提高肥料利用率化工部门能做些什么？

介绍了中国肥料利用率状况、所施肥料的去向及土壤中养分的积累与亏损。据估计,中国自１９８５～１９９６年,约有９９００万吨Ｎ被淋失和逸散,６０００万吨Ｐ２Ｏ５和１４００万吨Ｋ２Ｏ固定于土壤中。如何提高肥料利用率是中国化学肥料工业紧迫的课题,针对不同类型化肥厂提出了生产控制释放肥料、腐植酸螯合尿素、稳定的碳酸氢铵、部分酸化磷矿复合肥料、完全水溶性复合肥料以及熔融钾镁肥的途径,以提高肥料利用率。     

不同施肥措施对植烟土壤生物学特性和速效养分的影响

通过两年盆栽试验,研究增施不同有机物料对植烟土壤生物学特性和速效养分的影响。结果表明,与纯施化肥相比,增施芝麻饼肥显著增加土壤碱解氮和速效磷含量,增施生物炭显著增加速效钾含量;增施腐熟秸秆土壤蔗糖酶活性显著提升12%,芝麻饼肥和生物炭处理脲酶活性均显著增加19%,生物炭处理过氧化氢酶活性显著增加27%。增施腐熟秸秆土壤微生物生物量碳最高,达到234.52 mg/kg,生物炭处理土壤微生物生物量氮最高,达到35.29 mg/kg。细菌为植烟土壤可培养菌中的优势菌,增施生物炭显著提升可培养细菌数量,增施腐熟秸秆显著提升可培养真菌和放线菌数量。总体来看,增施不同有机物料能改善土壤生物学特性,增加速效养分含量,从而改善植烟土壤质量。     

Controlling soil water content in fertiliser dissolution experiments

Phosphorus lost in runoff from agricultural land leads to the enrichment of surface waters and contributes to algal blooms. Fertilisers are one source of this P. To compare the water available P of different fertiliser formulations in the laboratory it is necessary to control environmental conditions, temperature, relative humidity and soil water content, prior to simulating rainfall. Two chambers were designed in which relative humidity and soil water content were controlled using salt solutions. An initial design comprising a sealed chamber with three layers of soil samples over a salt bath was found to be inferior to a single layer design. The changes in water content of soil samples were used to test the single layer chamber in a constant temperature environment (15 °C) using a saturated KCl solution (90% relative humidity). Based on the final soil water content of the samples, the spatial variation within the chamber was within tolerable limits. The single layer chamber was used for a simulation experiment comparing the water available P of two commercial fertilisers. Using a saturated resorcinol solution (95% relative humidity) soil samples were equilibrated at 15 °C for 21 days, fertiliser added, and the water available P measured up to 600 h after fertiliser application. The results indicate that the amount of water available P was related to the fertiliser compound and exponentially related to the time since fertiliser application. It was concluded that the single layer chamber is suitable for controlling relative humidity and soil water content in trials such as these where the water available P of fertilisers are being compared.     

食物营养对运动员身体形态的影响研究

目的建立食物营养与运动员营养生化指标和身体形态之间的对应关系,探讨饮食模式可能对运动员身体机能的影响。方法以166名国家注册运动员为研究对象,采用SIMCA-P13+构建运动员饮食模式的OPLS-DA模型,并采用SPSS17.0统计分析软件对调研结果进行分析。结果总能量和脂肪、蛋白质和碳水化合物摄入分别对体脂百分数、体脂含量和体重指数成正相关的影响;微量元素的摄入会影响体脂百分数、增加体脂含量和体重指数;除缬氨酸、苏氨酸、蛋氨酸+胱氨酸外,组氨酸、异亮氨酸、亮氨酸和赖氨酸对运动员身体形态的影响都相似,即异亮氨酸、亮氨酸和赖氨酸的摄入会降低体脂百分数,但是都会增加体脂含量和体重指数;而组氨酸的摄入则会同时降低体脂百分数、体脂含量和体重指数。谷类及相关制品、高糖淀粉类、含糖饮料类和蔬菜类的摄入而增加体脂百分数、体脂含量和体重指数;高糖淀粉类和水果类的摄入而增加体脂百分数、体脂含量,并降低体重指数;畜肉类、禽肉类和蛋类的摄入而减小体脂百分数、体脂含量,并增加体重指数;水产类、豆类和奶类的摄入会减小体脂百分数,并体重指数。结论优秀运动员具有自身相对稳定的饮食模式表现出个体差异性;营养摄入模式不同表现出对运动员的身体机能指标有一定的关联,通过模型识别技术表明营养摄入对运动员身体形态有重要的影响,可通过食物营养与运动员营养生化指标和身体形态之间的对应关系加以控制。     

我国地方绵羊品种与进口羊腿肉的营养质构差异分析

目的分析对比我国不同产区主要地方品种与进口羊腿肉的营养品质与质构差异。方法选取中东部农牧交错带肉羊优势区域主要产区:内蒙古锡林郭勒;西北肉羊优势区域的代表产区:新疆、甘肃和宁夏,以乌珠穆沁羊、滩羊、哈萨克羊3个地方品种为主,同时对比来自澳大利亚和新西兰的进口羊腿,品种分别为澳洲白与无角陶赛特羊。分析羊腿的蛋白、脂肪、脂肪酸及氨基酸、维生素、矿物质含量,以及质构参数。结果澳大利亚羊腿蛋白含量较高;甘肃肃北哈萨克羊脂肪酸组成最优;内蒙古锡林郭勒阿巴嘎旗乌珠穆沁羊的钙、磷、钾含量均较高。结论营养成分受品种、饲养方式、地理环境等综合影响:蛋白含量与品种有关,放牧会增加羊腿中不饱和脂肪酸的含量,地理环境与饲料共同影响羊腿的矿质元素含量特征;口感受饲养方式影响较大,放牧会导致羊肉硬度较高。     

Advection,growth and nutrient status of phytoplankton populations in the lower River Murray,South Australia

To investigate the link between river flow, nutrient availability and development of algal blooms, growth rates of the major phytoplankton species were examined in situ in the lower River Murray, South Australia over the 1994/1995 summer. Eight sites were selected over a 54 km reach between Lock 1 and Nildottie and growth rates estimated by monitoring mean cell density in time‐aligned parcels of water as they travelled downstream. Discharge at Lock 1 during the period of study (3000–5000 ML day⁻¹) typified summer entitlement flows to South Australia. A large, shallow floodplain lake (lagoon), with an hydraulic connection to the river, supported a large population of cyanobacteria in summer, but inputs to the main channel did not substantially affect the abundance and composition of river phytoplankton. Mean net growth rates of Anabaena circinalis and A. flos‐aquae f. flos‐aquae were 0.132 and 0.176 day⁻¹, respectively, although individual rates varied from positive to negative. In contrast, the mean growth rate of the filamentous diatom Aulacoseira granulata was −0.15 day⁻¹, reflecting a decrease in population size with advection downstream. Mean cell densities of the three species did not exceed 5000 cells mL⁻¹ throughout the study. Growth bioassays conducted in the laboratory indicated that nitrogen was often the nutrient limiting algal growth, although it was not established whether nitrogen was limiting in situ. A conceptual model is presented, linking these findings with those of other work on the lower River Murray, to summarize the physical and chemical environmental factors governing the abundance of cyanobacteria in this reach of the river. Copyright © 2000 John Wiley & Sons, Ltd.     

Predicting phytoplankton composition in the River Thames,England

Phytoplankton were sampled fortnightly in summer and monthly in winter for 33 months to determine temporal and spatial variations in taxonomic structure and relate these to the physical and chemical environment. Using canonical correspondence analysis, environmental variables selected by stepwise regression were found to be correlated with the major variable(s) determining phytoplankton composition. An improved proportion of explained variance was achieved by classifying data into three seasonal subsets. The highest percentage of explained variance in phytoplankton composition was achieved for the months March to May (36·5%), the lowest variance explained was for the period June to September (28·6%). Within each season, general linear modelling was used to predict taxa responses to variations in particular environmental variables. Taxa responses to discharge are presented as examples for determining river management policies. The rationale of conceptual models and the empirical models used for this study are discussed. © 1997 John Wiley & Sons, Ltd.     

Genetic and environmental variability in starch,fatty acids and mineral nutrients composition in cowpea (Vigna unguiculata (L) Walp)

Fifteen cowpea cultivars grown in three locations (Kano (12°00′N 8°31′E), Mokwa (9°17′N 5°04′E) and Ago-Iwoye (6°58′N 4°00′)) between 1993 and 1994 were analysed for genotype, environmental and genotype×environment variability for starch (g kg⁻¹), fatty acids (% of total oil) and mineral nutrients (g kg⁻¹) composition. There were significant environmental as well as genetic effects on these nutritional qualities. The environmental effect accounted largely for the variability observed in starch (60%), palmitic acid (80%), arachidic acid (100%), potassium (100%), phosphorus (81%) and manganese (86%), while the genotypic effect accounted largely for the variability observed in linoleic acid (50%), linolenic acid (50%) and copper (68%) contents. Correlation coefficient (pooled data) from the three locations indicated that starch was positively correlated to palmitic acid (r = 0·21, 0·01< P < 0·05), potassium (r = 0·80, P < 0·001) and phosphorus (r = 0·65, P < 0·001), but negatively correlated to oleic (r = −0·23, 0·01< P < 0·05), linoleic (r = −0·67, P < 0·001) and linolenic acid (r = −0·74, P < 0·001) contents. Starch showed a strong positive correlation with magnesium content (r = 0·75) and a strong negative correlation with copper (r = −0·73) and iron (r = −0·62) at the genetic level. This research established the degree of variability for these characters in cowpea. © 1998 Society of Chemical Industry.     

液相循环水热法污泥减量及资源化利用

为攻克目前污泥水热产物价值相对较低、水热液过剩等问题,提出将水热液作为水热介质多次循环利用的工艺方案。通过分析污泥中氮、磷及有机质等重要资源在水热固、液相中的转化及分配规律,探究水热液循环利用在提高污泥水热产物价值、节约水资源方面的可行性和潜在优势。结果表明：水热液循环利用促进液相产物中氮、磷成分积累,在250℃水热条件下,3次循环后液相氨氮质量浓度高达17 000 mg/L,液相总磷质量浓度为200 mg/L,分别是一次水热结果的4倍和5倍,显著提升水热液的资源回收效率;水热液循环利用促进水热固相的成炭过程,有助于提高污泥水热炭化产物的利用价值。通过调控水热反应强度、增加水热液循环次数,可实现水热产物价值最大化,同时提升水资源利用效率。研究结果可为水热法实现市政污泥高效减量化、资源化利用提供理论和技术支撑。     

武陵山地植烟土壤养分和酸度垂直分布特征

为了解种植烤烟对武陵山地土壤养分和酸度垂直变化的影响,采集了湘西烟区不同土壤类型和种植方式的典型剖面土壤,分析了植烟土壤养分和酸度参数的垂直分布特征。结果表明,土壤养分和缓冲容量随土壤深度增加而减少。随土壤剖面深度增加,黄棕壤的pH变化较小,紫色土和黄红壤pH增加,黄壤pH先增加后减少再增加;黄棕壤和黄壤的潜性酸变化较小,黄红壤的潜性酸呈下降趋势,紫色土的潜性酸呈跳跃式变化;黄棕壤、紫色土和黄红壤的阳离子交换量、交换性盐基总量、盐基饱和度以底层相对较高,黄壤以表层相对较高。表层土壤的酸度参数变异大;紫色土和黄红壤的表层土壤交换性酸、交换性氢和交换性铝极显著高于黄棕壤和黄壤;表层土壤交换性盐基总量和阳离子交换量以黄壤相对较高,土壤盐基饱和度以黄棕壤和黄壤相对较高。酸碱缓冲容量按大小排序为黄红壤 > 黄壤 > 黄棕壤 > 紫色土。长期种植烤烟会导致植烟土壤养分表聚化和酸化,水旱轮作和施用石灰、种植绿肥具有改善酸化土壤的作用。