Tree effects on the chemical topsoil features of oak, beech and pine forests     

Elena Marcos  Leonor Calvo  José Antonio Marcos  Ángela Taboada  Reyes Tárrega 《European Journal of Forest Research》2010,129(1):25-30

We aimed to study tree effects on the chemical properties of forest soils. We compared soil features of three types of forest ecosystems, each with four stands (replicates): beech forests (Fagus sylvatica), oak forests (dominated by Quercus pyrenaica) and pine plantations (Pinus sylvestris). Five samples from the top 10 cm of soil were taken per stand, from which pH, organic matter content (O.M.), total nitrogen (N) and available calcium (Ca²⁺), magnesium (Mg²⁺), potassium (K⁺) and sodium (Na⁺) were determined. Litter layer depth was measured at each soil sampling point. We also measured tree density and crown diameters at each stand. Our results indicated that soil samples from the four pine plantation stands were more similar while oak and beech stands were characterised by great variability in terms of soil properties and leaf litter depth. Although the identity of the dominant tree species significantly influenced several topsoil chemical properties (increase in pH and available cations in oak forests and higher organic matter and total nitrogen in beech and pine ecosystems), there were other important factors affecting soil features that may be taken under consideration. Differences between soil properties of the three types of forest ecosystems were mainly related to the characteristics of the litter layer and less related to the tree layer structure. Finally, the establishment of pine plantations in naturally deciduous tree areas made the topsoil features more homogeneous.  相似文献   

Determination of the prevalence and severity of metacarpophalangeal joint osteoarthritis in Thoroughbred racehorses via quantitative macroscopic evaluation     

Neundorf RH  Lowerison MB  Cruz AM  Thomason JJ  McEwen BJ  Hurtig MB 《American journal of veterinary research》2010,71(11):1284-1293

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Participatory organic certification in Mexico: an alternative approach to maintaining the integrity of the organic label     

Erin Nelson  Laura Gómez Tovar  Rita Schwentesius Rindermann  Manuel Ángel Gómez Cruz 《Agriculture and Human Values》2010,27(2):227-237

Over the past two decades the growth of the organic sector has been accompanied by a shift away from first party, or peer review, systems of certification and towards third party certification, in which a disinterested party is responsible for the development of organic standards and the verification of producer compliance. This paper explores some of the limitations of the third party certification model and presents the case of Mexico as an example of how an alternative form of participatory certification has emerged. The paper suggests that participatory guarantee systems (PGS) are reflective of the growing “beyond organic” movement, which focuses on reconstructing the local and re-embedding food systems into their socio-ecological contexts. It argues that PGS offers a number of benefits for producers and consumers, particularly in the South, but that it faces a number of challenges as well, such as a lack of formal recognition, social conflicts and dependence on donated resources.  相似文献   

Growth performance of juvenile pacu (Piaractus mesopotamicus) and dourado (Salminus brasiliensis) fed with lyophilized bovine colostrum          下载免费PDF全文

Raul Machado‐Neto  Debora Botequio Moretti  Wiolene Montanari Nordi  Thaline Maira Pachelli da Cruz  José Eurico Possebon Cyrino 《Aquaculture Research》2016,47(11):3551-3557

Growth performance was evaluated in juvenile pacu (Piaractus mesopotamicus) and dourado (Salminus brasiliensis) fed diets containing 0%, 10% and 20% of lyophilized bovine colostrum for 60 days. The performance variables of weight gain, relative weight gain, feed intake, feed conversion ratio, specific growth rate, total protein intake and protein efficiency ratio were evaluated as well as apparent digestibility coefficients of protein and energy in the diets. Inclusion of bovine colostrum did not induce differences in the performance of pacu and dourado (P > 0.05), indicating that the diets were adequate and met the nutritional needs of the juveniles. The protein digestibility in both species was improved with the inclusion of the bovine lacteal secretion. Based on the variables studied, the diets with lyophilized bovine colostrum inclusion were nutritionally suitable for both pacu and dourado indicating the possibility to use this lacteal secretion as a partial substitute of dietary protein.  相似文献   

Response to the insecticide chlorpyrifos by arthropods on maize canopy     

M. Michereff Filho  T. M. C. Della Lucia  I. Cruz  R. N. C. Guedes 《国际虫害防治杂志》2013,59(3):203-210

We assessed the response of maize canopy arthropods to the insecticide chlorpyrifos. Four 0.3 ha (18 2 180 m) plots were divided into two subplots, a control and a treated area. During tasseling of the plants, the treated area was sprayed twice, with an interval of 3 days. Ten plants were sampled: 1 day before spraying, and 7, 14, 21 and 28 days after spraying. The insecticide had no effect on insect herbivores: a high density of Spodoptera frugiperda larvae was present in the treated plots. A few predator arthropod species were negatively affected by the insecticide, but their numbers or activity increased 2 weeks after the treatment of the plots. A canonical variate analysis showed no pronounced effect of the insecticide on arthropod communities; the largest variations on species abundance were related to sampling occasion. These results can be explained by the combination of the short period of chlorpyrifos residual activity on the plant surface and the great potential for recolonization of the areas by most of the monitored arthropods.  相似文献   

Genetic diversity of selected pigmented traditional rice (Oryza sativa L.) varieties from Mindanao,Philippines using agromorphological traits and simple sequence repeats markers     

Embate  Mary Valerie G.  Calayugan  Mark Ian C.  Gentallan  Renerio P.  Sta Cruz  Pompe C.  Hernandez  Jose E.  Borromeo  Teresita H. 《Journal of Crop Science and Biotechnology》2021,24(3):259-277

Journal of Crop Science and Biotechnology - Philippine pigmented traditional rice varieties (TRVs) offer potential novel genes for genetic improvement. In this study, forty-three pigmented...  相似文献   

Study of the synergistic effects of salinity, pH, and temperature on the surface-active properties of biosurfactants produced by Lactobacillus pentosus     

Bello XV  Devesa-Rey R  Cruz JM  Moldes AB 《Journal of agricultural and food chemistry》2012,60(5):1258-1265

Many studies have investigated the effects of pH, temperature, and salinity on the surface-active properties of various surfactants, although in most cases the variables have been studied separately, without considering the effects of any interactions between them. In the present study, a Box-Behnken factorial design was applied to study the effects of pH, temperature, and salinity on the surface-active properties of a biosurfactant produced by Lactobacillus pentosus. The data obtained enabled development of a second-order model describing the interrelationships between operational and experimental variables, by equations including linear, interaction, and quadratic terms. The variable that had the greatest effect on the surface-active properties of the biosurfactant was pH. Moreover, at pH 3-5.5, decreases in salinity and temperature acted synergistically, reducing the surface tension of the biosurfactant; at pH 8, the same effect was observed with increasing salinity and temperature.  相似文献   

Late Pleistocene ‐ Holocene palaeosols in the north of Sonora,Mexico: chronostratigraphy,pedogenesis and implications for environmental history     

T. Cruz‐y‐Cruz  S. Sedov  G. Sánchez  T. Pi‐Puig  K. Pustovoytov  H. Barceinas‐Cruz  B. Ortega‐Guerrero  E. Solleiro‐Rebolledo 《European Journal of Soil Science》2014,65(4):455-469

Red palaeosols of the late Pleistocene‐early Holocene, both buried and non‐buried, were studied recently in Sonora (NW Mexico) to reconstruct their pedogenesis as well as the palaeoenvironmental conditions. The alluvial palaeosol‐sedimentary sequence of the La Playa archaeological site is a key locality for the buried San Rafael palaeosol, which exhibits a 2Ah‐2Bw‐2BCk‐3Bgk profile and was defined as a Chromic Cambisol. Radiocarbon dates from pedogenic carbonates and charcoal set the soil formation interval between > 18 000 and 4300 calibrated years before present (cal. year BP). Micro‐morphological observations together with profile distribution of clay, carbonates, organic carbon, pedogenic iron oxides and rock magnetic properties indicated a strong eluvial‐illuvial redistribution of carbonates, moderate silicate weathering and gleying in the lower horizon. Although this soil was much more developed than the overlying syn‐sedimentary late Holocene Fluvisols, clay mineral composition and stable carbon isotope signatures of humus and carbonates were similar in both soils. We suggest that pedogenesis of the San Rafael palaeosol took place under a slightly more humid climate and relative geomorphic stability. This agrees with the regional palaeoclimate reconstruction, which indicates a moister climate during the Late Wisconsin glaciation (MIS 2). An abrupt termination of the San Rafael pedogenesis marked by disturbance and aridization features in the Ap horizon of the palaeosol could be linked to a global drought around 4200 years cal. year BP. Surface Chromic Cambisols in northern Sonora show similar pedogenetic characteristics to the buried red palaeosols of La Playa. They appear to be a relict component of the present day soil mantle.  相似文献   

Antioxidant activity of uruguayan propolis. In vitro and cellular assays     

Silva V  Genta G  Möller MN  Masner M  Thomson L  Romero N  Radi R  Fernandes DC  Laurindo FR  Heinzen H  Fierro W  Denicola A 《Journal of agricultural and food chemistry》2011,59(12):6430-6437

The antioxidant capacity of propolis from the southern region of Uruguay was evaluated using in vitro as well as cellular assays. Free radical scavenging capacity was assessed by ORAC, obtaining values significantly higher than those of other natural products (8000 μmol Trolox equiv/g propolis). ORAC values correlated well with total polyphenol content (determined by Folin-Ciocalteu method) and UV absorption. Total polyphenol content (150 mg gallic acid equiv/g propolis) and flavonoids (45 mg quercetin equiv/g propolis) were similar to values reported for southern Brazilian (group 3) and Argentinean propolis. Flavonoid composition determined by RP-HPLC indicates a strong poplar-tree origin. Samples high in polyphenols efficiently inhibit low-density lipoprotein lipoperoxidation and tyrosine nitration. In addition, Uruguayan propolis was found to induce the expression of endothelial nitric oxide synthase and inhibit endothelial NADPH oxidase, suggesting a potential cardiovascular benefit by increasing nitric oxide bioavailability in the endothelium.  相似文献   

Changes in hoof surface strain distribution in response to moderate exercise in Standardbreds     

Faramarzi B  Cruz AM  Sears WC 《American journal of veterinary research》2011,72(4):484-490

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