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Bottom soil samples were collected from 35 ponds in the vicinity of Samutprakarn, Thailand. Ponds ranged in age from 3 to 39 years and had been used continuously for production of tilapia. Liming materials had been applied in large amounts, and bottom soils of all ponds had pH above 7, low exchange acidity, and free carbonate. Pond soils often contained between 1% and 2% total sulphur, suggesting that they were potential acid–sulphate soils. However, acidity from sulphide oxidation was not expressed because carbonate in the soil neutralized it. Concentrations of total carbon seldom exceeded 4% and the average for organic carbon was 1.90%. The correlations between pond age and both total carbon and organic carbon concentration were weak (r=0.34 and 0.36 respectively). Concentrations of nitrogen in bottom soils did not differ with pond age and ranged from 0.1% to 0.3% with an average of 0.19%. The average ratio of concentrations of carbon and nitrogen was 11. Acid‐extractable phosphorus concentrations averaged 217 mg kg?1, but the phosphorus adsorption capacity averaged 768 mg kg?1 suggesting that soils still have considerable reserve capacity to adsorb phosphorus. Ponds can be used annually for semi‐intensive production of tilapia, and presumably other species, for many years without serious deterioration of bottom soil quality. 相似文献
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对采自贵州省册亨县、三都县的窄叶野豌豆野生种进行了引种驯化。结果表明：其产草量中等，鲜草３７．５～４５ｔ／ｈｍ２，草质优良；生育期短，早熟；种子产量高，收纯净种子５００～６００ｋｇ／ｈｍ２。适合在我国南方中亚热带地区同水稻、玉米轮作，也可作为农田填闲作物栽培 相似文献
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不同海拔高度西藏高原牦牛若干血液生理常值的比较 总被引：5，自引：0，他引：5
本试验对西藏藏北高原那曲(海拔4500米)牦牛,藏南河谷林芝(海拔3000米)牦牛进行了某些高原生理特性对比研究。测定了红细胞总数、红细胞压积、血液总量、血红蛋白含量及其电泳分析、血清蛋白含量及其电泳分析等。测定结果表明,生活在高海拔的藏北那曲牦牛,其红细胞总数、红细胞压积、血液总量、血红蛋白均极明显地高于较低海拔的藏南河谷牦牛,而其红细胞容积的立方微米数值较小,红细胞内血红蛋白的平均重量较轻,并发现变异血红蛋白(A_3)。根据本文分析,其主要归因于高海拔、低氧压。雄性牦牛的变异血红蛋白数量高于雄牦牛,差异极显著(P相似文献
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Branimir Jovančićević Mališa Antić Ivona Pavlović Miroslav Vrvić Vladimir Beškoski Alexander Kronimus Jan Schwarzbauer 《Water, air, and soil pollution》2008,190(1-4):299-307
This paper presents transformations of saturated hydrocarbons of petroleum type pollutants during ex situ bioremediation of soil on the pilot heap (halde), during a period of 6 months, within the grounds of Petroleum Refinery Pan?evo (Serbia). Samples for analysis were taken in time intervals of 2 weeks (P1–P12 samples). Organic substance was extracted by Soxhlet’s method and quantified. Isoprenoid aliphatics, in particular pristane and phytane, and polycyclic aliphatics of sterane and triterpane types in saturated hydrocarbon fractions were analysed by GC-MS (SIM method). Significant amounts of n-alkanes have not been detected. The MS-chromatogram revealed only marginal amounts of pristane and phytane in sample P1. Pristane and phytane occurred in sample P8, and in even higher quantities in the final sample P12. The proceeding bioremediation process was accompanied by the decrease of the relative amounts of pentacyclic terpanes of hopane type, compared to tri- and tetracyclic terpanes. In the initial sample P1 the distribution of steranes and hopanes follows a pattern, which is characteristic for crude oils. However, their identification by SIM method was not possible in samples P8 and P12 because of the reduced concentration. The observed changes in the alkane fractions’ compositions may be considered as atypical, referring to the fact that during oil biodegradation under natural conditions, decomposition of isoprenoids occurs much easier and faster than decomposition of polycyclic alkanes of tri-, tetra- and pentacyclic terpane, sterane and diasterane types, after the decomposition of n-alkanes has been almost completed. 相似文献
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Effect of Nitrogen and Sulphur Application on Yield and Fatty acid Composition of Mustard (Brassica juncea L.) Oil 总被引：1，自引：0，他引：1
The effects of nitrogen and sulphur on the yield and fatty acid composition of mustard ( Brassica juncea L.) oil were studied in a field experiment. Significantly higher grain and oil yields were obtained with N and S application. Applications of nitrogen up to 60 kg ha−1 and sulphur up to 40 kg ha−1 favourably influenced the grain yield. Increasing levels of N decreased the oil content while application of sulphur improved the oil content. The contents of linoleic and linolenic acid were maximum (16.82 and 8.73%, respectively) with 60 kg N along with 40 kg S ha−1 . No use of fertilizers led to higher contents of undesirable fatty acids such as palmitic (hypercholesterimic) and erucic (do not have food value) acids. 相似文献
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Mali Hartviksen Anne Marie Bakke José G. Vecino Einar Ringø Åshild Krogdahl 《Fish physiology and biochemistry》2014,40(5):1621-1637
The present study investigated the effect of various alternative diet ingredients partially replacing fishmeal (FM) on digestive and metabolic parameters in Atlantic salmon (Salmo salar L.) post-smolts (initial body mass 305 ± 69 g) following 12 weeks of feeding. Experimental diets containing 20 % extracted sunflower (ESF), pea protein concentrate (PPC), soy protein concentrate (SPC), feather meal (FeM) and poultry by-product (PBY) were compared to a reference diet containing FM as the main protein source. For the different intestinal compartments trypsin, lipase, bile salts, dry matter and chyme-associated leucine aminopeptidase (LAP) were measured from the content and LAP was measured in the tissue. Selected metabolites were measured in plasma samples. In general, use of plant proteins resulted in low C-LAP activity, low plasma cholesterol and high plasma magnesium. The plasma levels of cholesterol and Mg reflecting were most likely reflections of the composition of the diet, while the LAP activity in chyme may indicate lower epithelial cell turnover. Other responses varied depending on the plant protein source. Results from the animal protein substitution also varied both between diets and compartments; however, both materials increased lipase activity in DI. FeM resulted in a significant increase in both total and specific LAP activities suggesting an attempt to increase the digestive capacity in response to low digestibility of the diet while PBY showed very little difference from the FM-fed control fish. The present trial indicates that 20 % PPC, SPC and PBY can partially replace FM in diets for Atlantic salmon. The qualities of ESF and FeM used in this trial show little promise as FM replacement at 20 % inclusion level. 相似文献
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我国丝绸面临的困境及成因浅析 总被引：1，自引：0，他引：1
丝绸业是以茧丝绸为纽带 ,以出口创汇为主的跨越农工贸的外向型行业 ,现在我国的蚕茧和生丝产量分别约占世界总产量的78%和 72 % ,丝类、绸缎和丝绸服饰的出口量分别约占世界贸易的 90 %、50 %和 45% ,1 950～ 1 998年间丝绸出口创汇达 42 2 .1 2亿美元 ,在世界丝绸业和国民经济中占有重要的地位。1 我国丝绸业面临的困境80年代后期 ,我国丝绸行业高速发展 ,产量大幅攀升 ,出口量迅猛增加 ,但至 90年代中期 ,全行业发生前所未有的亏损 ,近来 ,以加入ＷＴＯ为契机 ,行业情况有所好转 ,但也仍在困境中艰难跋涉 ,发展前景不容盲目乐观。自 1 9… 相似文献
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Water, Air, & Soil Pollution - In the present work, rapid test methods for field screening of soil for Cu, Ni, and Pb content are presented. They are based on commercially obtainable Microquant... 相似文献