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1.
D. W. Bussink 《Nutrient Cycling in Agroecosystems》1994,38(2):111-121
Grazed pastures emit ammonia (NH3) into the atmosphere; the size of the NH3 loss appears to be related to nitrogen (N) application rate.The micrometeorological mass balance method was used to measure NH3 volatilization from rotationally grazed swards on three plots in the autumn of 1989 and throughout the 1990 growing season. The aim of the research was to derive a mathematical relationship between NH3 volatilization and N application rate, which would vary between soil type and weather conditions. In both years the plots received a total of 250, 400 or 550 kg N ha–1 as calcium ammonium nitrate (CAN) split over 6 to 8 dressings. The number of grazing cycles ranged from 7 to 9 for the three N plots.In the last two grazing cycles of 1989, NH3 losses were 3.8, 12.0 and 14.7 kg N ha–1 for the 250N, 400N and 550N plots, which was equivalent to 5.3%, 13.9% and 14.4% of the amount of N excreted on the sward, respectively. In 1990, NH3 losses were 9.1, 27.0 and 32.8 kg N ha–1 for the 250N, 400N and 550N plots, which was equivalent to 3.3%, 6.9% and 6.9% of the N excreted, respectively. Differences in urine composition between the plots were relatively small. Rainfall and sward management affected the size of the NH3 volatilization rate. Volatilization of NH3 was related to N excretion and N application rate.A calculation procedure is given to enable the estimation of NH3 volatilization from N application rate. Adjustments can be made for grazing efficiency, grazing selectivity, N retention in milk and liveweight gain, concentrate N intake and milking duration. Losses of NH3 increase progressively with an increase in N application rate until herbage yield reaches a maximum at an application rate of about 500 kg N ha–1 yr–1. 相似文献
2.
Michal Apollo 《The International journal of environmental studies》2017,74(1):129-158
Each year, millions of mountaineers visit high-mountain areas. They generate tonnes of faeces and cubic hectometres of urine annually. Thus, proper disposal of human waste is important for the conservation and appropriate management of high-mountain areas. The management can address the issue in three ways: the good (complete/non-invasive); the bad (partial/superficial); and the ugly (invasive). With use of those categories, 20 selected summits from different parts of the world have been evaluated, separately in respect to faeces and urine. It was expected that correct or incorrect disposal of human waste would depend on the changing altitude and/or development level. Disappointingly, the correlation between selection criteria (better or worse solution) and the increase of altitude does not exist. Similarly, the increase of the development level does not play a significant role, especially when urine is taken under consideration. The problem is more global than was thought. The paper makes recommendations which could lead to reduction of this problem. 相似文献
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以分离自母乳婴儿源的乳杆菌——鼠李糖乳杆菌BF-1、植物乳杆菌BF-15、唾液乳杆菌BF-29、干酪乳杆菌BF-55为对象,研究这些菌株对体外模拟人工胃、肠液及胆盐的耐受性,对Caco-2细胞的黏附能力、安全性和对小鼠脾淋巴细胞增殖活性的影响,探讨菌株的免疫调节活性。试验结果表明:植物乳杆菌BF-15对人工消化液和胆盐有较强的耐受性,对Caco-2细胞黏附能力[(7.10±0.30)CFU/cell]显著高于阳性对照菌株LGG[(3.90±0.30)CFU/cell](P<0.05);BF-15除对氨基糖苷类、糖肽类抗生素的固有耐药性外,对苯唑西林、头孢噻吩也有耐药性,无抗性质粒;BF-15和LGG的活性和热致死菌在一定的菌浓范围(1×10^6~10^7CFU/mL)均促进体外小鼠淋巴细胞增殖,表现出剂量依赖关系,同时活性菌株作用效果明显优于热致死菌株。在相同菌浓条件下,两株菌体外免疫调节能力没有显著性差异(P>0.05)。母乳婴儿源乳杆菌——植物乳杆菌BF-15具有较强的抗逆性,较高的黏附性和一定的免疫调节能力。 相似文献
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Zicarelli F Calabrò S Cutrignelli MI Infascelli F Tudisco R Bovera F Piccolo V 《Journal of the science of food and agriculture》2011,91(7):1213-1221
BACKGROUND: The aim of this trial was to evaluate the replacement of rumen fluid with faeces as inoculum in studying the in vitro fermentation characteristics of diets for ruminants using the in vitro gas production technique. Six iso‐protein diets with different forage/concentrate ratios were incubated with rumen fluid (RI) or faeces (FI) collected from sheep. RESULTS: Most of the fermentation parameters were influenced by diet and inoculum (P < 0.01). With both inocula, organic matter degradability (dOM), cumulative gas production (OMCV) and maximum fermentation rate (Rmax) increased as the amount of concentrate in the diet increased. Rmax was lower with FI vs RI (P < 0.01); dOM was higher with FI vs RI and the diet × inoculum interaction was significant. As expected, with both inocula, Rmax increased as the neutral detergent fibre content of the diet decreased. Significant correlations were obtained using both inocula between OMCV/dOM and gas/volatile fatty acid (VFA), while the correlation VFA/dOM was significant only with FI. The microbial biomass yield calculated by stoichiometric analysis for all diets was higher with FI vs RI. With FI the organic matter used for microbial growth showed an overall decreasing trend as the amount of concentrate in the diet increased. CONCLUSION: The results indicate that both faeces and rumen fluid from sheep have the potential to be used as inoculum for the in vitro gas production technique. Copyright © 2011 Society of Chemical Industry 相似文献
6.
Laur A. Bravo Eva. Maas Fulgencio Saura-Calixto 《Journal of the science of food and agriculture》1993,63(1):63-68
The possible degradation of non-extractable condensed tannins (NECT) within the intestinal tract and their effect on faecal weight and composition was studied. Two groups of male Wistar rats were fed either a NECT-free control diet, or a diet containing 100 g carob pod concentrate kg?1 (53 g NECT kg?1 dry matter) for 5 weeks. A slight effect of NECT on growth rate was observed in the fifth week. The NECT diet did not affect food intake. Significant increases of total faecal output as well as water, nitrogen and fat excretion were observed. NECT were not degraded in the intestinal tract, since they were quantitatively recovered in faeces (98 ± 1%). Since the usual spectrophotometric methods gave contradictory results on NECT levels in the diet and faeces, an alternative method based on Klason lignin residues was used. 相似文献
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D. W. Bussink 《Nutrient Cycling in Agroecosystems》1992,33(3):257-265
The micrometeorological mass balance method was used to measure ammonia (NH3) volatilization from rotationally grazed swards throughout the 1987 and 1988 growing seasons. In both years the swards were dressed with calcium ammonium nitrate (CAN) split over 7 dressings. In 1987 the sward received a total of 550 kg N ha–1, in 1988 a total of 550 or 250 kg N ha–1. For the 550 kg N ha–1 treatments there were 8 and 9 grazing cycles, respectively, in 1987 and 1988 and 7 for the 250 kg N ha–1 treatment. Losses from the 550 N sward were 42.2 and 39.2 kg N ha–1 in 1987 and 1988, respectively; this was equivalent to 8.5 and 7.7% of the N returned to the sward in the excreta of the grazing cattle. The NH3 loss from the 250N sward was 8.1 kg N ha–1 in 1988, which was equivalent to 3.1% of the N returned to the sward in excreta during the growing season. There was a wide variation in NH3 volatilization between the individual grazing periods. This indicates the necessity of continued measurements throughout the growing season to obtain reliable data on NH3 volatilization. Soil humidity is suggested to be a key factor, because emissions were high from wet soil, and low from drier soil. Results of a Monte Carlo simulation study showed that the measured NH3 loss from the 250 and 550 N swards had a standard deviation of 13 and 5% of the mean, respectively. 相似文献
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Sven Steiner Johannes L.M. Steidle Joachim Ruther 《Journal of Stored Products Research》2007,43(4):587-593
Males and females of the parasitic wasp Lariophagus distinguendus respond to volatiles emitted by the larval faeces of one of their hosts, the granary weevil Sitophilus granarius. Previous studies have shown that attractive chemicals are emitted by astigmatid mites living in the host faeces and that these cues are attractive only to experienced parasitoids. In the present study we demonstrate that larval faeces of the host and headspace extracts of the faeces are attractive for both sexes of the parasitoid even when the mites were experimentally excluded from the beetle rearings. The response to volatiles from mite-free host faeces is innate. In order to elucidate the chemistry of this odor, headspace extracts were fractionated by adsorption chromatography. Tests using combinations of fractions of different polarities revealed that both the non-polar pentane and the polar methanol fractions were necessary to maintain the attractiveness. This indicates that the attractive odor is composed of a complex blend of components with different polarities. The composition of the polar fraction was analyzed by gas chromatography-mass spectrometry, whereas elucidation of the structure of non-polar components has not been possible so far. By orientating toward the same host-related volatiles used by females for host finding, L. distinguendus males may be arrested in patches of potentially high female density and thus increase their chance of mating. 相似文献
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Kuroki M Phichaichumpon C Yasuoka A Chiranairadul P Chosa T Sirinirund P Miyazaki T Kakeya H Higashiyama Y Miyazaki Y Ishida Y Kohno S 《Yeast (Chichester, England)》2004,21(10):809-812
We successfully isolated Cryptococcus neoformans from chicken faeces in suburban areas of Thailand. C. neoformans was isolated from 36/150 houses (24.0%) in the dry season and 6/150 (4.0%) in the rainy season. All environmental isolates were of serotype A. The high isolation rate of 24% from chicken faeces has never been reported previously. Our environmental study could probably explain the high incidence of cryptococcal meningitis in HIV patients in Thailand. 相似文献
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以蚕沙为原料,采用直接皂化法制备叶绿素铁钠盐,通过单因素实验和正交试验设计研究了体系pH值、超声时间、超声温度、置铁量、置铁时间、置铁温度对叶绿素铁钠盐产率的影响,其最优工艺条件为:10g干蚕沙粉先在pH≈12的体系中,80℃下超声120min;再于pH≈2~3的体系中,65℃下酸化30min,加入6mL10%FeSO4溶液,置铁时间150min,最后用10%NaOH-CH3CH2OH调节溶液使叶绿素铁酸成盐析出.通过对照实验,直接皂化法叶绿素铁钠盐的得率大于传统制备法叶绿素铁钠盐的得率,而且直接皂化法比传统制备法在制备工艺上还少一道工序,因此直接皂化法是可行的. 相似文献