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Soil microbial biomass (SMB-C) is one of the most frequently used parameters for the assessment of soil quality, but no threshold values have ever been proposed. We challenged the problem of a reliable numerical estimation of the SMB-C based on the knowledge of physicochemical soil properties. The aim was to evaluate artificial neural network (ANN) modelling for the prediction of SMB-C from a range of physical and chemical properties. The dataset used is composed of 231 vineyard soils of widely different characteristics and exposed to different temperature and moisture regimes. Each soil was described by ten physicochemical parameters: sand, clay, soil organic matter, total N, C/N ratio, pH, EC, exchangeable Na, active lime and total Cu. The ANN followed the topology: one input layer (1 to 11 nodes), one hidden layer (2 center dot n nodes) and one output node (SMB-C). Each soil sample was validated against the other 230 samples. The ANN model showed a much better fit than the linear model. The divergence between measured and predicted SMB-C was greatly restrained using the nonlinear approach, testifying the ability of the ANN to adapt to the highly variable dataset. The ANN analysis confirmed the primary importance of SOM for SMB-C prediction, being present in all of the best five models with the lowest root mean square relative error and in four out of five models with the lowest root mean square error. The prediction capability of SMB-C by ANN was limited at high SMB-C values, but the method can potentially be improved by expanding the dataset and introducing more parameters regarding soil physical properties and management.

The article is structured in six sections. A first portion is dedicated to the state of the art concerning climatic change and agriculture. Internet available IPCC maps and cartographic documents made by scientific Centres of research were used for illustrating forecasted climatic changes. In Sections 2 and 3, bibliographic evidences were collected for supporting a vegetation and soil co-evolution theory. Humus, soil and vegetation systems are presented at planet level in many synthetic maps. In Sections 4, 5 and 6 the authors discussed the human influence on the soil evolution during the Anthropocene. It appears that humans detected and used the Mull humus systems all over planet Earth for crop production and pasture. Human pressure impoverished these humus systems, which tend to evolve toward Amphi or Moder systems, losing their natural biostructure and carbon content.

The article is structured in six sections. A first portion is dedicated to the state of the art concerning climatic change and agriculture. Internet available IPCC maps and cartographic documents made by scientific Centres of research were used for illustrating forecasted climatic changes. In Sections 2 and 3, bibliographic evidences were collected for supporting a vegetation and soil co-evolution theory. Humus, soil and vegetation systems are presented at planet level in many synthetic maps. In Sections 4, 5 and 6 the authors discussed the human influence on the soil evolution during the Anthropocene. It appears that humans detected and used the Mull humus systems all over planet Earth for crop production and pasture. Human pressure impoverished these humus systems, which tend to evolve toward Amphi or Moder systems, losing their natural biostructure and carbon content.

The introduction of the “subaqueous soils” into the international classification system of the Soil Taxonomy (2010) gives a possibility to soil scientists to use the pedogenetic approach to investigate coastal soils in view of resource protection and valorization. Coastal areas, in fact, are complex and fragile ecosystems whose ecological value is worldwide recognized, but generally highly inhabited and affected by different erosion and pollution phenomena, and flooding problems. The soil science has a great opportunity to contribute to the correct management and protection of coastal soils, by recognizing the value of coastal soils and thus investigating the effect of the water table oscillation and ionic composition to the changes of soil properties and functionality. This work represent a first attempt to describe the soil continuum existing from hydromorphic to subaqueous environment, highlighting the evidence of some pedogenetic processes into subaquatic substrates and demonstrating the high ecological values of these pedons.

The introduction of the “subaqueous soils” into the international classification system of the Soil Taxonomy (2010) gives a possibility to soil scientists to use the pedogenetic approach to investigate coastal soils in view of resource protection and valorization. Coastal areas, in fact, are complex and fragile ecosystems whose ecological value is worldwide recognized, but generally highly inhabited and affected by different erosion and pollution phenomena, and flooding problems. The soil science has a great opportunity to contribute to the correct management and protection of coastal soils, by recognizing the value of coastal soils and thus investigating the effect of the water table oscillation and ionic composition to the changes of soil properties and functionality. This work represent a first attempt to describe the soil continuum existing from hydromorphic to subaqueous environment, highlighting the evidence of some pedogenetic processes into subaquatic substrates and demonstrating the high ecological values of these pedons.

The flooding regime of saltmarshes strongly affects organic matter mineralisation, representing a unique situation where oxygen diffusion is either impeded by submersion or favoured by retreating water in regular cycles within the same day. Decomposition of Limonium vulgare Mill. residues in saltmarsh soils was evaluated measuring CO2 and CH4 emissions. Four different saltmarshes from the Grado Lagoon (Northern Adriatic Sea) were investigated. Soils were characterised by a similar vegetation (Sarcocornietea class) and similar high coverage of L. vulgare (70-75%) but differed in redox potential, texture and organic carbon content. Hydromorphic conditions were reproduced in mesocosms, and soils were 20 incubated under fully aerobic, fully anaerobic and transient (6 hours cycles) tidal states. Partially decomposed litter (leaves) of L. vulgare was added and 22 decomposition processes were monitored through CO2 and CH4 emissions. Larger CO2 emissions were measured under aerobic conditions, in particular in soil samples with coarse texture. Fully anoxic and tidal regimes showed a similar behaviour. On the contrary, CH4 emissions were less dependent upon flooding, showing only slightly larger values under completely submerged conditions. Larger CH4 emissions have been obtained in fine textured soils. Soil organic matter content also influenced gas emissions: larger values corresponded to higher emissions of both CO2 and CH4.