interactions, such as the excretion of nutrients by the microbial feeders protozoa and nematodes [4]. Through these interactions, soil organisms powerfully affect crop growth and yield. Soil management strategies should aim to support and enable soil biota to carry out these key ecosystem functions to assure long-term soil fertility and sustained crop production. In order to understand better how soil management practices influence soil biota and their interactions with plant roots, appropriate methods are urgently needed to detect, enumerate and characterize them.