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

Relationships between soil water repellency and microbial community composition under different plant species in a Mediterranean semiarid forest

Soil water repellency (SWR) can influence many hydrological soil properties, including water infiltration, uneven moisture distribution or water retention. In the current study we investigated how variable SWR persistence in the field is related to the soil microbial community under different plant species (P. halepensis, Q. rotundifolia, C. albidus and R. officinalis) in a Mediterranean forest. The soil microbial community was determined through phospholipid fatty acids (PLFA). The relationships between microbiological community structure and the soil properties pH, Glomalin Related Soil Protein (GRSP) and soil organic matter (SOM) content were also studied. Different statistical analyses were used: Principal Component Analysis (PCA), ANOVA, Redundancy Analysis and Pearson correlations. The highest concentrations of PLFA were found in the most water repellent samples. PCA showed that microorganism composition was more dependent of the severity of SWR than the type of plant species. In the Redundancy Analysis, SWR was the only significant factor (p<0.05) to explain PLFA distributions. The only PLFA biomarkers directly related to SWR were associated with Actinobacteria (10Me16:0, 10Me17:0 and 10Me18:0). All the results suggest that a strong dependence between SWR and microbial community composition.Ministerio de Ciencia e Innovación CGL2010-21670-C02-0

Temporal characterisation of soil-plant natural recovery related to fire severity in burned Pinus halepensis Mill. forests

Despite Mediterranean ecosystems' high resilience to fire, both climate and land use change, and alterations in fire regimes increase their vulnerability to fire by affecting the long-term natural recovery of ecosystem services. The objective of this work is to study the effects of fire severity on biochemical soil indicators, such as chemical composition or enzymatic activity, related to time after fire and natural vegetation recovery (soil-plant interphase). Soil samples from three wildfires occurring 3, 15 and 21 years ago were taken in the south-eastern Iberian Peninsula (semiarid climate). Sampling included three fire severity levels in naturally regenerated (and changing to shrublands) Pinus halepensis Mill. forests. In the short-term post-fire period, phosphorus concentration, electrical conductivity and urease activity were positively linked to fire severity, and also influenced β-glucosidade activity in a negative relationship. During the 15–21-year post-fire period, the effects related to medium-high fire severity were negligible and soil quality indicators were linked to natural regeneration success. The results showed that most soil properties recovered in the long term after fire (21 years). These outcomes will help managers and stakeholders to implement management tools to stabilise soils and to restore burned ecosystems affected by medium-high fire severity. Such knowledge can be considered in adaptive forest management to reduce the negative effects of wildfires and desertification, and to improve the resilience of vulnerable ecosystems in a global change scenario.This study was supported by a grant for research initiation provided by the Excma. Diputación Albacete (DIPU4-AB2015) and by the funds provided by University Castilla-La Mancha to the Forest Ecology Research Group.The authors with to thank the Spanish Institute for Agricultural and Food Research and Technology (INIA) for the funding awarded through National Research Projects GEPRIF (RTA2014-00011-C06)

La repelencia al agua inducida por el fuego está controlada por pequeñas variaciones en las propiedades del suelo

Fire induced soil water repellency (WR) is controlled by many different factors (temperature reached, amount and type of fuel, etc.). Soil properties may determine the occurrence and intensity of this property in burned soils. The objectives of this paper are to make advances in the study of soil properties as key factors controlling the behaviour of fire-induced WR, and to study the impact of pre-fire SOM content and SOM quality in fire-induced soil WR. In this research, experimental laboratory burnings were carried out using soil samples from different sites with different lithologies, soil types and plant species. Soil samples from the same site differ only in quantity and quality of soil organic matter, as they were collected from under different plant species. All soil samples were heated in a muffle furnace at 200, 250, 300 and 350 ºC without the addition of any fuel load. WR was measured using the water drop penetration time test (WDPT). The results showed significant differences between soil types and plant species, indicating that small differences in soil properties may act as key factors controlling the development and persistence of WR reached, with burned soil samples ranging from wettable to extremely water repellent. The main soil property controlling the response was texture, specifically sand content. The quality of organic matter was also observed to have an effect, since soil samples from the same site with similar organic matter contents, but collected from beneath different plant species, showed different WR values after burningLa repelencia al agua (WR) inducida por el fuego es una propiedad controlada por muchos factores diferentes (temperaturas alcanzadas, cantidad y tipo de combustible, etc.). Algunas propiedades del suelo pueden determinar la presencia y la intensidad de esta propiedad en los suelos quemados. Los objetivos principales son: avanzar en el estudio de la influencia de algunas propiedades clave en el control del comportamiento de la WR en suelos quemados, así como estudiar la influencia de la cantidad y la calidad de la materia orgánica del suelo en su desarrollo cuando es afectada por el calentamiento. En éste estudio, hemos realizado quemas controladas en laboratorio utilizando muestras de suelo de diferentes sitios con litologías y tipos de suelos diferentes y recogidas bajo distintas especies vegetales. Las muestras recogidas en diferentes sitios difieren en algunas propiedades del suelo, mientras que las muestras de suelo tomadas del mismo sitio sólo se diferencian en la cantidad y la calidad de la materia orgánica del suelo, ya que se recogieron bajo distintas especies de plantas. Todas las muestras de suelo se calentaron en horno de mufla a 200, 250, 300 y 350 ºC. La repelencia al agua se midió mediante el test del tiempo de penetración de la gota de agua (WDPT). Los resultados mostraron diferencias significativas entre los tipos de suelos y especies vegetales, y se comprobó que pequeñas diferencias en algunas propiedades del suelo pueden actuar como factores clave controlando el desarrollo y persistencia de la repelencia al agua, con muestras de suelo quemadas que variaban entre hidrofílicas a extremadamente repelentes al agua. La propiedad que principalmente controló el comportamiento de la repelencia al calentamiento fue la textura y más concretamente el contenido de arena. Por otro lado se observó que la calidad de la materia orgánica también afecta, ya que muestras de suelo de mismo sitio y con contenido de materia orgánica similar, pero tomadas bajo diferentes especies vegetales mostraron valores muy diferentes de repelencia al agua tras la quema

Piezometric evolution in the aquifer of Aspe (Alicante)

El aprovechamiento de las aguas subterráneas de pequeños acuíferos ha jugado un papel fundamental en el desarrollo local, no siempre bien conocido y valorado. El acuífero de Aspe, en la provincia de Alicante, es un ejemplo en que este aprovechamiento ha estado relacionado históricamente con el crecimiento y desarrollo de la localidad de Aspe. La fuerte presión a la que se vio sometido durante buena parte del s. XX le llevó a una situación de sobreexplotación, de la cual apenas hay información. El abandono de muchas captaciones y la transformación del uso del territorio han permitido un cambio de su situación en las últimas décadas. El principal objetivo del presente trabajo ha sido actualizar el estado de conocimiento que se tiene de él y establecer su situación hidrodinámica. El seguimiento piezométrico ha permitido establecer una sectorización en función del comportamiento de los niveles piezométricos. Así, los sectores de las Fuentes y Tolomó han mostrado un ascenso progresivo, el cual no se corresponde con el comportamiento observado en los sectores de Alcaná y La Ofra. Estas diferencias de comportamiento apuntan a posibles desconexiones piezométricas entre sectores del acuífero.The use of groundwater in small aquifers has played a key role in local development, not always well known and valued. The aquifer of Aspe, in the province of Alicante, is an example in which this exploitation has been historically related to the growth and development of the town of Aspe. The strong pressure to which it was subjected during the twentieth century led to a situation of overexploitation, of which there is scarcely information. The abandonment of many wells and the transformation of land use have allowed a change of its situation in the last decades. The main objective of the present work has been to update the state of knowledge about it and establish its hydrodynamic situation. The piezometric monitoring has allowed to establish a sectorization according to the behaviors of the levels. Thus, the sectors of the Fuentes and Tolomó have shown a progressive piezometric level rise, which does not correspond to the behavior observed in the sectors of Alcaná and La Ofra. These differences in behavior point to possible piezometric disconnections between sectors of the aquifer.Este trabajo se ha realizado dentro del marco del proyecto ALTERACLIM (CGL2015-69773-C2-1) financiado por el Ministerio de Economía, Industria y Competitividad

Changes in soil microbial activity and physicochemical properties in agricultural soils in Eastern Spain

Agricultural land management greatly affects soil properties. Microbial soil communities are the most sensitive and rapid indicators of perturbations in land use and soil enzyme activities are sensitive biological indicators of the effects of soil management practices. Citrus orchards frequently have degraded soils and this paper evaluates how land management in citrus orchards can improve soil quality. A field experiment was performed in an orchard of orange trees (Citrus Sinensis) in the Alcoleja Experimental Station (Eastern Spain) with clay-loam agricultural soils to assess the long-term effects of herbicides with inorganic fertilizers (H), intensive ploughing and inorganic fertilizers (P) and organic farming (O) on the soil microbial properties, and to study the relationship between them. Nine soil samples were taken from each agricultural management plot. In all the samples physicochemical parameters, basal soil respiration, soil microbial biomass carbon, microbial indexes (BSR/C, Cmic/C and BSR/Cmic) and enzymatic activities (urease, dehydrogenase, ß-glucosidase and acid phosphatase) were determined. The results showed significant differences between the different agricultural management practices for the microbial properties and soil microbial indexes, since these were strongly associated with the soil organic matter content. Unlike herbicide use and intensive ploughing  - management practices that both showed similar microbial soil properties -  the organic management practices contributed to an increase in the soil biology quality, aggregate stability and organic matter content.As práticas de gestão agrícola afetam intensamente as propriedades do solo. As comunidades microbianas, são os indicadores mais rápidos e sensíveis face a perturbações no uso do solo enquanto as atividades enzimáticas funcionam como excelentes indicadores biológicos da qualidade do solo face aos efeitos dessas práticas de gestão. A cultura de citrinos é frequentemente responsável pela degradação dos solos, pelo que este estudo tem como objetivo avaliar como as práticas de gestão agrícola num pomar de citrinos podem contribuir para melhorar a qualidade do solo e as propriedades microbiológicas do mesmo. O ensaio foi realizado num pomar de laranjeiras (Citrus Sinensis) situado na Estação Experimental de Alcoleja (Valencia, Espanha), em solos agrícolas argilo-limosos, onde de instalaram três talhões submetidos a três práticas agrícolas distintas. O primeiro talhão (H) recebeu fertilização mineral e foram aplicados herbicidas; o segundo talhão (P) foi submetido a uma lavoura contínua e a fertilização mineral; e, por último, o talhão (O) foi submetido a agricultura de produção orgânica. De cada talhão foram colhidas nove amostras de solo, para determinação de: parámetros fisicoquímicos, respiração basal, carbono da biomassa microbiana, índices microbianos (BSR/C, Cmic/C y BSR/Cmic) e atividades enzimáticas (urease, deshidrogenase, ß-glucosidase e fosfatase ácida). Os resultados revelaram diferenças significativas entre os diferentes tipos de práticas agrícolas para os índices microbianos e propriedades microbiológicas, já que estes estão altamente relacionados com o teor de materia orgánica do solo. Por otro lado, os talhões H e P apresentaram resultados similares para as ditas propriedades, enquanto que o talhão com agricultura de produção orgânica apresentou os valores mais altos para o conteúdo em matéria orgánica, agregação e atividade biológica do solo.El manejo agrícola afecta a las propiedades del suelo así como a las comunidades microbianas, ya que son altamente sensibles frente a cambios en el uso del suelo y pueden utilizarse como indicadores de calidad frente a las perturbaciones en ese uso como, por ejemplo, las actividades enzimáticas. El cultivo del naranjo puede degradar los suelos, por lo que este estudio tiene como objetivo evaluar cómo el manejo agrícola en un cultivo de naranjo puede mejorar la calidad del suelo y las propiedades microbiológicas del mismo. El experimento se llevó a cabo en una finca de naranjos (Citrus Sinensis) situada en Alcoleja (comarca de la Costera, Valencia, España), donde se instalaron tres parcelas con tres manejos agrícolas distintos. La primera parcela (H) se encuentra fertilizada inorgánicamente y se aplican herbicidas; la segunda parcela (P) está sometida a un labrado continuo donde además se fertiliza inorgánicamente; y, por último, en la parcela (O) se aplica agricultura de producción ecológica. De cada parcela de estudio se tomaron nueve muestras de suelo, en las que se determinaron: parámetros fisicoquímicos, respiración edáfica basal, carbono de la biomasa microbiana, índices microbianos (BSR/C, Cmic/C y BSR/Cmic) y actividades enzimáticas (ureasa, deshidrogenasa, ß-glucosidasa y fosfatasa ácida). Los resultados mostraron diferencias significativas entre los distintos manejos agrícolas para los índices microbianos y las propiedades microbiológicas, ya que éstos están altamente relacionados con el contenido de materia orgánica del suelo. Por otro lado, las parcelas H y P obtuvieron resultados similares para dichas propiedades, mientras que la parcela con agricultura ecológica obtuvo los valores más altos para el contenido en materia orgánica, agregación y actividad biológica del suelo

The impact of crop diversification, tillage and fertilization type on soil total microbial, fungal and bacterial abundance: a worldwide meta-analysis of agricultural sites

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGMicroorganisms play a key role in nutrient cycling in agriculture and can contribute to improve soil quality and enhance crop production. Thus, there is a need to identify the most suitable management practices which foster increases in soil microbial biomass and diversity. A meta-analysis was performed to assess changes in microbial abundance in agricultural soils affected by: (i) management practices (tillage, fertilization and crop diversification); and (ii) environmental factors, including climate characteristics and soil properties. The scope of the meta-analysis was to evaluate whether microbial abundances are affected or not by organic fertilization or no fertilization, crop diversification (intercropping and crop rotations) and conservation tillage (reduced tillage/no-tillage) as an alternative to intensive conventional monocultures in agriculture. Only papers showing data on phospholipid fatty acids (PLFAs), providing indicators about soil microbial (total PLFA), fungal and bacterial biomass reached a critical mass to perform the meta-analysis. Therefore, soil microbial diversity could not be analyzed considering different management practices. Results showed that intercropping and crop rotations only significantly increased the abundance of fungi, with the corresponding increase in the fungal-to-bacterial ratio. Organic fertilization contributed to significant increases in bacterial and fungal abundance and total PLFA compared to mineral fertilization. Contrarily, the lack of fertilization negatively affected total PLFA, with no significant effect on bacterial and fungal abundances. Reduced tillage significantly increased total PLFA, fungal and bacterial abundances compared to conventional tillage, while no tillage had only a positive effect on fungi. Thus, as a general pattern, the adoption of sustainable management practices, mostly organic fertilization and reduced tillage, has overall positive effects on soil total microbial, fungal and bacterial abundance. These variables were not related to soil physicochemical properties and climatic factors, suggesting a positive global effect of sustainable management practices on soil microbial abundances. Thus, this study shows new insights by a meta-analysis of global studies about the effect of sustainable management practices on soil microbial abundances, needed for land-managers, policy-makers and farmers to select sustainable cropping systems that enhance microbial abundance.Ministerio de Economía y Competitividad | Ref. RYC-2015–18758Ministerio de Economía, Industria y Competitividad | Ref. RYC-2016–20411Ministerio de Ciencia e Innovación | Ref. FJC2019–039176-IXunta de Galicia | Ref. ED481D-2021/01

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

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