Plant diversity drives soil microbial biomass carbon in grasslands irrespective of global environmental change factors

Soil microbial biomass is a key determinant of carbon dynamics in the soil. Several studies have shown that soil microbial biomass significantly increases with plant species diversity, but it remains unclear whether plant species diversity can also stabilize soil microbial biomass in a changing environment. This question is particularly relevant as many global environmental change (GEC) factors, such as drought and nutrient enrichment, have been shown to reduce soil microbial biomass. Experiments with orthogonal manipulations of plant diversity and GEC factors can provide insights whether plant diversity can attenuate such detrimental effects on soil microbial biomass. Here, we present the analysis of 12 different studies with 14 unique orthogonal plant diversity × GEC manipulations in grasslands, where plant diversity and at least one GEC factor (elevated CO2, nutrient enrichment, drought, earthworm presence, or warming) were manipulated. Our results show that higher plant diversity significantly enhances soil microbial biomass with the strongest effects in long-term field experiments. In contrast, GEC factors had inconsistent effects with only drought having a significant negative effect. Importantly, we report consistent non-significant effects for all 14 interactions between plant diversity and GEC factors, which indicates a limited potential of plant diversity to attenuate the effects of GEC factors on soil microbial biomass. We highlight that plant diversity is a major determinant of soil microbial biomass in experimental grasslands that can influence soil carbon dynamics irrespective of GEC.

(Table 1) Cation exchange capacity and other characteristics of soils common in Lower Saxony, Germany

The chemical and biochemical processes associated with the filtration of rainwater through soils, a step in groundwater recharge, were investigated. Under simulated climatic conditions in the laboratory, undisturbed soil columns of partly loamy sands, sandy soils and loess were run as lysimeters. A series of extraction procedures was carried out to determine solid matter in unaltered rock materials and in soil horizons. Drainage water and moisture movement in the columns were analysed and traced respectively. The behaviour of soluble humic substance was investigated by percolation and suspension experiments. The development of seepage-water in the unsaturated zone is closely associated with the soil genetic processes. Determining autonomous chemical and physical parameters are mineral composition and grain size distribution in the original unconsolidated host rock and prevailing climatic conditions. They influence biological activity and transport of solids, dissolved matter and gases in the unsaturated zone. Humic substances, either as amorphous solid matter or as soluble humic acids play a part in diverse sorption, solution and precipitation processes.

Implementación de la producción de lombricultura

El presente estudio reflejará cómo es llevada a cabo la lombricultura, la misma es conocida como una actividad centrada en la crianza de lombrices, en este caso se utiliza la lombriz roja californiana, dicho animal es el responsable de la producción de humus, el cual se obtiene por medio de un proceso de transformación, que está ligado íntimamente al reciclado de basura y la excreción de humus. Es necesario resaltar que tal actividad permite perfeccionar todos los sistema s de producción agrícola, ya que brinda nutrientes al suelo, muchas veces deteriorado por la erosión continua producida por ciertas explotaciones agrícolas, el uso de fertilizantes químicos, y demás factores que degradan la tierra, el producto responsable de esta beneficiosa tarea es el humus, el cual es un fertilizante de primer orden, calidad y de muy bajo costo. Este estudio se lleva a cabo en la empresa Fenix S.A. quien aporta su espacio para la lombricultura. El proyecto se realiza con el fin de poder reducir el uso de fertilizantes químicos por el abono orgánico conocido como humus, permitiendo a su vez, mejorar la calidad del suelo, recibir y aplicar nuevos conocimientos y metodologías en función de buenas practicas agrícolas, además esto les permite ser los productores de su propio abono, lo que implica una gran reducción en sus costos.

Héroe y gente en el resurgimiento italiano : el caso Garibaldi

Desde 1861 hasta hoy, aunque con interpretaciones muy diferentes, Garibaldi es un ícono de la historia italiana y ha sido y es la opción ideal del héroe que luchó por la unificación de Italia, por la libertad de los otros pueblos, al representar siempre un modelo de personaje funcional en perspectiva pedagógica para la dimensión unitaria del país. Se desencadenó así un proceso sociológico de identificación a través de las imágenes y un registro de la memoria que ha encontrado su desarrollo en la epopeya garibaldina de la Primera Guerra Mundial y más tarde en la epopeya de la Resistencia. La leyenda garibaldina se transmitió, además, a través de la literatura, gracias a escritores como Edmundo de Amicis, a través del cual se puede apreciar el elogio del patrimonio cultural que representan los grandes escritores del pasado, como humus de la alcanzada unidad del país. Después de su muerte, la iconografía monumental intentará enviar un mensaje de unidad política de los italianos, erigiendo estatuas en las que se representan a Garibaldi y a Vittorio Emanuele, ambos a caballo, con la idea simbólica de un encuentro entre la revolución democrática de uno y el centralismo monárquico del otro.

Comportamiento del Chile Húngaro (Capsicum annuum) en mezclas de vermicompost- arena bajo condiciones protegidas

El trabajo se realizó para determinar la concentración óptima de la mezcla vermicompost:arena (VC:A; v:v) que satisfaga las necesidades nutricionales del cultivo de chile tipo Húngaro (Capsicum annum) bajo condiciones protegidas. Las mezclas evaluadas fueron cuatro combinaciones de VC:A con las relaciones 1:1, 2:1, 3:1, 4:1 y un testigo 0:1 (arena más solución nutritiva). Las variables evaluadas fueron altura de planta y diámetro basal del tallo, en el fruto longitud, diámetro ecuatorial, espesor del pericarpio, número de lóculos, peso y rendimiento. Se utilizó un diseño en bloques al azar con cinco repeticiones. Para determinar el efecto de los tratamientos sobre las variables evaluadas se aplicó el ANDEVA y para la comparación de medias se utilizó la prueba de Tukey0,05. Se determinó que para las variables evaluadas en el cultivo del chile como: altura de planta, diámetro basal del tallo, longitud del fruto, espesor del pericarpio, número de frutos por planta, peso de fruto y rendimiento, presentaron diferencias altamente significativas (P≤0,01) mientras que las variables diámetro ecuatorial y número de lóculos del fruto resultaron estadísticamente iguales. La relación 1:1 en volumen de VC:A resultó la mezcla más adecuada para el desarrollo del cultivo de chile tipo Húngaro bajo condiciones protegidas.

Pollen record from Golkow, Poland

Janczyk-Kopikowa (1966): The series of the organic deposits, developed in the vicinity of Golkow near Warsaw as oil shales and peats, was laid down in a grough valley and now rests on the deposits of the Middle Polish Glaciation (Riss). The organic deposits are overlain by the fluviale deposits of the North Polish Glaciation (Würm). The locality Golkow occurs beyond the extent of the continental glacier of this glaciation. Polen analysis completed by microfloristic examinations allows to determine the age of the organic series that is thought to be Eemian. The pollen diagram from Golkow does not call in question the stratigraphical position of the deposits investigated mainly due to its characteristic features such as minimum content of coniferous trees in the climatic optimum - about 5%, high percentage of Corylus - 77.5% and well developed phase of hornbeam. It may be well compared with other Eemian diagrams from the area of Poland and reveals much similar features. The development of vegetation at Golkow has depended upon the prevailing climate. At first, the cool climate brings about the development of plants having small thermal requirements. Here belong thin, park-like forests with pine and birch (Pinus, Betula) accompanied by the heliophilic plants such as Hippohäe and Ephedra. Improvement of climate that becomes warm and humid provides for development of deciduous forests prevailing in the climatic optimum, of the interglacial. Decrease of temperature causes a repeated change in the type of forest. This latter changes into coniferous forest with prevailing spruce (Picea) and fir (Abies) at the beginning, and then with pine (Pinus) and birch (Betula). During the Eemian Interglacial, the development of plants at Golkow terminates with a new and long-lasting predominance of pine-birch forests. However, such a longevity may be apparent only. Apparent character of this phenomenon is proved by a fact that the pollen spectra of the warm climatic periods have found their reflex in the oil shale that increased considerably slower than the layers off feebly decomposed peat evidencing the existence of cool pine-birch forests from the decline of the Interglacial. The water basin, in which the polen grains were laid down from surrounding plants is characterized by a calm sedimentation as proved by the occurrence of the oil shale. An insignificant water flow left behind some thin sand laminae. The not too deep basin becomes shallower owing to the growing water vegetation, and marshy vegetation. The growing of the plants causes a complete shallowing of the basin and formation of peat bog in situ, as proved by the peat beds occurring in the section. ---- Gadomska (1966): In the vicinity of Golków a series of organic deposits occurs amounting to 6.5-9.3 m in thickness, and consisting of oil shales, lacustrine silts and sands, as well as peats and peaty silts. The organic deposits fill up an old, small, but fairly deep lake basin, probably of finger-lake origin. It may be seen to-day as a slight lowering of the relief, filled up with soaked ground, stretching from north to south. On the basis of palaeobotanical examinations the organic deposits considered are of Eemian Interglacial age (Z. Janczyk-Kopikowa, 1063). The lower part of the organic series consists of a compact oil shale horizon, the maximum thickness of which may attain up to 8 m. The oil shales contain particularly in their upper part, numerous intercalations of arenaceous silts, dark grey or black in colour, or of sands mainly of lacustrine provenance. At the top of the oil shales are found peats, up to 2.5 m in thickness, covered by black, humus silts with numerous plant remains. The Eemian Interglacial deposits are covered by a series of fluviatile sands belonging partly to the Baltic Glaciation (bottom part of the series), partly to the Holocene (top part of the series). The thickness of the sands is 0.5-3.7 m. Higher up, there are found the Holocene and present-day deposits developed as clayey alluvion, or arenaceous slide rocks, or arenaceous-silty soil.

Vegetation in the coastal area of East Greenland

This paper deals with the syntaxonomy and ecology of debris, scree and alluvium vegetation of the Ammassalik district, Southeast Greenland, on more or less moist soil. The Oxyria digyna- and Chamaenerion latifoliumvegetation types are classified as Saxifrago-Oxyrietum digynae (Böcher 1933 ap. Nordh. 1943) Gjaerevoll 1950 respectively Chamaenerietum latifolii Böcher 1933 in the class Thlaspietea rotundifolii Br.-BI. ap. Br.-BI. et al. 1947. The chionophytic Saxifrago-Oxyrietum digynae and the Chamaenerietum latifolii occurring on river-banks are classified in the alliance Saxifrago stellaris-Oxyrion digynae Gjaerevoll 1950. This alliance belongs to the order Androsacetalia alpinae Br.-BI. ap. Br.-BI. & Jenny 1926, Thlaspietea rotundifolii Br.-BI. ap. Br.-BI. et al. 1947. The following syntaxa are described as new: Saxifrago-Oxyrietum digynae stellarietosum humifusae and typicum with two variants and one variant of the subassociation inops De Molenaar 1976, and the Chamaenerietum latifolii typicum with two variants and salicetosum herbaceae with three variants.

La influencia argentina en la configuración de la historiografía uruguaya. Estudio de caso: Francisco Bauzá

En la segunda mitad del siglo XIX se crearon en el Río de la Plata las condiciones necesarias para el surgimiento y desarrollo de las historiografías nacionales, humus primordial del cual emergieron proposiciones fácticas y axiomas historiográficos de cuño patriótico. La historiografía argentina, por diversidad de motivos -disponibilidad de insumos heurísticos y repertorios bibliográficos, número de intelectuales (historiadores, poetas, novelistas, ensayistas) consagrados al estudio y exaltación del pasado nacional, instituciones dedicadas al desarrollo de la investigación, recursos aportados por el Estado- tuvo un temprano e importante desarrollo e influyó de forma determinante en la historiografía uruguaya. El objeto de este artículo es conocer las modalidades, el carácter y significación de esta influencia en un autor concreto, Francisco Bauzá, a efectos de dilucidar los cimientos sobre los cuales se definieron las estructuras teóricas y la preceptivas técnico-metodológicas fundantes de la disciplina en Uruguay.

Predicting changes in abundance and juvenile proportions of earthworms in the field using glmmADMB in R

The study aimed at investigating effects of three differently acting biocides; the insecticide esfenvalerate, the fungicide picoxystrobin and the bactericide triclosan, applied individually and as a mixture, on an earthworm community in the field. A concentration-response design was chosen and results were analyzed using univariate and multivariate approaches. Effects on juvenile proportions were less pronounced and more variable than effects on abundance, but effects in general were species- and chemical-specific, and temporal variations distinct. Esfenvalerate and picoxystrobin appeared to elicit stronger effects than triclosan at laboratory-based ECx values, which is in accordance with our previous laboratory study on Eisenia fetida. The mixture affected abundance and juvenile proportions, but the latter only at high mixture concentrations. Esfenvalerate and picoxystrobin appeared to be the main drivers for the mixture's toxicity. Species-specific toxicity patterns question the reliability of mixture toxicity predictions derived on E. fetida for field earthworms. Biocide concentrations equaling EC50s (reproduction) for E. fetida provoked effects on the field earthworms mainly exceeding 50%, indicating effect intensification from the laboratory to field as well as the influence of indirect effects produced by species interactions. The differing results of the present field study and the previous laboratory study imply that lower- and higher-tier studies may not be mutually exclusive, but to be used in complementary.

La influencia argentina en la configuración de la historiografía uruguaya. Estudio de caso: Francisco Bauzá

En la segunda mitad del siglo XIX se crearon en el Río de la Plata las condiciones necesarias para el surgimiento y desarrollo de las historiografías nacionales, humus primordial del cual emergieron proposiciones fácticas y axiomas historiográficos de cuño patriótico. La historiografía argentina, por diversidad de motivos -disponibilidad de insumos heurísticos y repertorios bibliográficos, número de intelectuales (historiadores, poetas, novelistas, ensayistas) consagrados al estudio y exaltación del pasado nacional, instituciones dedicadas al desarrollo de la investigación, recursos aportados por el Estado- tuvo un temprano e importante desarrollo e influyó de forma determinante en la historiografía uruguaya. El objeto de este artículo es conocer las modalidades, el carácter y significación de esta influencia en un autor concreto, Francisco Bauzá, a efectos de dilucidar los cimientos sobre los cuales se definieron las estructuras teóricas y la preceptivas técnico-metodológicas fundantes de la disciplina en Uruguay.

La influencia argentina en la configuración de la historiografía uruguaya. Estudio de caso: Francisco Bauzá

En la segunda mitad del siglo XIX se crearon en el Río de la Plata las condiciones necesarias para el surgimiento y desarrollo de las historiografías nacionales, humus primordial del cual emergieron proposiciones fácticas y axiomas historiográficos de cuño patriótico. La historiografía argentina, por diversidad de motivos -disponibilidad de insumos heurísticos y repertorios bibliográficos, número de intelectuales (historiadores, poetas, novelistas, ensayistas) consagrados al estudio y exaltación del pasado nacional, instituciones dedicadas al desarrollo de la investigación, recursos aportados por el Estado- tuvo un temprano e importante desarrollo e influyó de forma determinante en la historiografía uruguaya. El objeto de este artículo es conocer las modalidades, el carácter y significación de esta influencia en un autor concreto, Francisco Bauzá, a efectos de dilucidar los cimientos sobre los cuales se definieron las estructuras teóricas y la preceptivas técnico-metodológicas fundantes de la disciplina en Uruguay.

Documentation, profile descriptions and analytical results of loes profiles from Bavaria, southern Germany

This study investigates the landscape evolution and soil development in the loess area near Regensburg between approximately 6000-2000 yr BP (radiocarbon years), Eastern Bavaria. The focus is on the question how man and climate influenced landscape evolution and what their relative significance was. The theoretical background concerning the factors that controlled prehistoric soil erosion in Middle Europe is summarized with respect to rainfall intensity and distribution, pedogenesis, Pleistocene relief, and prehistoric farming. Colluvial deposits , flood loams, and soils were studied at ten different and representative sites that served as archives of their respective palaeoenvironments. Geomorphological, sedimentological, and pedological methods were applied. According to the findings presented here, there was a high asynchronity of landscape evolution in the investigation area, which was due to prehistoric land-use patterns. Prehistoric land use and settlement caused highly difIerenciated phases of morphodynamic activity and stability in time and space. These are documented at the single catenas ofeach site. In general, Pleistocene relief was substantially lowered. At the same time smaller landforms such as dells and minor asymmetric valleys filled up and strongly transformed. However, there were short phases at many sites, forming short lived linear erosion features ('Runsen'), resulting from exceptional rainfalls. These forms are results of single events without showing regional trends. Generally, the onset of the sedimentation of colluvial deposits took place much earlier (usually 3500 yr BP (radiocarbon) and younger) than the formation of flood loams. Thus, the deposition of flood loams in the Kleine Laaber river valley started mainly as a consequence of iron age farming only at around 2500 yr BP (radiocarbon). A cascade system explains the different ages of colluvial deposits and flood loams: as a result of prehistoric land use, dells and other minor Pleistocene landforms were filled with colluvial sediments. After the filling of these primary sediment traps , eroded material was transported into flood plains, thus forming flood loams. But at the moment we cannot quantify the extent ofprehistoric soil erosion in the investigation area. The three factors that controlled the prehistoric Iandscapc evolution in the Ioess area near Regensburg are as follows: 1. The transformation from a natural to a prehistoric cultural landscape was the most important factor: A landscape with stable relief was changed into a highly morphodynamic one with soil erosion as the dominant process of this change. 2. The sediment traps of the pre-anthropogenic relief determined where the material originated from soil erosion was deposited: either sedimentation took place on the slopes or the filled sediment traps of the slopes rendered flood loam formation possible. Climatic influence of any importance can only be documented as the result of land use in connection with singular and/or statistic events of heavy rainfalls. Without human impact, no significant change in the Holocene landscape would have been possible.