Soil microbiological properties and its stratification ratios for soil quality assessment under different cover crop management systems in a semiarid vineyard

In vineyards in Spain, tillage and semiarid Mediterranean climatic conditions accelerate organic matter loss from the soil. Cover crops are a conservation management practice that can provoke changes in soil quality which requires evaluation. Stratification ratios of soil properties such as soil organic C and labile C fractions have been proposed for the assessment of soil quality under different soil management systems. Our objective was to study the effect of different cover crop management on various soil parameters and their stratification ratios. We evaluated three different soil managements in a Typic Haploxerept from NE Spain: conventional tillage (CT); 5‐y continuous cover crop of resident vegetation (RV); and 4‐y continuous cover crop of Festuca longifolia Thuill., followed by 1‐y Bromus catharticus L. after resowing (BV). We monitored soil organic C, particulate organic C, water soluble C, potentially mineralizable N, microbial biomass C, β‐glucosidase and urease enzymatic activities, and water stable aggregates at 0–2.5, 2.5–5, 5–15, 15–25, and 25–45 cm soil depths. We calculated soil depth stratification ratios of those soil properties. Resident cover crop increased microbiological properties, labile C fractions, and aggregation with respect to conventional tillage at 0–2.5 and 2.5–5 cm soil depths. However, for Bromus cover crop the same soil properties were lower than for the resident cover crop at 0–2.5 cm depth. Stratification ratios of β‐glucosidase and urease enzymatic activities, and particulate organic C showed a higher sensitivity than other soil properties; therefore, they would be the best indicators for soil quality assessment in semiarid Mediterranean vineyards.     

Rehabilitation of Nothofagus pumilio forests in Chilean Patagonia: can fencing and planting season effectively protect against exotic European hare browsing?

New Forests - In forests affected by heavy fires and continuous grazing of exotic herbivorous mammal species, Nothofagus pumilio (lenga) cannot recover naturally. The main factors that hinder the...     

Einfaches Dünnschichtchromato-Graphisches Verfahren zur Bestimmung von Ergosterin und Vitamin D nebeneinander in Futterhefeerzeugnissen

Zusammenfassung Es wurde eine Schnellmethode zur Bestimmung von Ergosterin und Vitamin D in Futterhefe-Suspension und in getrockneter Futterhefe ausgearbeitet. Beide Wirkstoffe werden mit Äther extrahiert. Ein Teil der im Hefeextrakt vorhandenen störenden Stoffe wird durch Verseifung entfernt. Der unverseifbare Rückstand wird in Chloroformlösung auf Kieselgel G Schicht aufgetragen. Nach Chromatographieren im Cyclohexan-Äther Gemisch (1 : 1) und Besprühen mit Ammonium-Trichloridlösung werden die Ergosterin-und Vitamin- D-Flecken voneinander und von den störenden Stoffen scharf getrennt sichtbar. Die Menge der zu bestimmende Stoffe wird durch Vergleich mit den aus gleichzeitig chromatographierten, bekannte Ergosterin- und Vitamin-D-Mengen enthaltenden Lösungen gebildeten Flecken festgestellt. Der mittlere Fehler der Methode beträgt für beide Wirkstoffe 8,3%.

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Summary A rapid method has been evolved for the determination of ergosterol and vitamin D in feed yeast milk and dry feed yeast.Ergosterol and vitamin D have been extracted by diethyl ether.Part of the haze materials that are found in the yeast extract is isolated by saponification. The chloroform solution of the unsaponifiable residue is plated on a layer of kieselgel G.After plating in a mixture of cyclohexane and ether, in a ratio of 1 to 1, and after developing with a solution of antimony trichloride, the spot of ergosterol and that of vitamin D are distinctly separated from each other and from that of the haze materials.The quantitative determination of each is obtained by comparison with spots containing known quantities of ergosterol and vitamin D that are being plated at the same time.The mean error of this method is 8.3% for each of these substances.

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Résumé Une méthode rapide était élaborée pour le dosage d'ergostérol et vitamine D dans le lait de levure fourragère et dans la levure fourragère sèche.L'ergosterol et la vitamine D ont été extraites par lyse à l'éther di-éthylique.Une partie des matériaux troubles qui se trouve dans l'extrait de levure est isolée par saponification. La solution chloroformique du reste nonsaponifiable est portée sur la couche de Kieselgel G.Après l'introduction dans un mélange de cyclohéxane et d'éther dans la proportion de 1 à 1 et après de développement avec la solution du trichlorure, d'antimoine, la tache de l'ergosterol et celle de la vitamine D s'isolent nettement l'une de l'autre et des matériaux troubles.Le dosage de la quantité de celles-ci se produit chacun isolément à l'aide de la comparaison avec les taches contenant des quantités connues d'ergosterol et de vitamine D qui sont séparés simultanément.L'erreur moyenne de la méthode est de 8,3% chez chacun des deux substances.

     

Studies on the Persistence of a Commercial Formulation of Chlorpyrifos on an Agricultural Soil from Provincia de Buenos Aires,República Argentina

Mercury and cadmium are priority hazardous substances. Some titanosilicates have been tested for the removal of Cd²⁺ and Hg²⁺ from single solutions by ion exchange. In this work, the competition between both contaminants for the exchanger binding sites of titanosilicate Engelhard titanosilicate material number 4 (ETS-4) was studied by performing batch experiments with aqueous solutions containing the two counter ions. The results evidenced the large capacity of ETS-4 and shown that the cadmium(II) diffusivity through the sorbent is higher than that of mercury(II). Furthermore, the ETS-4 exhibited higher kinetic and equilibrium selectivities for Cd²⁺, which attained values in the ranges 8.9–12.5 and 7.9–12.8, respectively. With respect to modelling, the pseudo-second-order equation described successfully the competitive removal of Cd²⁺ and Hg²⁺.     

Arbuscular mycorrhizal root colonization and soil P availability are positively related to agrodiversity in Mexican maize polycultures

In Los Tuxtlas, Mexico, the local Popoluca people maintain the traditional management of their maize agroecosystems. However, it is not known whether the loss of agrodiversity over recent decades has affected mycorrhizal populations, nutrient availability, and crop productivity. This study utilized linear mixed effect models to analyze the relationship between agrodiversity (three, six, and greater than or equal to eight cultivated species) and (a) arbuscular mycorrhizal fungi (AMF) inoculum potential, measured as the most probable number (MPN) of propagules and colonization level, (b) nutrient availability, and (c) aboveground maize productivity. We also investigated the relationship between soil nutrient content and inoculum potential. Soil samples were taken before planting, and during flowering, in the 2009 maize cycle. We found that AMF colonization level of maize roots and P availability increased with planted species richness, but that this effect only occurred at the flowering sampling date. Plots with a higher MPN of propagules presented increased C and NO ₃ ^? contents and lower C/N ratio than those with lower MPN of propagules, regardless of agrodiversity. Soils that produced the highest maize root colonization level also featured high P availability and N content. We conclude that decreased agrodiversity in these traditional systems does not significantly affect the soil MPN of propagules, but may have a negative impact on the ability of the mycorrhizal community to colonize maize roots, as well as reducing the availability of P, which is often the most limiting nutrient in tropical soils.     

Perceptions of fishers to sea turtle bycatch,illegal capture and consumption in the San Ignacio‐Navachiste‐Macapule lagoon complex,Gulf of California,Mexico

In this study, 10% of all registered fishermen in the coastal towns of Navachiste in Sinaloa, in northwestern Mexico, answered a survey designed to collect data on their perceptions of the following topics: the impact of turtle meat consumption; human health; bycatch; illegal turtle fishing; the illegal sea turtle market; the local economy; pollution; environmental education; the success of protective legislation; and sea turtle‐based ecotourism. Perceptions were analyzed using the fuzzy logic method through classification into 5 fuzzy membership sets: VL, very low; L, low; M, moderate; H, high; VH, very high. The 9 topics generated decision areas upon applying fuzzy inference that revealed the membership level of the answers in each fuzzy set. The economic potential of sea turtle‐based ecotourism and the economic profitability of the illegal turtle meat market were perceived as VL. Conservation legislation was perceived as H, although inefficiently applied due to corruption. Ecotourism and impacts on sea turtles were perceived as VL, because they were deemed unprofitable activities at the individual and community levels. Environmental education was perceived as L, because it centers on nesting, hatching and releasing turtles and is directed at elementary and middle‐school students. While fishers perceive a serious negative impact of fishing activities on sea turtles in the San Ignacio‐Navachiste‐Macapule area, they do not see themselves individually as part of the problem. Achieving sea turtle conservation in this region requires: suitable ecotourism infrastructure, government investments in promotion, and studies to estimate the minimum number of tourists needed to assure profitability.     

Ground vegetation as an indicator of site quality: effect of non-site factors on the productivity of newly established chestnut plantations in northwestern Spain

The growth of 67 young hybrid (Castanea × coudercii A. Camus) and pure sweet chestnut (Castanea sativa Mill.) plantations was studied in relation to ground vegetation (GV) and non-site factors such as type of site preparation, weed control (WC), disease-related damage and prior land use. The classification and regression trees procedure was used to analyse the data. Ground vegetation communities accounted for a large amount of variability in the site index (SI) and were found to be useful as predictors of chestnut site quality. The presence of broom communities indicated the best site for establishing chestnut plantations, whereas bracken and bramble communities indicated poorer conditions, although those sites can still be considered suitable for growing chestnut. Terrain covered with herbaceous communities also indicated intermediate or even good site conditions. The poorest sites were the heathlands. As regards non-site factors, only weed control was found to be a significant variable. Ground vegetation caused a significant reduction in tree growth, indicating the importance of carrying out regular weeding to improve productivity. The most positive effect of weeding on height growth was detected in terrain covered by gorse and broom, and the least positive effect was observed in heathland. The findings are important for forest management purposes, as evaluation of ground vegetation will enable rapid prediction of site productivity classes in afforested areas and help in selecting the best land for planting this species in reforestation programmes.     

Species selection for reforestations: what happens with historic local extinctions and habitat protection zones? A case study in the Cantabrian Range

Species selection for reforestations can be challenging in habitat protection zones, especially in human transformed landscapes, where nativeness of some species is not easily determined and yet is crucial for knowing whether a species can be used or not. We try to determine whether Pinus uncinata Ramond ex DC was present in the Cantabrian Range (Spain) and whether it could have disappeared recently due to anthropogenic causes. Plant morphology and needle anatomy were characterized in Pinus sylvestris L. and P. uncinata 2-year-old seedlings. An analysis of variance was used for selecting morphological markers capable of discriminating both species. These markers permit the comparison of seedlings coming from the highest zone of Puebla de Lillo relict pinewood (Cantabrian Range) with reference material from Castillo de Vinuesa (Iberian Range). This comparison was firstly made with two multivariate methods, a principal component analysis and a multivariate discriminant analysis. Subsequently, this was corroborated with the detection of a species-specific chloroplast DNA marker. The differences found between both species reflect the better adaptation of P. uncinata to typical highland environment. Several Puebla de Lillo seedlings had P. uncinata type morphology and haplotype, suggesting the presence of this species in the Cantabrian Range until recently. This discovery changes the current interpretation of the zone’s vegetation, enhancing the natural presence of highland open pinewoods. However, human activities (fire and livestock grazing) have driven them to extinction and have favoured the contemporary expansion of heathlands. Based on this P. uncinata case, we discuss how local extinctions can affect management and conservation policies negatively.     

MALDI-TOF, HPLC-ESI-TOF and 13C-NMR characterization of chestnut (Castanea sativa) shell tannins for wood adhesives

MALDI-TOF, HPLC-ESI-TOF and 13C-NMR techniques were used to analyse the structure of non-purified aqueous chestnut shell tannin extracts. In addition, the influence of the extraction agent (water or aqueous solutions of Na₂SO₃ and/or NaOH) on tannin structure was analysed by MALDI-TOF in order to select the extract with the best properties for wood adhesives. Using HPLC-ESI-TOF, catechin/epicatechin, gallocatechin/epigallocatechin, dicatechin structures, dicatechin structures without a hydroxyl group, galloyl-glucoses and ellagic acid were identified as the main monomeric components in the aqueous extract. 13C-NMR and MALDI-TOF spectra revealed that extracts are mostly composed of procyanidin and prodelphinidin structures although prorobinetidins might be also present. MALDI-TOF spectrometry was used to identify the extract oligomeric components. Extractions with Na₂SO₃ and/or NaOH produced changes in the predominant structures in the extracts and on the amount of sugar units linked to the flavonoid structures, which decreased in the presence of Na₂SO₃. Extract obtained using low Na₂SO₃ and NaOH concentrations (1.5 and 0.75 %, respectively) was selected as more suitable for wood adhesive preparation.