Assessing the sodium exchange capacity in rainfed and irrigated soils in the Mediterranean basin using GIS

El complejo de intercambio de suelo consiste en materiales coloidales en los que se producen fenómenos de intercambio iónico que le permiten atraer, retener e intercambiar elementos que tienen cargas eléctricas opuestas. Dado que sus constituyentes minerales (arcilla) y componentes orgánicos (humus) son principalmente de naturaleza negativa, los iones retenidos o intercambiados son predominantemente cationes. Históricamente, la falla en el monitoreo de parámetros como el porcentaje de intercambio de sodio (ESP) ha llevado al deterioro permanente de los suelos que se han vuelto completamente improductivos, reduciendo en gran medida la sostenibilidad de los sistemas agrícolas. Este estudio evalúa cómo la capacidad de intercambio de sodio en los suelos irrigados difiere de los de secano a través de una encuesta por muestreo que se llevó a cabo en las 15,031 ha del Perímetro de Riego de Caia y áreas adyacentes, ubicadas en los municipios de Elvas y Campo Maior, Distrito de Portalegre. Portugal, donde se recogieron 14,280 muestras georreferenciadas de la capa superior del suelo (0–20 cm), que se mezclaron 10 a la vez para que cada muestra compuesta represente 11.1 ha. Luego se analizaron las muestras con respecto a los parámetros más relevantes para caracterizar el complejo de intercambio de suelo, incluidas las concentraciones de bases intercambiadas y la Capacidad de intercambio de cationes (CEC). Los resultados se organizaron en una cuadrícula georreferenciada con 1451 entradas. Usando el software de análisis estadístico clásico y sistemas de información geográfica (GIS), fue posible relacionar las muestras individuales de suelo analizadas con el sistema cultural practicado (irrigado o de secano) y el grupo de suelo actual que nos permitió analizar la influencia del sistema cultural en El complejo de intercambio de suelo. Se creó la tabla de distribución del intercambio de sodio y CEC. Los resultados obtenidos confirman una disminución general de los valores de CEC y un aumento del contenido de sodio intercambiable de los suelos explorados irrigados en comparación con los de secano, presentando notables ideas no solo con respecto a los cambios necesarios hacia la sostenibilidad de estos paisajes agrícolas irrigados, sino también Considerando el impacto de estas técnicas productivas en diferentes sistemas agrícolas.The soil exchange complex consists of colloidal materials on which ion exchange phenomena occur allowing it to attract, retain, and exchange elements that have opposite electric charges. Since their mineral constituents (clay) and organic components (humus) are mainly of a negative nature retained or exchanged ion are predominantly cations. Historically, failing to monitor parameters like the exchange sodium percentage (ESP) has led to the permanent deterioration of soils which have become completely unproductive, largely reducing the sustainability of the agricultural systems. This study assesses how the sodium exchange capacity in irrigated soils differs from the rainfed ones through a sample survey that was carried out in the 15,031 ha of the Caia Irrigation Perimeter and adjacent areas, located in the municipalities of Elvas and Campo Maior, Portalegre District, Portugal where 14,280 georeferenced samples were collected from the top soil layer (0–20 cm), which were mixed 10 at a time so that each composite sample representing 11.1 ha. Then the samples were analyzed regarding the most relevant parameters for characterizing the soil exchange complex including the concentrations of exchanged bases and Cation Exchange Capacity (CEC). The results were arranged in a georeferenced grid with 1451 entries. Using classical statistical analysis and Geographic Information Systems (GIS) software, it was possible to relate the individual soil samples analyzed with the cultural system practiced (irrigated or rainfed) and the present soil group which permitted us to analyze the influence of the cultural system in the soil exchange complex. The distribution chart of the exchange sodium and CEC were created. The obtained results confirm a general decrease of CEC values and an increase of the exchangeable sodium content of irrigated explored soils when compared to the rainfed ones, putting forward noteworthy ideas not only regarding the necessary changes towards the sustainability of these irrigated agricultural landscapes, but also considering the impact of these productive techniques on different agricultural systems.• Fundação para a Ciência e a Tecnologia (Portugal). Proyecto UID / SOC / 04020/2013 • Universidad de Extremadura. Beca Postdoctroal GORSAS, para Luís Carlos LourespeerReviewe

Using GIS towards the characterization and soil mapping of the Caia irrigation perimeter

El perímetro de riego de Caia es una infraestructura de riego implementada en 1968. Como en otros casos, el mapa de los suelos originales de esta región (data de 1961) no tiene la precisión necesaria para caracterizar una zona de tamaño relativamente pequeño, donde tienen lugar unas prácticas agrícolas intensivas. Utilizando la metodología de la FAO y con el objetivo principal de establecer un mapa de suelo de mayor escala, adecuados a las exigencias de una agricultura intensiva y moderna, recolectamos la caracterización geológica de la zona de estudio y de información acerca de la topografía, el clima y la vegetación de la región. Utilizando el software ArcGIS, tenemos esta información superpuesta y establecemos un pre-mapa de los recursos del suelo. Sobre la base de esta pre-mapa, hemos definido un conjunto de itinerarios detallados en el campo, uniformemente distribuido, en la que se recolectaron muestras de suelo. En esas unidades de diferentes suelos, abrimos varios perfiles, a partir de los cuales hemos seleccionado 26 para analizar en el presente estudio. Estos caracterizan la diversidad existente en términos de tipo y propiedades de los suelos. Basado en el trabajo de verificación, corrección y la reinterpretación del anteproyecto de mapa de suelo, llegamos a un último mapa de suelo para el perímetro de riego de Caia, que se caracteriza por una enorme heterogeneidad, típico de los suelos mediterráneos, que contiene 23 unidades cartográficas distintas, siendo la más representativa la del Distrito Fluvisols con inclusiones del Distrito Luvisols, que ocupan el 29,9% del total del área de estudio, y calcisoles Luvic con inclusiones de Luvisols endoleptic con 11,9% del área total. Teniendo en cuenta la información obtenida sobre las propiedades del suelo, ArcGIS se utilizó para elaborar un mapa en el que era posible determinar el impacto de la práctica continua de riego en esta zona. Esto nos permite presentar las conclusiones pertinentes sobre la necesidad de monitorizar y tener acceso a los suelos mediterráneos específicos a fin de mitigar el impacto ambiental de las prácticas de riego.The Caia Irrigation Perimeter is an irrigation infrastructure implemented in 1968. As is often the case, the original soil map of this region (dated from 1961) does not have the detail needed to characterize a relatively small-sized zone, where intensive agricultural practices take place. Using FAO methodology and with the main goal of establishing a larger-scale soil map, adequate for the demands of a modern and intensive agriculture, we gathered the geological characterization of the study area and information about the topography, climate, and vegetation of the region. Using ArcGIS software, we overlapped this information and established a pre-map of soil resources. Based on this pre-map, we defined a set of detailed itineraries in the field, evenly distributed, in which soil samples were collected. In those distinct soil units, we opened several soil profiles, from which we selected 26 to analyze in the present study, since they characterized the existing diversity in terms of soil type and soil properties. Based on the work of verification, correction, and reinterpretation of the preliminary soil map, we reached a final soil map for the Caia Irrigation Perimeter, which is characterized by enormous heterogeneity, typical of Mediterranean soils, containing 23 distinct cartographic units, the most representative being the Distric Fluvisols with inclusions of Luvisols Distric occupying 29.9% of the total study area, and Calcisols Luvic with inclusions of Luvisols endoleptic with 11.9% of the total area. Considering the obtained information on soil properties; ArcGIS was used to develop a map in which it was possible to ascertain the impact of the continuous practice of irrigation in this area. This allows us to put forward relevant conclusions on the need to access and monitor specific Mediterranean soils in order to mitigate the environmental impact of irrigation practices.Trabajo patrocinado por: Centre for Spatial and Organizational Dynamics (CIEO) y . Ayuda económica Foundation for Science and Technology. Proyecto UID/SOC/04020/2013peerReviewe

Seasonal and interannual fluctuation of the microbial soil community in a maize field under long-term conservation agriculture management

Soil’s microbiological settlement in a Zea mays parcel under long-term agricultural practices aiming to minimize the disruption of the soil’s structure, composition and natural biodiversity was analyzed by culture-dependent and culture-independent processes. Of the different processes, morphological-type differentiation of cultured microflora produced the best results and, while Polymerase Chain Reaction (PCR)-agarose electrophoresis has also provided us with reliable ones, soil PCR-DGGE (Denaturing Gradient Gel Electrophoresis) did not, which may occur because of the dependence of the method on the practice. Over a three-year period, this soil seemed very stable as its C/N ratio remained roughly constant and available for microbial growth. Because no soil overturning occurred, we were able to maintain most of the cultured microbial population whose fluctuations depended only on edaphoclimatic conditions. The number of cultured bacteria, molds, total microorganisms, and the biodiversity indices were usually lower in the driest season (fall) than in the rest of the year, except for Acinetobacter and Stenotrophomonas, which showed the opposite behavior. Coincident with the rise in temperature during the summer, the relative abundance of Gram+ bacteria increased, mostly reflecting an increase in the spore-forming bacteria Streptomyces and Bacillus. Despite these variations, the evenness index and the quantity of distinct microbiological life remained practically unaltered, recovering their maximum levels when the proper edaphoclimatic conditions were present, which indicates the long-term stability of the microbial community in this soil. The performed study put forward important insights for assessing the sustainability of maize production under long-term conservation agriculture management systems, highlighting that adequate management might prevent the degradation of soil quality, thus contributing to promote sustainable agricultureinfo:eu-repo/semantics/publishedVersio

Combined use of olive mill waste compost and sprinkler irrigation to decrease the risk of As and Cd accumulation in rice grain

Sprinkler irrigation has been successfully introduced in rice production as an alternative to the traditional flooding system, allowing water savings and the reduction of As accumulation in the grain. However, the same conditions can increase Cd mobility and grain accumulation, an effect that needs to be countered. A 3-year field experiment was set-up in aMediterranean region (Extremadura, Spain), to evaluate howthe application of compost fromolivemillwaste (single application, 80 t ha−1), influences the accumulation of As and Cd in the grain under different irrigation regimes. Accumulation of As in the grain was always lower in the sprinkler irrigation when compared with the flooding irrigation, reaching a 5-fold difference in the third year. Compost application did not evidence a clear effect on the As accumulation in the rice grain, but highly significant negative correlations (p < 0.001) were obtained betweenAs content in the grain (total, inorganic, and organic) and the humification parameters in the soil, evidencing the importance of using a mature and stable organic amendment to avoid As accumulation in the grain. Cadmium accumulation in the rice grain decreased in each treatment where compost was applied, relatively to the non-treated counterpart (e.g., from 0.080 to <0.010 mg kg−1, in direct seeding with sprinkler irrigation, in the third year). There were no significant differences in the total inorganic As between treatments with or without compost application, but it was possible to observe an increase in the predominance of the organic As over themore toxic inorganic As,when compost was applied, allowing a decrease in the risk associated to As accumulation. Therefore, the aerobic cultivation of rice, with the simultaneous application of an adequate source of organic matter, can be considered a good solution to cope with the risk of accumulation of As and Cd in the rice graininfo:eu-repo/semantics/publishedVersio

Encontro Anual das Ciências do Solo de 2021: Desafios da gestão do solo num contexto de alterações climáticas

Nota introdutória O papel do solo no ciclo do carbono tem ganho crescente relevância no atual contexto de alterações climáticas. Globalmente, o solo armazena mais carbono do que a atmosfera e a biomassa terreste. A gestão do solo pode determinar a sua ação como sumidouro ou como emissor de gases com efeito de estufa. Os solos agrícolas e pastagens em Portugal têm registado uma diminuição das emissões de gases com efeito de estufa ao longo nas últimas décadas. Torna-se necessário continuar e ampliar este efeito e transformar o solo num sumidouro de carbono, sendo esta função do solo esperada e necessária para atingir a planeada neutralidade carbónica em 2050. Se o aumento de matéria orgânica dos solos agrícolas em Portugal se evidencia cada vez mais como fundamental em termos de regulação do clima, este tem vindo a ser um desafio de gestão de longa data. No entanto, os solos em Portugal continuam a apresentar valores médios de matéria orgânica baixos, situação que se tende a acentuar com o processo de desertificação. Numa época em que o regadio tem sofrido forte impulso, quer como forma de suprir as necessidades alimentares de uma população mundial em permanente crescimento, quer como forma de resposta às alterações climáticas que colocam o Sul da Europa como uma região em elevado risco de desertificação, convém analisar os impactos edáficos desta prática, nomeadamente no que respeita ao teor de matéria orgânica bem como no que respeita aos riscos de salinização e de outras formas de degradação do solo. Propõe-se o EACS 2021 como um fórum privilegiado de apresentação e discussão de formas de gestão integradas do solo e água em sistemas agrícolas, florestais e agroflorestais que contribuam para prevenir a degradação do solo, diminuir os impactos das alterações climáticas e assegurar a sustentabilidade dos sistemas

Encontro Anual das Ciências do Solo de 2021 : desafios da gestão do solo num contexto de alterações climáticas : livro de resumos.

O papel do solo no ciclo do carbono tem ganho crescente relevância no atual contexto de alterações climáticas. Globalmente, o solo armazena mais carbono do que a atmosfera e a biomassa terreste. A gestão do solo pode determinar a sua ação como sumidouro ou como emissor de gases com efeito de estufa. Os solos agrícolas e pastagens em Portugal têm registado uma diminuição das emissões de gases com efeito de estufa ao longo nas últimas décadas. Torna-se necessário continuar e ampliar este efeito e transformar o solo num sumidouro de carbono, sendo esta função do solo esperada e necessária para atingir a planeada neutralidade carbónica em 2050. Se o aumento de matéria orgânica dos solos agrícolas em Portugal se evidencia cada vez mais como fundamental em termos de regulação do clima, este tem vindo a ser um desafio de gestão de longa data. No entanto, os solos em Portugal continuam a apresentar valores médios de matéria orgânica baixos, situação que se tende a acentuar com o processo de desertificação. Numa época em que o regadio tem sofrido forte impulso, quer como forma de suprir as necessidades alimentares de uma população mundial em permanente crescimento, quer como forma de resposta às alterações climáticas que colocam o Sul da Europa como uma região em elevado risco de desertificação, convém analisar os impactos edáficos desta prática, nomeadamente no que respeita ao teor de matéria orgânica bem como no que respeita aos riscos de salinização e de outras formas de degradação do solo. Propõe-se o EACS 2021 como um fórum privilegiado de apresentação e discussão de formas de gestão integradas do solo e água em sistemas agrícolas, florestais e agroflorestais que contribuam para prevenir a degradação do solo, diminuir os impactos das alterações climáticas e assegurar a sustentabilidade dos sistemas.info:eu-repo/semantics/publishedVersio

Combined use of biochar and sprinkler irrigation may enhance rice productivity in water-stressed regions

A 2-year field experiment was conducted to analyse the effects of fresh and aged biochar on soil properties, as well as herbicide effectiveness and rice-yield components in a Mediterranean environment. Six managements were used: no-tillage and sprinkler irrigation either without (NoT) or with first-year biochar application (NoTB), conventional tillage and sprinkler irrigation either without (ConvT) or with first-year biochar application (ConvTB), conventional tillage and flooding irrigation either without (ConvTF) or with first-year biochar application (ConvTFB). The measurements done in the first (2018) and second (2019) years after biochar addition were taken to determine its fresh and aged effects, respectively. The application of biochar led to an improvement of the soil properties such as increase in the soil's organic carbon content, pH, and dehydrogenase activity. It also reduced weed pressure, regardless of the management used, and sprinkler systems were found to have the greatest herbicide effectiveness, especially in ConvT and ConvTB. In terms of production, there were significant increases in yield with the application of fresh biochar, in the amended managements under tillage compared with their unamended counterparts. The greatest yields were found under ConvT and ConvTB, with mean values for both treatments of 10,770 and 11,299 kg ha−1 in the fresh and aged years, respectively. Furthermore, water productivity reached its greatest values when sprinkler was used, especially with tillage for which the application of fresh biochar increased water productivity by a factor of 1.09 relative to ConvT. Therefore, sprinkler irrigation in combination with tillage and biochar applications can be regarded as an efficient alternative to flooding irrigation in order to ensure productive viability of rice in water-stressed regions