有机肥料中有机质的检测方法及其注意问题

有机肥料在保持培养区内土地湿润肥沃、提高优质农作物产品的产量水平及安全品质等有着极其重要的作用。判断土壤肥沃程度的主要依据是有机质含量的多少。选取不同来源的土壤有机性肥料,其含有机质数量的检测和方法上也应各不相同,通过采取不同途径的取样方法分别测定并予以比较,从而选择更加合适的方法进行检测。通过分别用灼烧法、NY/T 525—2021法中介绍的重铬酸钾氧化分解法等测定了有机质含量,比较三种不同有机质检测技术方法分别测定得的有机质结果,分析对比了有机质检测主要影响指标因素分析及目前有机配方肥料检测新方法标准中与传统旧测定方法标准之间在实际测量的结果方法上产生的一些差异,并着重阐述讨论了在有机配方肥料生产中在有机质成分的有机检测的过程操作中的需要注意的问题。

宝石级红珊瑚的激光拉曼光谱特征

宝石级红珊瑚是一种重要的有机宝石,其常见的商业品种主要有摩摩珊瑚、阿卡珊瑚和沙丁珊瑚。对这3种常见的宝石级红珊瑚样品进行激光拉曼光谱研究发现,不同的宝石级红珊瑚样品其红色部位均出现1 016,1 128,1 296,1 518,2 147,2 250,2 633,3 032,3 361,3 740 cm-1的成套谱峰。实验结果表明,宝石级红珊瑚样品白芯的拉曼谱图与天然白色珊瑚的相一致;不同商业品种的宝石级红珊瑚样品具有相同特征的有机质成分,认为其颜色的成因与有机质成分有关。

Effect of Reclamation Time and Land Use on Soil Properties in Changjiang River Estuary,China

The objective of this study is to analyze soil physical and chemical properties,soil comprehensive functions and impact factors after different years of reclamation.Based on the survey data taken from 216 soil sampling points in the Fengxian Reclamation Area of the Changjiang (Yangtze) River Estuary,China in April 2009 and remotely sensed TM data in 2006,while by virtue of multivariate analysis of variance (MANOVA),geo-statistical analysis (GA),prin-cipal component analysis (PCA) and canonical correspondence analysis (CCA),it was concluded that:1) With the in-crease in reclamation time,soil moisture,soil salinity,soil electric conductivity and soil particle size tended to decline,yet soil organic matter tended to increase.Soil available phosphorous tended to increase in the early reclamation period,yet it tended to decline after about 49 years of reclamation.Soil nitrate nitrogen,soil ammonia nitrogen and pH changed slightly in different reclamation years.Soil physical and chemical properties reached a steady state after about 30 years of reclamation.2) According to the results of PCA analysis,the weighted value (0.97 in total) that represents soil nutrient factors (soil nitrate nitrogen,soil organic matter,soil available phosphorous,soil ammonia nitrogen,pH and soil particle size) were higher than the weighted value (0.48 in total) of soil limiting factors (soil salinity,soil elec-tric conductivity and soil moisture).The higher the F value is,the better the soil quality is.3) Different land use types play different roles in the soil function maturity process,with farmlands providing the best contribution.4) Soil physi-cal and chemical properties in the reclamation area were mainly influenced by reclamation time,and then by land use types.The correlation (0.1905) of the composite index of soil function (F) with reclamation time was greater than that with land use types (-0.1161).

Influence of Aluminum and Cadmium Stresses on Mineral Nutrition and Root Exudates in Two Barley Cultivars

A hydroponic experiment was carried out to study the effect of aluminum （Al） and cadmium （Cd） on Al and mineral nutrient contents in plants and Al-induced organic acid exudation in two barley varieties with different Al tolerance. Al- sensitive cv. Shang 70-119 had significantly higher Al content and accumulation in plants than Al-tolerant cv. Gebeina, especially in roots, when subjected to low pH （4.0） and Al treatments （100 μmol L^-1 Al and 100 μmol L^-1 Al ＋1.0 μmol L^-1 Cd）. Cd addition increased Al content in plants exposed to Al stress. Both low pH and Al treatments caused marked reduction in Ca and Mg contents in all plant parts, P and K contents in the shoots and leaves, Fe, Zn and Mo contents in the leaves, Zn and B contents in the shoots, and Mn contents both in the roots and leaves. Moreover, changes in nutrient concentrations were greater in the plants exposed to both Al and Cd than in those exposed only to Al treatment. A dramatic enhancement of malate, citrate, and succinate was found in the plants exposed to 100 μmol L^-1 Al relative to the control, and the Al-tolerant cultivar had a considerable higher exudation of these organic acids than the Al-sensitive one, indicating that Al-induced enhancement of these organic acids is very likely to be associated with Al tolerance.

Relative Frequencies, Chemical Composition and in vitro Organic Matter Digestibility of Forage Consumed by Sheep in Humid Tropic of West Africa

The experiment was conducted during the short dry and the short rainy seasons in 2008. A botanical inventory and relative frequencies of forage selected by Djallonke sheep grazing were developed by observation and hand-plucking. Chemical composition and in vitro organic matter digestibility （IVOMD） of hand-plucked material was determined. From July to October, woody plants are a major component of the sheep diet. Sheep selected 40 woody plants and 21 species of herbaceous. During the dry season, grazing occurred more frequently in the fallows. The most frequent woody species belonged to Elaeis guineensis and Fagara zanthoxyloides. At the rainy season, a high proportion of Panicum maximum and Eleucine indica were sampled. Crude protein was high in woody leaves at the dry season. Crude fibre were more variable in herbaceous than in woody and herbaceous were generally higher in the levels of fibre. Chromolaena odorata, Citrus sinensis, Vitex doniana were very high in IVOMD. Spondias mombin, Moringa oleifera, Persea americana, Psidium guajava, Dialium guineense presented lowest values in IVOMD. Among herbaceous, Andropogon gayanus and Panicum maximum still presented a high value of IVOMD at the dry season. High proteins suggest woody with potential as nitrogen supplements to ruminants fed low quality forage during the dry season.

Decomposition of algal lipids in clay-enriched marine sediment under oxic and anoxic conditions

A series of laboratory incubation experiments were conducted to examine the decomposition of algal organic matter in clay-enriched marine sediment under oxic and anoxic conditions. During the 245-day incubation period, changes in the concentrations of TOC, major algal fatty acid components （14：0, 16：0, 16：1, 18：1 and 20：5）, and n-alkanes （C16-C23） were quantified in the samples. Our results indicate that the organic matters were degraded more rapidly in oxic than anoxic conditions. Adsorption of fatty acids onto clay minerals was a rapid and reversible process. Using a simple G model, we calculated the decomposition rate constants for TOC, n-alkanes and fatty acids which ranged from 0.017-0.024 d^-1, 0.049-0.103 d^-1 and 0.011 to 0.069 d-l, respectively. Algal organic matter degraded in two stages characterized by a fast and a slow degradation processes. The addition of clay minerals montmorillonite and kaolinite to the sediments showed significant influence affecting the decomposition processes of algal TOC and fatty acids by adsorption and incorporation of the compounds with clay particles. Adsorption/association of fatty acids by clay minerals was rapid but appeared to be a slow reversible process. In addition to the sediment redox and clay influence, the structure of the compounds also played important roles in affecting their degradation dynamic in sediments.

Geochemistry of solvable organic matter from source rocks in Shangkuli Formation of Labudalin Basin

A suit of lacustrine source rocks are developed in volcanic deposits in the Shangkuli Formation of the Cretaceous. However, it is poor to understand the characteristics of source rocks due to the low degree of exploration, thus the exploration is severely constrained in this area. Based on the geochemical analysis, the analytic technique of GC and GC-MS, combined with the characteristics of solvable organic matter and biomarkers of the source rocks, the authors discussed the depositional environment, the derivation of the matrix and the maturity characteristics of the organic material of the Shangkuli Formation in Cretaceous. The results show that the organic matter mainly belongs to type Ⅱ1 kerogen, whose abundance is relatively high; it was formed in reductive surrounding where was deep-lake; the hydrocarbon is characterized by mixed-source of organic matter. The thermal evolution of source rocks had reached maturation stage.

Comparison of volatile constituents in two types of mugwort leaves(produced in Qichun and Nanyang) using the headspace GC-MS

Objective： To compare the volatile constituents in mugwort leaves produced in Qichun, Hubei Province and Nanyang, Henan Province. Methods： The volatile constituents were extracted using headspace heating and analyzed using gas chromatography-mass spectrometry （GC-MS）. Then a qualitative analysis was made according to the standard database provided by the National Institute of Standards and Technology （NIST） and the relative contents of each constituent were calculated using the peak area normalization method. Results： A total of 59 compounds were identified from the mugwort leaves from Qichun and 51 compounds were identified from the mugwort leaves from Nanyang. These mainly include monoterpenoids, sesquiterpenoids, C^HvOz and other compounds involving the aldehyde, ketone, alkane and benzene. The mugwort leaves from Qichun and Nanyang share 32 common volatile constituents. The chromatographic peak area of identified compounds accounting for 96.38% of GC-MS total chromatographic peak areain Qichun mugwort leaves, versus 95.54% of that in Nanyang mugwort leaves. Conclusion： The headspace heating extraction combined with GC-MS technology can evidently display similarities and differences of volatile constituents in mugwort leaves produced in different areas and thus provide scientific basis for the quality and screening of mugwort leaves.