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排序方式: 共有110条查询结果,搜索用时 31 毫秒
31.
During 2 years, a melon crop (Cucumis melo L. cv. Sancho) was grown under field conditions to investigate the effects of different nitrogen (N) and irrigation (I) levels on fruit yield, fruit quality, irrigation water use efficiency (IWUE) and nitrogen applied efficiency (NAE). The statistical design was a split-plot with four replications, where irrigation was the main factor of variation and N was the secondary factor. In 2005, irrigation treatments consisted of applying daily a moderate water stress equivalent to 75% of ETc (crop evapotranspiration), a 100% ETc control and an excess irrigation of 125% ETc (designated as I75, I100 and I125), while the N treatments were 30, 85, 112 and 139 kg N ha−1 (designated as N30, N85, N112 and N139). In 2006, both the irrigation and N treatments applied were: 60, 100 and 140% ETc (I60, I100 and I140) and 93, 243 and 393 kg N ha−1 (N93, N243 and N393). Moderate water stress did not reduce melon yield and high IWUE was obtained. Under severe deficit irrigation, the yield was reduced by 22% mainly due to decrease fruit weight. The relative yield (yield/maximum yield) was higher than 95% when the irrigation depth applied was in the range of 87-136% ETc. In 2006, the interaction between irrigation and N was significant for yield, fruit weight and IWUE. The best yield, 41.3 Mg ha−1, was obtained with 100% ETc at N93. The flesh firmness and the placenta and seeds weight increased when the irrigation level was reduced by 60% ETc. The highest NAE was obtained with quantities of water close to 100% ETc and increased as the N level was reduced. The highest IWUE was obtained with applications close to 90 kg N ha−1. The I243 and I393 treatments produced inferior fruits due to higher skin ratios and lower flesh ratios. These results suggest that it is possible to apply moderate deficit irrigation, around 90% ETc, and reduce nitrogen input to 90 kg ha−1 without lessening quality and yields. 相似文献
32.
Continuous infusion of thyroid hormones during the last 12 days of gestation in ovine fetuses was associated with: a reduction of the rate of appearance of blood IgG1 after colostrum feeding in the newborn lambs; an important reduction of the number of jejunal cells filled with IgG1, 12 hours post partum, suggesting a premature closure of the intestinal permeability to IgG1; and a significant reduction of the K99+ Escherichia coli adhesion on the intestinal villi. These results could partly explain relationships observed previously between perinatal thyroid function abnormalities and the occurrence of neonatal diseases. 相似文献
33.
Rolando A. Flores Carol W. Shanklin Mariano Loza-Garay Seung H. Wie 《Compost science & utilization》2013,21(1):63-71
A survey was undertaken to determine the wastes/residues generated by the food processing industry in the state of Iowa by sending a questionnaire to food processors with more than ten employees. Food processors were asked to provide a company profile, information about food waste/residue generated, and information about current disposal methods. Samples of wastes/residues were obtained from food processors willing to provide them, and proximate analysis was done. The overall response rate was 82.2 percent or 365 respondents out of 444 questioned. Companies under different category of standard industrial code (SIC) could produce similar wastes/residues that were classified in the same waste/residue streams. Within the meat and seafood category, the majority (87.7 percent) of the wastes/residues were generated by SIC codes 2077 (animal, marine fats and oils) and 2015 (poultry slaughtering, dressing, and processing). Among the waste management practices reported, excluding “other,” land application accounted for 14.0 percent of the waste stream, followed by rendering with 11.4 percent, landfill with 6.7 percent, sewage on-site with 5.0 percent and animal feed production off-site with 4.3 percent. Other waste management practices (combinations of major practices or others not clearly defined) account for 55.1 percent of the allocation of the waste stream. 相似文献
34.
Basilio Carrasco Patricio Avila Jorge Perez-Diaz Patricio Muñoz Rolando García Blas Lavandero Andrés Zurita-Silva Jorge B. Retamales Peter D. S. Caligari 《Genetic Resources and Crop Evolution》2009,56(3):331-337
In Chile Vasconcellea pubescens is cropped to produce canned fruit, juice, jam and processed sweets. Additionally this species produces latex with a high
level of papain, an important and valuable proteolytic enzyme with industrial applications. In this investigation seven ISSR
primers were used to study the level and organization of genetic diversity in 333 samples of V. pubescens. Out of the 114 bands recorded, 63 proved to be polymorphic (P = 55.3%). At the species level, the genetic diversity was rather low (h = 0.01 ± 6,80188E-05, Shannon’s Index I = 0.16 ± 0,000148). The major portion of the genetic diversity was found within groups (65%). The genetic differentiation
between the different groups was significant, as the AMOVA analysis suggested (Φpt = 0.35). When analysing the Northern area alone, the differentiation increased to Φpt = 0.40. When only the Southern area was analysed, Φpt decreased to 0.18, indicating greater genetic similarity among the samples. The results generated from Structure and Bayesian
Analysis of Population Structure distinguished 8 genetically different groups, five of them located in the north and three
in the south. The results are discussed in the light of the growers’ practices. 相似文献
35.
This paper investigates the distribution of arbuscular mycorrhizal fungi (AMF) spores and AMF colonization in a field study
in southeastern Brazil. Response to AMF and rhizobial inoculation was studied in monocultures of Plathymenia reticulata and mixed plantations with both Tabebuia heptaphylla and Eucalyptus camaldulensis in a sandy soil during two consecutive years. P. reticulata height and diameter and mycorrhizal colonization and AMF diversity were measured in dry and rainy periods. The inoculated
treatment of E. camaldulensis, T. heptaphylla and P. reticulata mixed plants showed higher height and diameter growth of P. reticulata used as well as increased root colonization and AMF spore numbers. Spore populations were found to belong to five genera:
Acaulospora, Entrophospora, Glomus, Gigaspora and Scutellospora, with Glomus dominating. Agroforestry practices including use of leguminous tree P. reticulata effectively maintained AMF spore numbers in soils and high AMF colonization levels compared with monocultures, proving an
efficient system for productivity and sustainability. 相似文献
36.
Marcela C. Pagano Marta N. Cabello Antonio F. Bellote Nadja M. Sá Maria Rita Scotti 《Agroforestry Systems》2008,74(3):231-242
For the purpose of reforestation and wood supply the leguminous tree Anadenanthera peregrina, a native species, was intercropped with Eucalyptus camaldulensis in a degraded semiarid area of Brazil. Single and mixed stands of these species were inoculated with Rhizobium and/or arbuscular mycorrhizal fungi (AMF). The growth of all species in mixed stands did not differ from those cultivated
in monoculture and land equivalent ratio (LER) exceeded unity in intercropped plots. Inoculated plants showed greater height
and diameter growth and dry matter and nutrient concentration in plants of A. peregrina was higher in inoculated single plots. The distribution, composition and density of AMF species was related to the rhizosphere
effect of plant species. The intercropped model where all the plants were inoculated achieved soil AMF diversity patterns
similar to those of the preserved area and showed also higher soil organic matter, nutrient content as well as a reduction
in soil macroporosity. This model of intercropping may be considered as an efficient system for reforestation under semiarid
conditions. 相似文献
37.
María A. Jaworski Guillermo R. Bertolini Carmen I. Cabello Guillermo J. Siri Mónica L. Casella 《Water, air, and soil pollution》2018,229(9):309
The investigation and development of technologies to remediate water contaminated with NO3? are constantly increasing. An economically and potentially effective alternative is based on the catalytic hydrogenation of NO3? to N2. With this objective, bimetallic RhMo6 catalysts based on Anderson-type heteropolyanion (RhMo6O24H6)3? were prepared and characteri3ed in order to obtain well-defined bimetallic catalyst. The catalysts were supported on Al2O3 with different textural properties and on silica. The heteropolyanion-support interaction was analysed by temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). The differences obtained in activity and selectivity to the different products can be assigned to the different interaction between the RhMo6 Anderson phase and the supports. The RhMo6/G, (G: γ-Al2O3) system showed the best catalytic performance. This catalyst exhibited the lowest reduction temperature of Rh and Mo in the TPR assay and a Rh/Mo surface ratio similar to that of the original phase, as observed by XPS analysis. These studies allowed us to verify a synergic effect between Rh and Mo, through which Mo reducibility was promoted by the presence of the noble metal. The catalytic activity was favoured by the active sites generated from the Anderson phase. This fact was confirmed by comparing the activity of RhMo6/G with that corresponding to a conventional catalyst prepared through successive impregnation of both Rh (III) and Mo (VI) salts. 相似文献
38.
39.
Nicolas Desneux Eric Wajnberg Kris A. G. Wyckhuys Giovanni Burgio Salvatore Arpaia Consuelo A. Narváez-Vasquez Joel González-Cabrera Diana Catalán Ruescas Elisabeth Tabone Jacques Frandon Jeannine Pizzol Christine Poncet Tomás Cabello Alberto Urbaneja 《Journal of pest science》2010,83(3):197-215
The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest of tomato originating from South America. After its initial detection in eastern Spain in 2006, it rapidly invaded various other European countries and spread throughout the Mediterranean basin. If no control measures are taken, then the pest can cause up to 80–100% yield losses in tomato crops in recently invaded areas and may pose a threat to both greenhouse and open-field tomato production. The exceptional speed and extent of T. absoluta invasion have called for studies documenting its biology and ecology, while indicating an urgent need for efficient and sustainable management methods. The development of approaches to manage T. absoluta would be facilitated through a detailed revision of information on this pest in its area of origin. This review combines information on the invasion by T. absoluta, its ecology, and potential management strategies, including data that may help the implementation of efficient biological control programs. These programs, together with a variety of other management tactics, may allow efficient integrated pest management of T. absoluta in Europe and Mediterranean Basin countries. 相似文献
40.
Using the age shift method to determine gains from weed management for Pinus radiata in New Zealand
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Understanding the effects of interspecific competition on long‐term growth of plantation forestry crops is critical to forest management decisions around methods used for weed control. A series of permanent sample plots (31) incorporating trees maintained either weedy or weed‐free until canopy closure were established across New Zealand between 2000 and 2002. We used the age shift method to characterise growth responses of Pinus radiata, in New Zealand, to interspecific competition over the first third of a typical rotation. Eight years after planting, age shifts between treatments ranged between ?0.60 years and +3.07 years. On average, the age shift due to weed control increased from 0.62 to 0.96 years between 4 and 8 years of age. This was due to divergent tree growth between weedy and weed‐free plots at 55% of the sites, while at 32% and 13% of sites, respectively, differences between treatments remained constant or decreased beyond age 4 years. The magnitude of the age shift was found to be related to the type of weed dominating early interspecific competition, with woody weeds associated with significantly greater age shifts. Continued divergence in tree growth between weedy and weed‐free treatments up to 8 years after planting at the majority of sites was an unexpected result and contrasts with previous literature. In situations where growth divergence continues beyond 2 years, managers should consider continued treatment of weeds to mitigate the detrimental impacts of on‐going competition. 相似文献