Reference bulk density and critical degree-of-compactness for no-till crop production in subtropical highly weathered soils     

Jos Miguel Reichert  Luis Eduardo Akiyoshi Sanches Suzuki  Dalvan Jos Reinert  Rainer Horn  Inge Hkansson 《Soil & Tillage Research》2009,102(2):242

The concept of degree of compactness (DC), referred to as field bulk density (BD) as a percentage of a reference bulk density (BD_ref), was developed to characterize compactness of soil frequently disturbed, but for undisturbed soil such as under no-tillage critical degree of compactness values have not been tested. The objective of this study was to compare methods to determine BD_ref and limits of DC and BD for plant growth under no-tillage in subtropical soils. Data from the literature and other databases were used to establish relationships between BD and clay or clay plus silt content, and between DC and macroporosity and yield of crops under no-tillage in subtropical Brazil. Data of BD_ref reached by the soil Proctor test on disturbed soil samples, by uniaxial compression with loads of 200 kPa on disturbed and undisturbed soil samples, and 400, 800 and 1600 kPa on undisturbed soil samples, were used. Also, comparisons were made with critical bulk density based on the least limiting water range (BDc LLWR) and on observed root and/or yield restriction in the field (BDc Rest). Using vertical uniaxial compression with a load of 200 kPa on disturbed or undisturbed samples generates low BD_ref and high DC-values. The standard Proctor test generates higher BD_ref-values, which are similar to those in a uniaxial test with a load of 1600 kPa for soils with low clay content but lower for soils with high clay content. The BDc LLWR does not necessarily restrict root growth or crop yield under no-tillage, since field investigations led to higher BDc Rest-values. A uniaxial load greater than 800 kPa is promising to determine BD_ref for no-tillage soils. The BD_ref is highly correlated to the clay content and thus pedotransfer functions may be established to estimate the former based on the latter. Soil ecological properties are affected before compaction restricts plant growth and yield. The DC is an efficient parameter to identify soil compaction affecting crops. The effect of compaction on ecological properties must also be further considered.  相似文献   

Modeling soil organic carbon dynamics in Oxisols of Ibirubá (Brazil) with the Century Model     

Carlos Gustavo Tornquist  Joo Mielniczuk  Carlos Eduardo Pellegrino Cerri 《Soil & Tillage Research》2009,105(1):33-43

Introduction of conservation practices in degraded agricultural land will generally recuperate soil quality, especially by increasing soil organic matter. This aspect of soil organic C (SOC) dynamics under distinct cropping and management systems can be conveniently analyzed with ecosystem models such as the Century Model. In this study, Century was used to simulate SOC stocks in farm fields of the Ibirubá region of north central Rio Grande do Sul state in Southern Brazil. The region, where soils are predominantly Oxisols, was originally covered with subtropical woodlands and grasslands. SOC dynamics was simulated with a general scenario developed with historical data on soil management and cropping systems beginning with the onset of agriculture in 1900. From 1993 to 2050, two contrasting scenarios based on no-tillage soil management were established: the “status quo” scenario, with crops and agricultural inputs as currently practiced in the region and the “high biomass” scenario with increased frequency of corn in the cropping system, resulting in about 80% higher biomass addition to soils. Century simulations were in close agreement with SOC stocks measured in 2005 in the Oxisols with finer texture surface horizon originally under woodlands. However, simulations in the Oxisols with loamy surface horizon under woodlands and in the grassland soils were not as accurate. SOC stock decreased from 44% to 50% in fields originally under woodland and from 20% to 27% in fields under grasslands with the introduction of intensive annual grain crops with intensive tillage and harrowing operations. The adoption of conservation practices in the 1980s led to a stabilization of SOC stocks followed by a partial recovery of native stocks. Simulations to 2050 indicate that maintaining “status quo” would allow SOC stocks to recover from 81% to 86% of the native stocks under woodland and from 80% to 91% of the native stocks under grasslands. Adoption of a “high biomass” scenario would result in stocks from 75% to 95% of the original stocks under woodlands and from 89% to 102% in the grasslands by 2050. These simulations outcomes underline the importance of cropping system yielding higher biomass to further increase SOC content in these Oxisols. This application of the Century Model could reproduce general trends of SOC loss and recovery in the Oxisols of the Ibirubá region. Additional calibration and validation should be conducted before extensive usage of Century as a support tool for soil carbon sequestration projects in this and other regions can be recommended.  相似文献   

Extramedullary plasmacytoma of the third eyelid gland in a dog     

Eduardo Perlmann  Maria L. Z. Dagli  Maria C. Martins†  Sheila A. C. Siqueira‡  Paulo S. M. Barros 《Veterinary ophthalmology》2009,12(2):102-105

A case of extramedullary plasmacytoma of the third eyelid gland in a 7-year-old American Cocker Spaniel is reported. An enlargement of the third eyelid gland, abundant mucopurulent discharge, mild hyperemia and corneal pigmentation in the OD was present. Excisional biopsy of the mass revealed the gland was infiltrated and partially destroyed by a uniform population of neoplastic plasma cells. The neoplastic cells were positive for CD138, Ki-67 and λ light chain. CD20, CD3, κ light chain and cytokeratin were negative. Twelve months following surgery, no recurrence was observed. To the authors' knowledge, this is the first extramedullary plasmacytoma of the third eyelid gland reported in dogs.  相似文献   

A combination of Lactobacillus buchneri and Pediococcus pentosaceus extended the aerobic stability of conventional and brown midrib mutants–corn hybrids ensiled at low dry matter concentrations by causing a major shift in their bacterial and fungal community     

Juan J Romero  Jin Park  Younghoo Joo  Yuchen Zhao  Marjorie Killerby  Diana C Reyes  Francesco Tiezzi  Eduardo Gutierrez-Rodriguez  Miguel S Castillo 《Journal of animal science》2021,99(8)

We evaluated the effects of applying a combination inoculant to four corn hybrids harvested at high moisture on their nutritive value and microbial populations. The treatment design was the factorial combination of corn hybrids ensiled with (INO) and without (CON) inoculant. The hybrids were TMF2R737 (MCN), F2F817 (MBR), P2089YHR (PCN), and PI144XR (PBR), ensiled at dry matter (DM) concentrations of 30.5%, 26.3%, 31.1%, and 31.5%, respectively; MBR and PBR were brown midrib mutants (BMR). The inoculant contained Lactobacillus buchneri and Pediococcus pentosaceus (4 × 10⁵ and 1 × 10⁵ cfu/g of fresh corn). The experiment had a complete randomized design with treatments replicated six times. Corn was treated or not with inoculant, packed into 7.6 L bucket silos, and stored for 100 d. At d 0, the relative abundance (RA, %) of Enterobacteriaceae was lower in PBR vs. the other hybrids [51.3 vs. x¯ = (average of) 58.4] and in the case of fungi, incertae sedis (i.s.) Tremellales and Mucoraceae were more and less abundant, respectively, in conventional hybrids vs. BMRs (x¯= 25.8 vs. x¯ = 13.9 and x¯ = 3.64 vs. x¯ = 7.52; P < 0.04). After ensiling, INO had higher LAB (9.3 vs. 7.1 log cfu/g of fresh corn) and acetic acid (3.44% vs. 1.32% of DM) and lower yeast (3.1 vs. 4.6) and molds (1.5 vs. 3.0), and also extended the aerobic stability (582 vs. 111 h) but decreased DM recovery (95.6% vs. 97.4%) vs. CON (P < 0.02). Inoculation reduced bacterial phylogenetic diversity (6.75 vs. 14.4) but increased fungal observed taxonomical units (46 vs. 20) vs. CON (P < 0.01). Also, a higher relative abundance (RA) for Lactobacillaceae (99.2% vs. 75.7%) and lower for Enterobacteriaceae (0.28 vs. 9.93) was observed due to inoculation (P < 0.001). For fungi, INO had a lower RA compared to CON for Monascaceae (12.6 vs. 44.7) and increased i.s. Tremellales (8.0 vs. 1.2) and i.s. Saccharomycetales (6.4% vs. 0.3%; P < 0.006). Inoculation changed the diverse bacterial community found in the phyllosphere across hybrids to a taxonomically uneven one dominated by Lactobacillaceae. In the case of fungi, INO application increased the fungal diversity at d 100 mainly by reducing the dominance of Monascaceae vs. CON. In conclusion, the INO treatment overwhelmed the disparate microbial populations found across BMR and conventional hybrids ensiled at low DM concentrations and ensured a significant concentration of acetic acid that modified fungal populations and in turn extended the aerobic stability of all hybrids.  相似文献   

The fate of arsenic in soils adjacent to an old mine site (Bustarviejo,Spain): mobility and transfer to native flora     

Eduardo Moreno-Jiménez  Rebeca Manzano  Elvira Esteban  Jesús Peñalosa 《Journal of Soils and Sediments》2010,10(2):301-312

Background, aim, and scope  

The mobility of arsenic in soils and its transfer to other environmental components present significant environmental risks. The management of polluted land is determined by the availability, mobility, and transfer of inorganic pollutants to different ecosystem compartments. In this paper, the fate of arsenic at this mining site has been evaluated to determine future management practises to minimise such risk.  相似文献   

Contrasting phenology and female cone characteristics of the two Macaronesian island endemic cedars (<Emphasis Type="Italic">Juniperus cedrus</Emphasis> and <Emphasis Type="Italic">J. brevifolia</Emphasis>)     

Beatriz Rumeu  Manuel Nogales  Rui B. Elias  David P. Padilla  Tiago Resendes  Airam Rodríguez  Francisco Valdés  Eduardo Dias 《European Journal of Forest Research》2009,128(6):567-574

Phenology and female cone characteristics of the two endemic cedars (Juniperus cedrus and J. brevifolia) from the Macaronesian islands were studied. Despite their closely taxonomic affinity and their evolution under insular conditions, different trends were recorded. Mature J. cedrus female cones were present throughout the year, while those from J. brevifolia were only present in summer and autumn. J. cedrus female cone size was significantly larger than that of J. brevifolia, a trend consistent with the presence of larger vertebrates (lizards and birds) in the Canary Islands. However, water content was four times higher in J. brevifolia female cones, which can be related with the higher rainfall existing in the Azores. J. cedrus has two or three seeds per cone, whereas J. brevifolia frequently had three. Seeds from J. cedrus were clearly larger and heavier, coinciding with the female cone size trend. However, tetrazolium tests revealed higher viability values in J. brevifolia. The relatively low percentage of filled seeds in J. cedrus could be a consequence of the climatic stress and limits to pollination due to fragmented populations as described for other Juniperus species. In summary, our results reveal that some environmental factors such as the harsh conditions, high population fragmentation and the dependence on large dispersers have compromised the fitness of J. cedrus in the Canary Islands.  相似文献   

Users’ Reactions to the Primer on Tree Registration Policies: Lessons for Designing Extension Materials and Improving Information Flow     

Rotacio Gravoso  Eduardo Mangaoang  Maria Anabelle Gerona  Arturo Pasa  Steve Harrison 《Small-Scale Forestry》2009,8(3):275-287

In the Philippines, only a few farmers and plantation owners register their tree farms with the Department of Environment and Natural Resources (DENR), the office in charge of tree registration. One of the major reasons is their lack of knowledge of government policy on tree registration. To help improve the flow of information and understanding of tree registration policies among smallholder tree farmers and other stakeholders, a Primer on Tree Registration, Harvesting, Transport and Marketing Policies on Private Land was developed. Produced through the participation of stakeholders, including tree farmers, the DENR, and local government officers, police, and timber dealers, the Primer is highly visual and has been released in English as well as Waray–Waray and Cebuano dialects. This paper reports findings of focus group discussions conducted to gauge user reactions to the Primer. The Primer was considered as a valuable source of information about tree registration policies. Aside from being comprehensible, FGD participants found it attractive, perceived it to be intended for them and free from content that confused them. However, farmers suggested that illustrations need to be improved by making the persons portrayed more presentable and reflective of their actual tree farm operations. Participants said that aside from the Primer, the flow of information on tree registration policies could be improved through the use of multi-media including posters, radio broadcasts, and presentation in seminars for farmers.  相似文献   

Path analysis for selection of drought tolerant sugarcane genotypes through physiological components     

Paulo Pedro da Silva  Lailton SoaresJoão Gomes da Costa  Luciana da Silva VianaJúlio César Farias de Andrade  Eduardo Rebelo GonçalvesJoão Messias dos Santos  Geraldo Veríssimo de Souza BarbosaVelber Xavier Nascimento  Adriana Reis TodaroAlessandro Riffel  Maria Fatima Grossi-de-SaMárcio Henrique Pereira Barbosa  Antônio Euzébio Goulart Sant’AnaCícero Eduardo Ramalho Neto 《Industrial Crops and Products》2012,37(1):11-19

Water deficit is among the main environmental factors limiting agricultural productivity of sugarcane in Northeast Brazil by affecting virtually every aspect of plant growth, with consequent reduction of the agro-industrial productivity of this crop. This study aimed to use path analysis to evaluate the physiological components of sugarcane under two water conditions, with photosynthesis as the basic variable, in order to obtain subsidies that can help the genetic breeding of this crop by selection of superior clones with drought tolerance. The experiment was carried out in a greenhouse with a completely randomized experimental design, 4 × 2 factorial arrangements (four sugarcane genotypes × two soil moisture regimes: control, with 80-100% available water and stressed, with 0-20% water available) and with four replications. Each plot consisted of one pot with 12 kg of substrate containing one plant. Treatments were maintained at a humidity close to field capacity with daily replacement of the evapotranspired water with a water supply for 66 days of cultivation for treatments under stress. Evaluations were conducted on the fourth day after severe water stress at 70 days of cultivation. Data from nine physiological variables were considered, with six of these being used in the model after exclusion of those that were contributing to multicollinearity. Variables used in path analysis were enough to explain the variation found in photosynthesis under both water conditions. Stomatal conductance, transpiration and the SPAD index should be considered as a priority in breeding programs for sugarcane aiming to get more productive and tolerant genotypes to water stress, and selection indexes should be used with due consideration of these variables to promote gains in photosynthesis.  相似文献   

Temperature and storage period over spermatic parameters of jundiá, Rhamdia quelen (Quoy & Gaimard, 1824)     

Eduardo Antônio Sanches  Giovano Neumann  César Pereira Rebechi de Toledo  Robie Allan Bombardelli  Pitágoras Augusto Piana  Elizabeth Romagosa 《Aquaculture Research》2013,44(4):534-541

The aim of this work was to evaluate the spermatic parameters of jundia, Rhamdia quelen, semen stored for short periods under different temperatures. Fifteen males were used in a time factorial experimental design (13 × 3 × 3 × 3). The sperm was stored at: 15; 25 and 35°C and activated in water at: 15; 25 and 35°C each, respectively, within storage periods of: 0; 2; 4; 6; 8; 10; 12; 16; 20; 24; 32; 40 and 48 h after collection. The treatments were performed in triplicates and in sequential protocols every 50 h. The motility parameters were evaluated using Pearson's correlation analysis and the significant parameters (P < 0.05) were summarized using principal component analysis forming two predicted groups. Group 01 composed the following parameters: curvilinear velocity, wobble and linearity; group 02 comprised average path velocity, straight line velocity, beating cross frequency and motility rate. Effects (P < 0.05) of treatments were observed only in group 02, with interaction between time and temperature of exposure and between exposure time and water temperature. Superior results of spermatic parameters of group 02 were observed right after collection. However, the exposure and spermatic activation at 15°C assured significant results 48 h after collection when compared with 25 and 35°C.  相似文献   

Physical and Sensory Properties of Regular and Reduced‐Fat Pound Cakes with Added Amaranth Flour     

Vanessa Dias Capriles  Eveline Lopes Almeida  Reinaldo Eduardo Ferreira  Jos Alfredo Gomes Arêas  Caroline Joy Steel  Yoon Kil Chang 《Cereal Chemistry》2008,85(5):614-618

The sum of wheat flour and corn starch was replaced by 10, 20, or 30% whole amaranth flour in both conventional (C) and reduced fat (RF) pound cakes, and the effects on physical and sensory properties of the cakes were investigated. RF presented 33% fat reduction. The increasing amaranth levels darkened crust and crumb of cakes, which decreased color acceptability. Fresh amaranth‐containing cakes had similar texture characteristics to the controls, evaluated both instrumentally and sensorially. Sensory evaluation revealed that replacement by 30% amaranth flour decreased C cakes overall acceptability scores, due to its lower specific volume and darker color. Amaranth flour levels had no significant effect on overall acceptability of RF cakes. Hence, the sum of wheat flour and corn starch could be successfully replaced by up to 20% amaranth flour in C and up to 30% in RF pound cakes without negatively affecting sensory quality in fresh cakes. Moisture losses for all the cakes were similar, ≈1% per day during storage. After six days of storage, both C and RF amaranth‐containing cakes had higher hardness and chewiness values than control cakes. Further experiments involving sensory evaluation during storage are necessary to determine the exact limit of amaranth flour replacement.  相似文献