Visual assessment of the impact of agricultural management practices on soil quality

The intensification of agricultural practices to increase food and feed outputs is apressing challenge causing deterioration of soil quality and soil functions. Such achallenge demands provision of empirical evidence to provide context-sensitive guid-ance on agricultural management practices (AMPs) that may enhance soil quality.The objectives of this study are to identify the most promising AMPs (and their com-binations) applied by farmers with the most positive effects on soil quality and toevaluate the sensitivity of the soil quality indicators to the applied AMPs. The effectof selected AMPs on soil quality was assessed using a visual soil assessment tool ina total of 138 pairs of plots spread across 14 study site areas in Europe and Chinacovering representative pedo-climatic zones. The inventory and scoring of soil qual-ity were conducted together with landowners. Results show that 104 pairs show apositive effect of AMPs on soil quality. Higher effects of the AMPs were observedin lower fertile soils (i.e., Podzols and Calcisols) as opposed to higher fertile soils(i.e., Luvisols and Fluvisols). For the single use applications, the AMPs with positiveeffects were crop rotation; manuring, composting, and no-tillage; followed by organicagriculture and residue maintenance. Cluster analysis showed that the most promis-ing combinations of AMPs with the most positive effects on soil quality are composedof crop rotation, mulching, and min-till. The agreement between scientific skills andempirical knowledge in the field identified by the farmers confirm our findings andensures their applicability

Restoration of nitrogen cycling community in grapevine soil by a decade of organic fertilization

Traditional intensive agricultural practices negatively impact soil quality, leading to increased erosion in the Mediterranean region. In contrast, sustainable management practices that have utilized organic fertilization over a decade improved soil quality in the Spanish "Pago Casa Gran" vineyard, Valencia. Grape prunings, combined with sheep manure or leguminous cover, have improved soil chemical and biological parameters, such as organic carbon, nitrogen content, respiration, PLFA, total DNA and aggregation, however, there has been a lack of information on their effect on specific functional microbial groups. The nitrogen cycling community of the soil was investigated by quantification of genes involved in key pathways, in particular nitrogen fixation, denitrification and nitrification. The abundances of bacterial nifH, nosZ, nirS and nirK genes significantly increased under a decade of organic fertilization when compared to inorganic fertilization, and was linked to increased soil organic carbon. The abundance of nifH was lower where fertilizers rich in ammonia and nitrate were used and its increase under organic fertilization was more related to the availability of organic carbon than to the nature of the organic amendment. Archaeal amoA abundance did not correlate with the type of fertilization and the bacterial amoA abundance was more dependent on the availability of soluble nitrogen than on the type of management. An increase in nosZ under organic fertilization may suggest a greater abundance of denitrifiers with the ability to reduce nitrous oxide to nitrogen gas, reducing greenhouse gas emission. Our results indicate that soil microbial communities involved in biological nitrogen cycling, in particular nitrogen fixation and denitrification, are more abundant under management practices that include organic fertilization when compared to traditional agricultural practices. It may therefore be recommended that organic fertilization be utilized in agricultural systems to assist with sustaining healthy soils

The impact of post-fire salvage logging on microbial nitrogen cyclers in Mediterranean forest soil

Forest fires are a regular occurrence in the Mediterranean basin. High severity fires and post-fire management can affect biological, chemical and physical properties of soil, including the composition and abundance of soil microbial communities. Salvage logging is a post-fire management strategy, which involves the removal of burnt wood from land after a fire. The main objective of this work was to evaluate the impact of post-fire salvage logging and microaggregation on soil microbial communities, specifically on the abundance of nitrogen cyclers and, thus, the potential of the soil for microbial nitrogen cycling. The abundance of nitrogen cyclers was assessed by quantification of microbial nitrogen cycling genes in soil DNA, including nifH (involved in nitrogen fixation), nirS/K and nosZ (involved in denitrification), amoA-B and amoA-Arch (involved in bacterial and archaeal nitrification, respectively). It was demonstrated that salvage logging reduced bacterial load post-fire when compared to tree retention control and resulted in significant changes to the abundance of functional bacteria involved in nitrogen cycling. Microbial gene pools involved in various stages of the nitrogen cycle were larger in control soil than in soil subjected to post-fire salvage logging and were significantly correlated with organic matter, available phosphorous, nitrogen and aggregate stability. The microaggregate fraction of the soil, which has been associated with greater organic carbon, was shown to be a hotspot for nitrogen cyclers particularly under salvage logging. The impact of post-fire management strategies on soil microbial communities needs to be considered in relation to maintaining ecosystem productivity, resilience and potential impact on climate change

Plant species influence on soil microbial short-term response after fire simulation

Plant species can influence fire intensity and severity causing different immediate and long-term responses on the soil microbial community. The main objective of this work was to determine the role of two representative Mediterranean plant species as soil organic matter sources, and to identify their influence on microbial response before and after heat exposure. A laboratory heating experiment (300 A degrees C for 20 min) was performed using soil collected under Pinus hallepensis (PIN) and Quercus coccifera (KER). Dried plant material was added before heating for a total of six different treatments: non-heated control samples amended with the original plant material (PIN0 and KER0); PIN samples heated with pine (PINp) or kermes oak litter (PINk); KER samples heated with kermes oak (KERk) or pine litter (KERp). Heated soils were inoculated with the original fresh soil and different microbial parameters related to abundance, activity and possible changes in microbial community composition and chemical soil parameters that could be conditioning microbial response were measured for 28 days after inoculation. The effect of heating on the soil microbial parameters studied was influenced to a small extent by the plant species providing fuel, being evident in soil samples taken under pine influence. Nevertheless heating effect showed marked differences when plant species influence on soil origin was analyzed. In general, samples taken under pine appear to be more negatively affected by heating treatment than samples collected under kermes oak, highlighting the importance of vegetation as a fresh organic matter source in soil ecosystems before and after fire

Soil microbial recolonisation after a fire in a Mediterranean forest

The capacity of different microbial groups to recolonise soil after a fire event will be decisive in determining the microbial community after the fire. Microbial recovery after a wildfire that occurred in Sierra la Grana (Alicante province, southeast Spain) was tracked for 32 months after the fire. Colony forming units (CFUs) of different microbial groups, microbial biomass, soil respiration, bacterial growth (leucine incorporation) and changes in the microbial community structure (phospholipid fatty acid (PLFA) analysis) were determined directly after the fire and four times during the recovery period. Direct effects were reflected by low values of most microbiological variables measured immediately after the fire. Microbial biomass increased during the first year after the fire but was below the unburned reference site 32 months after the fire. Bacterial activity and soil respiration showed the highest values immediately after the fire, but decreased to values similar to that of the unburned reference site or even lower (respiration) 32 months after the fire. Colony forming units of bacterial groups estimated by the plate count method peaked 8 months after the fire, but then decreased, showing values similar to the unburned reference site at the end of the study, with the exception of spore formers, which were 20 times higher than the reference site 32 months after the fire. Fungal CFUs were more sensitive to the fire and recovered more slowly than bacteria. Fungi recovering less rapidly than bacteria were also indicated by the PLFA pattern, with PLFAs indicative of fungi being less common after the fire. The recovery of microbial biomass and activity was mirrored by the initially very high levels of dissolved organic carbon being consumed and decreasing within 8 months after the fire. The wildfire event had thus resulted in a decrease in microbial biomass, with a more bacteria-dominated microbial community

Assessment of promising agricultural management practices

iSQAPER project - Interactive Soil Quality Assessment in Europe and China for Agricultural Productivity and Environmental Resilience - aims to develop an app to advise farmers on selecting the best Agriculture Management Practice (AMPs) to improve soil quality. For this purpose, a soil quality index has to be developed to account for the changes in soil quality as impacted by the implementation of the AMPs. Some promising AMPs have been suggested over the time to prevent soil degradation. These practices have been randomly adopted by farmers but which practices are most used by farmers and where they are mostly adopted remains unclear. This study is part of the iSQAPER project with the specific aims: 1) map the current distribution of previously selected 18 promising AMPs in several pedo-climatic regions and farming systems located in ten and four study site areas (SSA) along Europe and China, respectively; and 2) identify the soil threats occurring in those areas. In each SSA, farmers using promising AMP's were identified and questionnaires were used to assess farmer's perception on soil threats significance in the area. 138 plots/farms using 18 promising AMPs, were identified in Europe (112) and China (26).Results show that promising AMPs used in Europe are Crop rotation (15%), Manuring & Composting (15%) and Min-till (14%), whereas in China are Manuring & Composting (18%), Residue maintenance (18%) and Integrated pest and disease management (12%). In Europe, soil erosion is the main threat in agricultural Mediterranean areas while soil-borne pests and diseases is more frequent in the SSAs from France and The Netherlands. In China, soil erosion, SOM decline, compaction and poor soil structure are among the most significant. This work provides important information for policy makers and the development of strategies to support and promote agricultural management practices with benefits for soil quality.info:eu-repo/semantics/publishedVersio

Promising Agricultural Management Practices and Soil Threats in Europe and China

Advising farmers on the best agricultural management practices (AMP) to be adopted in order to sustain agricultural productivity while improving soil quality is mandatory to assure future food production. Some promising AMPs have been suggested over the time to prevent soil degradation. These practices have been randomly adopted by farmers but which ones are mostly used by farmers and where they have been applied remains unclear. As part of the iSQAPER project—Interactive Soil Quality Assessment in Europe and China for Agricultural Productivity and Environmental Resilience—we (1) mapped the current distribution of previously selected 18 promising AMPs in several pedoclimatic regions and farming systems along Europe and China, based on ten and four study site areas (SSA), respectively; and (2) identified the soil threats occurring in those areas. In each SSA, farmers using promising AMPs were identified and questionnaires were used to assess farmer’s perception on soil threats in their fields. For this study, 138 plots/farms were identified in Europe (112) and China (26). Results show that most widely used promising AMPs in Europe are crop rotation (15%), manuring and composting (15%), and min-till (14%), whereas in China are manuring and composting (18%), residue maintenance (18%), and integrated pest and disease management (12%). In Europe, soil erosion is the main threat in agricultural Mediterranean areas, while soil-borne pests and diseases are more frequent in the SSAs from France and the Netherlands. In China, soil erosion, SOM decline, compaction, and poor soil structure are among the main farmers’ concerns. This research provides relevant information for policy-makers and the development of strategies to support and promote agricultural management practices with benefits for soil quality

Changes in Soil Microbial Community Structure Influenced by Agricultural Management Practices in a Mediterranean Agro-Ecosystem

Agricultural practices have proven to be unsuitable in many cases, causing considerable reductions in soil quality. Land management practices can provide solutions to this problem and contribute to get a sustainable agriculture model. The main objective of this work was to assess the effect of different agricultural management practices on soil microbial community structure (evaluated as abundance of phospholipid fatty acids, PLFA). Five different treatments were selected, based on the most common practices used by farmers in the study area (eastern Spain): residual herbicides, tillage, tillage with oats and oats straw mulching; these agricultural practices were evaluated against an abandoned land after farming and an adjacent long term wild forest coverage. The results showed a substantial level of differentiation in the microbial community structure, in terms of management practices, which was highly associated with soil organic matter content. Addition of oats straw led to a microbial community structure closer to wild forest coverage soil, associated with increases in organic carbon, microbial biomass and fungal abundances. The microbial community composition of the abandoned agricultural soil was characterised by increases in both fungal abundances and the metabolic quotient (soil respiration per unit of microbial biomass), suggesting an increase in the stability of organic carbon. The ratio of bacteria:fungi was higher in wild forest coverage and land abandoned systems, as well as in the soil treated with oat straw. The most intensively managed soils showed higher abundances of bacteria and actinobacteria. Thus, the application of organic matter, such as oats straw, appears to be a sustainable management practice that enhances organic carbon, microbial biomass and activity and fungal abundances, thereby changing the microbial community structure to one more similar to those observed in soils under wild forest coverage