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Chunyan Liu Jirko Holst Zhisheng Yao Nicolas Brüggemann Klaus Butterbach-Bahl Shenghui Han Xingguo Han Xunhua Zheng 《Agriculture, ecosystems & environment》2009,134(1-2):136-142
We investigated nitric oxide (NO) fluxes at a summer and a winter sheepfold in the Baiyinxile livestock farm, near Xilinhot, Inner Mongolia, which are a typical feature of the regional husbandry. Using a manual static opaque chamber/chemiluminescence measuring system, we intermittently observed fluxes in the summer sheepfold between May 28th and September 26th 2005 and in both winter and summer sheepfolds between March 8th and October 18th 2006. During these periods, mean NO emissions (±S.E., in terms of mass of nitrogen) were 124.0 ± 28.7, 134.6 ± 23.3 (summer sheepfold) and 214.4 ± 79.6 μg NO–N m−2 h−1 (winter sheepfold), respectively, and thus, three magnitudes higher than observed steppe NO emissions in the same region. The NO fluxes were not significantly different between the 2 years, but in summer they were much higher than in spring (p < 0.05). Temperature and moisture of the faeces layer significantly regulated the NO fluxes (p < 0.01). The direct NO emission factor (EF) for faeces and urine excreted in the sheepfolds was 0.7 g NO–Nemitted kg−1 Nexcreted, which was almost 37 times lower than a recently reported N2O EF. We estimated the total NO emission from the sheepfolds of the Baiyinxile livestock farm to be 1.82 ± 0.43 tons NO–N year−1, which accounts to approximately 12.3% of the total NO emission from this steppe region. With the rapid increase of livestock numbers, sheepfold NO emissions may further increase and contribute to high N deposition in confined areas around sheepfolds. 相似文献
376.
Aske Skovmand Bosselmann Klaus Dons Thomas Oberthur Carsten Smith Olsen Anders Ræbild Herman Usma 《Agriculture, ecosystems & environment》2009,129(1-3):253-260
Production of coffee, especially by small holders, is often associated with various forms of shade management. To analyse the effects of shade on physical coffee quality and on sensorial cup quality of Coffea arabica L. cv. Caturra KMC, a study was carried out with 94 plots on 16 farms in two municipalities, Timaná and Oporapa, located at elevations from 1272 to 1730 masl. in Huila, Colombia. The study was designed with emphasis on shade cover variation within each of the two study areas, while minimizing the variability of environment, agronomic management other than shade, and post-harvest processing. 46 samples of shade coffee and 46 samples of sun coffee were evaluated for physical and sensorial attributes using three professional coffee cuppers (assessors). A principal component analysis including all quality and environmental variables showed that sensory attributes were influenced negatively by shade, and that physical attributes were influenced positively by altitude. A mixed linear model, with coffee cupper and farm as random variables, revealed different shade effects on coffee quality in the two areas. In Oporapa, situated at high altitudes, shade had a negative effect on fragrance, acidity, body, sweetness and preference of the beverage, while no effect was found on the physical quality. In Timaná, situated at lower altitudes, shade did not have a significant effect on sensorial attributes, but significantly reduced the number of small beans. At high altitudes with low temperatures and no nutrient or water deficits, shade trees may thus have a partly adverse effect on C. arabica cv. Caturra resulting in reduced sensory quality. The occurrence of berry borer (Hypothenemus hampei) was lower at high altitudes and higher under shade. Future studies on shade and coffee quality should focus on the interaction between physical and chemical characteristics of beans. 相似文献
377.
Kate Arnold Yvonne Pohlner Klaus Zuberbühler 《Behavioral ecology and sociobiology》2008,62(4):549-559
Some non-human primates produce acoustically distinct alarm calls to different predators, such as eagles or leopards. Recipients
respond to these calls as if they have seen the actual predator, which has led to the notion of functionally referential alarm
calls. However, in a previous study with free-ranging putty-nosed monkeys (Cercopithecus nictitans martini), we demonstrated that callers produced two acoustically distinct alarm calls to eagle shrieks and leopard growls, but both
alarm calls were given to both predators. We can think of two basic explanations for this surprising result, a methodological
and theoretical one. Firstly, acoustic predator models may not always be suitable to test alarm call behaviour in primates,
sometimes causing uncharacteristic behaviour. Secondly, referential alarm calling may not be a universal feature of primate
alarm call systems. Considering the methodological and theoretical importance of these possibilities, we conducted a follow-up
study using life-sized leopard, eagle, and human models on the same population and compared the resulting vocal responses
to those given to acoustic predator models. We compared the alarm call series given to each of these predator model types
and found a considerable degree of consistency suggesting that the mode of presentation did not affect anti-predator calling
strategies. However, evidence for audience effects on calling behaviour was inconclusive. While it appears that predator class
is reliably encoded by different call series types irrespective of the mode of presentation, observations of these same call
series given in non-predatory contexts indicate that predator class is unlikely to be the relevant organising principle underlying
the alarm-calling behaviour in this species. We conclude by offering an alternative, non-referential, account of the alarm-calling
system exhibited by this species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
378.
Klaus Peter Rippe 《Journal of Agricultural and Environmental Ethics》2000,12(1):71-80
In the public debate concerning novel foods, someconsumer groups claim a consumer right to have accessto certain kinds of food in the market. To discusssuch statements, the paper identifies the reasons thatmay justify liberal states to regulate food. Althoughit defends certain paternalistic activities, itfavours an autonomy-centred food policy. Autonomy andconsumer sovereignty require that certain conditionsare fulfilled. It may be argued that one suchcondition is that the consumer should have choices.Against this position, the paper defends the view thatliberty rights to choose are limited to areas whichare of great importance for personal identity and thegood life. Local decisions in the area of foodconsumption do not have such importance, though globalones may have it. But even if this were true,government activity to protect such liberties shouldbe limited to the guarantee of formal conditions forthe good life of persons. It is not a legitimate taskof the government to safeguard specific conceptions ofthe good life. 相似文献
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Extent of pyrolysis impacts on fast pyrolysis biochar properties 总被引:2,自引:0,他引:2
Brewer CE Hu YY Schmidt-Rohr K Loynachan TE Laird DA Brown RC 《Journal of environmental quality》2012,41(4):1115-1122
A potential concern about the use of fast pyrolysis rather than slow pyrolysis biochars as soil amendments is that they may contain high levels of bioavailable C due to short particle residence times in the reactors, which could reduce the stability of biochar C and cause nutrient immobilization in soils. To investigate this concern, three corn ( L.) stover fast pyrolysis biochars prepared using different reactor conditions were chemically and physically characterized to determine their extent of pyrolysis. These biochars were also incubated in soil to assess their impact on soil CO emissions, nutrient availability, microorganism population growth, and water retention capacity. Elemental analysis and quantitative solid-state C nuclear magnetic resonance spectroscopy showed variation in O functional groups (associated primarily with carbohydrates) and aromatic C, which could be used to define extent of pyrolysis. A 24-wk incubation performed using a sandy soil amended with 0.5 wt% of corn stover biochar showed a small but significant decrease in soil CO emissions and a decrease in the bacteria:fungi ratios with extent of pyrolysis. Relative to the control soil, biochar-amended soils had small increases in CO emissions and extractable nutrients, but similar microorganism populations, extractable NO levels, and water retention capacities. Corn stover amendments, by contrast, significantly increased soil CO emissions and microbial populations, and reduced extractable NO. These results indicate that C in fast pyrolysis biochar is stable in soil environments and will not appreciably contribute to nutrient immobilization. 相似文献