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The mono-, di-, tri-, tetra-, penta-, and hexaphosphates of inositpl accounted for between 11·2 and 30·4 per cent of the organic P in three English and four Nigerian soils. M yoinositol hexaphosphate was the component present in greatest amount in all soils. The lower esters (mono-, di-, and triphosphates) accounted for less than 3 per cent of the organic P in all soils, with the lowest amounts in the soils from Nigeria. For the penta- and hexaphosphates the ratio of myo- plus dl- isomers to scyll oinositol varied from 2·9 to over 10, the highest ratio occurring in the soils from Nigeria. Examination of the techniques showed that they gave approximately correct estimates of the inositol phosphates. The organic P in soil which was not estimated as inositol phosphate occurred in other forms. 相似文献
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The combined amounts of inositol penta- and hexaphosphates in a number of Canadian soils of differing origin have been measured. The esters were precipitated as barium salts from alkali extracts and purified by anion-exchange chromatography; their identity was confirmed by paper-partition chromatography. An alternative method involving precipitation of the esters as ferric salts in acid medium was found to give much lower values, probably because of incomplete precipitation. Values for eighteen surface soils ranged from 20 to 71 and for twelve subsoils from 18 to 43 ppm P. The amounts found were related to the contents of both total phosphate and total organic phosphate, and accounted, on average, for 6 per cent of the former and 17 per cent of the latter. A correlation of +0.67 (P < 0.01) was found with orthophosphate retention capacity but correlations with soil N and C contents were poor. Amounts of the esters were higher in forest soils than in grassland soils. 相似文献
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A calcareous organic soil was extracted by shaking with Na+-resin suspended in 0·2M acetyl acetone at pH 8·3. Fractionation of the fulvic acid on Sephadex G 25 gave (a) a high molecular-weight component which contained inositol tetraand hexa-phosphates and a sugar phosphate; (b) low molecular-weight components which included the mono-, di-, and triphosphate esters of inositol and two sugar phosphates, but no free inositol phosphates. Inositol phosphates and sugar phosphates accounted for 30·2 per cent and 16·6 per cent of the soil organic P respectively. Our evidence indicates that these phosphate esters exist in an organic complex. 相似文献
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T. R. MOORE 《European Journal of Soil Science》1973,24(2):162-171
Twenty-four soils from north-east Scotland have been subjected to differential extraction techniques to determine the effect of hydromorphism on various Fe, Mn, and A1 fractions. There were pronounced losses of dithionite-extractable Fe and Mn from gleyed horizons, but the 'silicate-Fe’fraction appeared to be relatively unaffected. The oxalate-extractable Fe and A1 fractions also decreased in response to gleying. The ratio of the oxalate- to dithionite-extractable Fe fractions (Fe0/Fed) increased in gleyed horizons, presumably due to variations in the rate of ageing and crystallization of amorphous Fe oxides and hydroxides. 相似文献
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我国菜园土壤中某些重金属元素的含量与分布 总被引:132,自引:2,他引:132
本文对我国各主要起源母土上发育的厚熟土、不同熟化程度的菜园土以及相对应的粮田土壤37个剖面中某些重金属元素的全量及有效态含量进行了研究,结果表明:菜园土壤随种菜历史的延长、熟化程度的增加、重金属元素Zn、Cu、Pb的含量有明显增高的趋势。元素在剖面中的分布以表层含量最高,向下递减。厚熟土由于具有较厚的熟化表层,元素全量及有效态含量在0-40cm土层中均较高,多在过渡层之下出现突然降低的转折;中度和 相似文献
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Total amounts of Mn, Fe, Ni, Cu, Zn, As, Bt, Rb, Si, Y, Zr and Pb were determined in soil samples from approximately 250 profiles. Examples of automatically plotted maps show the distribution of some of these elements in topsoils and subsoils. Element distribution in the soils is related to land units based on underlying rock-type and air photograph interpretation; these units distinguish soils of different lithological and drainage status and many are dominated by a single soil subgroup. Agricultural and pollution aspects of the work are discussed. The survey indicates the present levels of the elements, and may be used as a comparison in future pollution studies. 相似文献
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西藏土壤中硒的含量及分布 总被引:20,自引:1,他引:20
西藏与地球南北极相似,其生态环境基本保持着原生状态,是地球上至今受人类活动影响和污染最少的地区之一。所以,西藏是进行环境本底调查和表生地球化学研究最为理想的场所。西藏土壤中硒的含量数据,不但对进一步研究西藏高原表生环境中硒的地球化学特征,在这一地区探讨硒与克 山病的关系,防治与硒有关的地方疾病具有重要意义,而且还可以为这一地区环境监测与评价等提供基础信息和依据,也可以成为全国乃至全世界土壤硒环境背景的永久性参比资料。 相似文献
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以大巴山区典型早古生代地层上发育的自然土壤为对象 ,研究了大巴山区土壤中Se、F等生命元素的含量及分布规律。结果表明 :大巴山区土壤中硒、氟的平均含量分别为 6 65± 14 2 5μgg- 1和 670±451μgg- 1,远高于对照和中国土壤背景值 ;富Zn贫Fe的土壤环境有利于Se、F的富集 ;土壤中硒、氟的含量受地层分布、母岩岩性等因素的控制 ,同时 ,表生地球化学作用、生物作用以及山地剥蚀地貌也影响它们在土壤中的重新分配。 相似文献
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土壤氮素矿化的温度水分效应 总被引:38,自引:3,他引:38
应用一级反应动力学模型分析了不同温度、水分条件下间歇淋洗和分次提取通气培养法生成的累积净矿化氮与时间的关系。结果表明,温度对土壤氮素矿化速率常数有明显影响。间歇淋洗加砂培养的回归式为:1ogK=6.80-2497/T;不加砂培养为:1ogK=4.19-1817/T;分次提取培养为:logK=6.47-2937/T。矿化速率常数与水分含量符合直线关系,矿化氮量随水分含量的升高而增加。温度、水分对矿化速度有明显的正交互作用。 相似文献
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贵州省土壤含硒量及其分布 总被引:14,自引:0,他引:14
贵州省土壤全硒含量的范围为0.064-1.326mg/kg,平均值0.369mg/kg。全境土壤含硒有由北向东南和随地势下降而逐步增加的趋势。全省可划分为:1.低硒区2.中低硒区3.中硒区4.中高硒区。贵州多数地区土壤属中等含硒水平,少数土壤富硒,同时还有少量缺硒土壤分布。 相似文献