Vertical distribution and bioavailability of 137Cs in organic and mineral soils

The vertical distribution and bioavailability of ¹³⁷Cs in Histosols and mineral soils with different physicochemical properties from the southeast of Bavaria (Germany) more than ten years after the Chernobyl accident were the focus of this study. The vertical distribution of ¹³⁷Cs was low in the investigated soils. About 85–98 % of the total ¹³⁷Cs was located in the upper 10 cm of the mineral soils. Slightly higher ¹³⁷Cs percentages were observed in deeper soil layers of the peat soils. Although the organic matter is assumed to enhance ¹³⁷Cs mobility in soils, ¹³⁷Cs was also located in the upper 10 cm of the peat soils (73–85 %). The highest ¹³⁷Cs‐activities were found in the humus layers of forest soils, where 45–93 % of the total ¹³⁷Cs soil inventories were observed. To determine the bioavailability of radiocesium, the soil‐to‐plant transfer of ¹³⁷Cs and additionally added ¹³⁴Cs was investigated under controlled conditions. The results revealed that the ^134+137Cs soil‐to‐plant transfer factors as well as the percentages of NH₄‐exchangeable ^134+137Cs were much higher for the peat soils and humus layers than for the mineral soils. Nevertheless, the migration of ¹³⁷Cs from the humus layers to the underlying soils was low. Considering the high bioavailability and low migration of radiocesium in the humus layers, it is suggested that radiocesium is involved in a shortcut element cycle in the system humus layer‐plant uptake‐litter. Furthermore, the organic matter has to be taken into account for radiocesium immobilization.     

137Cs在耕作土壤中的均一性分布研究

选择一块面积为35m×30m较为平坦的农耕地作为研究对象,采集68个样点,共计112个样品,对~(137)Cs在土壤中的垂直分布和水平分布进行了探讨.结果表明,~(137)Cs在耕作土壤剖面中分布主要集中在耕层以内,且各个层的质量活度介于2.92～4.01Bq/kg之间,在土壤表层中水平面上质量活度介于28.77～30.98Bq/kg之间,该核素在土壤剖面和地表水平面上都呈现均一性分布特征.     

A growth chamber study of the effect of soil concentration and plant age on the uptake of Sr and Cs by tumbleweed

Abstract

Concentration ratios (CR values) for cesium and strontium were measured in tumbleweed shoots as a function of plant age and radionuclide concentration in a totally mixed soil and radionuclide system. At a given plant age, CR values were found to be independent of soil concentration over five orders of magnitude for Sr and three orders of magnitude for Cs. CR values for Sr in 4‐, 8‐, and 12‐week old plants were 10.8, 9.6, and 19, and for Cs were 0.025, 0.033, and 0.053, respectively. Based on shoot growth and tissue concentration data for Sr and Cs, the CR values appear to be dependent on shoot dry matter production, with the rate of uptake of Sr and Cs remaining relatively constant over the 12‐week period.     

营养型土壤改良剂对酸性土壤中钾的调节及玉米吸钾量的影响

营养型土壤改良剂(以下简称改良剂)施入三种不同肥力水平的土壤进行恒温培养试验和盆栽试验,测定土壤有效钾的含量、盆栽试验玉米的生物量和钾吸收量。结果表明:对于有效钾含量高的土壤,改良剂能促进钾的缓效化,有利于土壤钾的保蓄,防止土壤钾的淋失;对于有效钾含量较低的土壤,改良剂可以活化土壤中的钾,提高土壤钾的有效性;不同肥力水平的土壤,改良剂都能促进玉米对钾的吸收,有利于提高钾肥的吸收利用效率。     

基于小白菜Cd吸收推算土壤Cd安全阈值

Cadmium(Cd), a common toxic heavy metal in soil, has relatively high bioavailability, which seriously threatens agricultural products. In this study, 8 different soils with contrasting soil properties were collected from different regions in China to investigate the Cd transfer coefficient from soil to Chinese cabbage(Brassica chinensis L.) and the threshold levels of Cd in soils for production of Chinese cabbage according to the food safety standard for Cd. Exogenous Cd(0–4 mg kg~(-1)) was added to the soils and equilibrated for 2 weeks before Chinese cabbage was grown under greenhouse conditions. The influence of soil properties on the relationship between soil and cabbage Cd concentrations was investigated. The results showed that Cd concentration in the edible part of Chinese cabbage increased linearly with soil Cd concentration in 5 soils, but showed a curvilinear pattern with a plateau at the highest dose of exogenous Cd in the other 3 soils. The Cd transfer coefficient from soil to plant varied significantly among the different soils and decreased with increasing soil p H from 4.7 to 7.5. However, further increase in soil pH to 8.0 resulted in a significant decrease in the Cd transfer coefficient. According to the measured Cd transfer coefficient and by reference to the National Food Safety Standards of China, the safety threshold of Cd concentration in soil was predicted to be between 0.12 and 1.7 mg kg~(-1) for the tested soils. The predicted threshold values were higher than the current soil quality standard for Cd in 5 soils, but lower than the standard in the other 3 soils. Regression analysis showed a significant positive relationship between the predicted soil Cd safety threshold value and soil p H in combination with soil organic matter or clay content.     

黄土丘陵沟壑区抗侵蚀植物的初步研究

 土壤侵蚀作为山区生态系统退化最主要的驱动力,严重干扰着植被的发育演替过程,植被则通过采用不同的繁殖方式、形态与生理补偿等方式来克服和适应土壤侵蚀造成的负面压力,使植物本身对土壤侵蚀环境的适应性增强,继而发展成为可抵抗土壤侵蚀的植物和群落。凡具有适应土壤侵蚀环境能力,能在土壤侵蚀条件下生存,并能保护改良土壤和具有防止土壤侵蚀的作用,具有繁殖更新能力,可维持群落稳定与可持续发展的植物,称之为抗侵蚀植物。在对黄土丘陵沟壑区植被恢复中不同抗侵蚀植物进行分类、及其侵蚀学特征与土壤侵蚀环境演变特征分析的基础上,提出从土壤侵蚀学观点出发,对植被恢复过程中先后出现的植物和群落的形态学、生理学和生态学特征及防蚀功能进行系统研究,以更好地发挥植物和植被保持水土与改善环境的生态功能。     

Effect of lime and phosphorus on zinc uptake from four soils of Brazil

Abstract

Four soils from southern Brazil were treated with four levels each of lime and P and cropped with corn (Zea mays L.) in the greenhouse. Zinc deficiencies occurred at soil pH values of 6.3 or greater and independently of the rate of P application. Application of P alone did not induce Zn deficiency.     

马铃薯品种（系）农艺性状的适应性和稳定性分析

马铃薯的丰产性、适应性和稳定性是马铃薯推广和应用的重要指标,各种环境因子对不同性状的作用有差异,需要在不同的生态区进行品种（系）的筛选与鉴定。为了筛选出广适、高产、稳产和适宜机械化作业的马铃薯品种（系）,本研究通过GGE双标图对马铃薯高代品系和国内主栽品种的产量和植株性状进行分析,同时阐述基因型与环境互作效应对产量性状和植株性状的影响。前期选育的22份高代品系和13份国内主栽品种分别于2020和2021年种植在渭源县、安定区和永昌县三个试点。测量主茎数等8个植株性状和小区产量等9个产量性状,应用联合方差分析进行显著性水平分析,GGE双标图进行适应性、丰产性和稳定性分析以及试点的区分力和代表性评价。应用联合方差分析结果表明,自然株高、绝对株高的基因型效应显著,基因型效应平方和占总变异平方和比为66.63%、56.56%;花序梗长、单株大薯产量的基因型与环境互作效应显著,互作效应平方和占总变异平方和比为27.86%、27.05%;分支数、单株产量的环境效应显著,环境效应平方和占总变异平方和比为55.82%、25.52%。GGE分析结果表明,品种（系）在不同的年份间,产量和稳定性表现总体较为...     

137Cs示踪分析东北黑土坡耕地土壤侵蚀对有机碳组分的影响

研究土壤侵蚀对有机碳不同组分流失的影响,可为科学评估土壤侵蚀在碳循环中的作用和探明农田有机碳变化机制提供理论依据.该研究以典型黑土区一凸型耕地坡面为研究对象,基于137Cs示踪技术,分析了坡面土壤侵蚀特征及强度分布,定量分析了坡面有机碳组分的变化幅度及侵蚀强度与有机碳组分间的关系.结果表明:研究坡面年均侵蚀速率为380...     

用^137Cs法探讨苏南坡地的土壤侵蚀

与黄土和红壤地区相比 ,学术界对苏南丘陵区土壤侵蚀的关注要少得多 ,也许是这里的土壤侵蚀的绝对数量不大 ,然而 ,苏南地区的土壤侵蚀引起的生态影响却不容忽视 ,如因土壤侵蚀造成的养分流失对水体的影响及土层减薄都远超过黄土区。为了探讨苏南土壤侵蚀的生态影响 ,首先是要了解土壤侵蚀的状况 ,在这方面 13 7Cs示踪法是一种非常有用的工具 ,可是要使用此法 ,必须要解决两个问题 ,一是确定研究区的背景值 ,二是建立估算土壤侵蚀的模型。经过较长时间的研究 ,确定苏南地区的 13 7Cs背景值为 2 2 0 0 Bq/m2 ;并根据基本物理含义 ,建立了耕地与非耕地的土壤侵蚀模型 ,用这 2个模型并借用其他学者提供的土壤沉积模型 ,对宜兴竹园及茶园两个坡地的土壤侵蚀与沉积作了估算。在此基础上 ,又尝试着简单探讨了土壤侵蚀引起的土层及养分流失的生态影响     

The determination of cadmium in soils,plants and fertilizers by dithizone extraction and atomic absorption spectroscopy

Abstract

Methods are proposed for the determination of cadmium in soils, plants and fertilizers.

Soil is first dissolved by treatment with hydrofluoric and hydrochloric acids and plant material is digested with nitric‐perchloric‐sulphuric acids. The cadmium is then extracted from the resulting solutions as the dithizone complex. After destruction of the dithizone the cadmium is dissolved in dilute hydrochloric acid and determined by atomic absorption spectroscopy. Cadmium in phosphatic fertilizers is determined directly by atomic absorption measurement on hydrochloric acid digests of the fertilizer.

The proposed methods have precision adequate for the study of cadmium in soil‐plant systems, the limits of detection being: plant material, 0.004 ppm Cd; soils, 0.02 ppm; and phosphatic fertilizers, 1 ppm.     

褐煤腐殖酸对不同土壤上小麦生长的影响

Humic acid(HA),a fairly stable product of decomposed organic matter that consequently accumulates in ecological systems,enhances plant growth by chelating unavailable nutrients and buffering pH.We examined the effect of HA derived from lignite on growth and macronutrient uptake of wheat(Triticum aestivum L.) grown in earthen pots under greenhouse conditions.The soils used in the pot experiment were a calcareous Haplustalf and a non-calcareous Haplustalf collected from Raisalpur and Guliana,respectively,in Punjab Province,Pakistan.The experiment consisted of four treatments with HA levels of 0(control without HA),30,60,and 90 mg kg -1 soil designated as HA 0,HA 1,HA 2,and HA 3,respectively.In the treatment without HA(HA 0),nitrogen(N),phosphorus(P),and potassium(K) were applied at 200,100,and 125 mg kg -1 soil,respectively.Significant differences among HA levels were recorded for wheat growth(plant height and shoot weight) and N uptake.On an average of both soils,the largest increases in plant height and shoot fresh and dry weights were found with HA 2(60 mg kg -1 soil),being 10%,25%,and 18%,respectively,as compared to the control without HA(HA 0).Both soils responded positively towards HA application.The wheat growth and N uptake in the non-calcareous soil were higher than those of the calcareous soil.The HA application significantly improved K concentration of the non-calcareous soil and P and NO 3-N of the calcareous soil.The highest rate of HA(90 mg kg -1 soil) had a negative effect on growth and nutrient uptake of wheat as well as nutrient accumulation in soil,whereas the medium dose of HA(60 mg kg -1 soil) was more efficient in promoting wheat growth.     

用137Cs示踪法研究密云水库周边土壤侵蚀与氮磷流失

运用137Cs核素示踪技术,研究密云水库周边地区及白河上游地区土壤侵蚀与氮、磷流失状况及其相互之间的量变关系.研究结果表明:从土壤表层(0～20 cm)137Cs分布规律基本符合地形地貌的变化规律,山坡上部的137Cs含量低于山坡中部与坡下部,但是如果山顶具有缓坡或山角下具有陡坡,则137Cs含量变化规律相反.根据土壤137Cs监测数据结果判定该地区基本属于轻度侵蚀和中度侵蚀,部分地区侵蚀情况达到剧烈程度.不同景观与土地利用方式对土壤氮、磷分布有巨大影响:有机质、全氮、水解氮含量均是以灌丛土壤最高,林地次之,与流域内137Cs分布规律相符合;而农田中全磷、速效磷含量最高.不同区域土壤养分含量不同:水库上游地区土壤氮素、磷素含量均低于水库周边地区.证明不合理的人为活动严重的增强了土壤侵蚀程度与养分流失量.回归模拟了土壤中137Cs、(210Pb)与全氮、全磷、水解氮、速效磷含量之间的数学模型.这些模型在区域较小、景观单一的范围内可以定量分析、预报预测各采样区的全磷和有效态氮、磷含量的变化趋势.简化了监测与分析测试程序.扩大了核素示踪技术的应用范围.     

Iron chlorosis and the iron status of soils

Abstract

The iron status of soils and its relation to iron uptake and iron‐chlorosis is discussed. In many soils, the soluble iron level is so low that rather than having to screen against iron uptake, plants are likely limited in their iron uptake by diffusion. The relationship between the plant root‐soil‐iron environment and the plant's ability to alter this environment is related to the development of iron‐chlorosis.     

辽东湾沿岸土壤中~(137)Cs背景值及分布特征研究

在辽东湾沿岸区域采集了20个土壤表层样和7个非耕作土壤剖面样(其中一个为标准剖面),通过对采集的土壤样品中的137 Cs进行测量与分析,确定该区域土壤中137 Cs的背景值,并探讨了土壤中137 Cs的分布特征。结果表明,研究区137 Cs的背景值为(1 704±40)Bq/m2;表层土壤中137 Cs的比活度范围为0.84～19.90Bq/kg,不同土地利用类型表层土壤中的137 Cs比活度有明显差异,比活度高低依次为:草地>盐碱地>耕地;非耕作土壤剖面中137 Cs的总量范围为65～1 535Bq/m2,大部分土壤剖面中137 Cs呈指数递减分布,且剖面中的137 Cs发生不同程度的流失,而受到沉积扰动作用的剖面中137 Cs分布无规律。通过探讨辽东湾沿岸区域土壤中137 Cs的背景值及137 Cs的分布特征,为利用137 Cs示踪技术定量研究该区域物质输移和辽东湾沉积物来源提供依据。     

Wind tunnel test and Cs tracing study on wind erosion of several soils in Tibet

The soils of alpine meadows and alpine grassland steppes, aeolian soils, coarse-grained soils, and farm soils cultivated from alpine grasslands in Tibet are typical soils that are suffering from different degrees of soil erosion by wind. Based on field investigations, wind tunnel experiments, and a ¹³⁷Cs trace study, this work tested the erodibility of these soils by wind, simulated the protective functions of natural vegetation and the accelerative effects of damage by livestock, woodcutting, and cultivation on erosion, and estimated erosion rates from 1963 to 2001. The results indicated that alpine meadows have the strongest resistance to wind erosion, and that undamaged alpine meadow soils generally sustain only weak or no wind erosion. Alpine grassland steppes with good vegetation cover and little damage by humans exhibit good resistance to wind erosion and suffered from only slight erosion. However, soil erodibility increased remarkably in response to serious disturbance by livestock and woodcutting; wind erosion reached 33.03 t ha⁻¹ year⁻¹. The erodibility of semi-stabilized aeolian soil and mobile aeolian soil was highest, at 52.17 and 56.4 t ha⁻¹ year⁻¹, respectively. The mean erosion rates of coarse-grained soil with various levels of vegetation coverage and of farm soil were intermediate, at 45.85 and 51.33 t ha⁻¹ year⁻¹, respectively. Restricting livestock, woodcutting, and excessive grassland cultivation are the keys to controlling wind erosion in Tibet. In agricultural regions, taking protective cultivation and management to enhance surface roughness is a useful way to control wind erosion.     

土壤侵蚀~(137)Cs测定的示踪法原理及其常用模型

简要介绍了137Cs示踪法在土壤侵蚀研究中的应用,内容包括137Cs示踪的基本原理,用于耕地及非耕地土壤侵蚀的常用模型,如非耕地的指数分布模型,耕地的比例模型、容量模型和质量平衡模型,同时对以上几种耕地模型的建模假设、计算公式和应用限制进行了对比分析。     

Varietal difference in radiocesium uptake and transfer from radiocesium deposited soils in the genus Amaranthus

Abstract

Within Amaranthaceae, 33 different varieties, including local varieties from Japan, were grown in 2012 in a field in the town of Iino in the Fukushima prefecture, which is located approximately 51 km north of Tokyo Electric Power Company, Fukushima Daiichi Nuclear Power Plant (FDNPP). The contamination level of the soil was 2770 ± 140 Bq kg^?1 dry weight (¹³⁴Cesium (Cs) + ¹³⁷Cs, average ± SE), and the field was also cultivated in 2011. There was a significant varietal difference in the dry weight production, radiocesium accumulation and transfer factor (TF) of radiocesium from the soil to the plant. The ratio of the lowest TF to the highest TF was approximately 3. Because the ratio of ¹³⁷Cs to ¹³³Cs was significantly positive, radiocesium seems to be absorbed in a manner similar to that of ¹³³Cs. It is suggested that the varietal difference in the behavior of radiocesium uptake mainly depends on its genetic background rather than on environmental factors.     

Soil Redistribution investigations by combined use of soil 137Cs and selected chemical properties

Abstract

To improve the methods of application of phosphorus or supply of soil P to Azolla (A. microphylld), basal application, split application, inoculation of P-enriched Azolla, and soil disturbance were compared. Soil disturbance did not increase the floodwater P content. Phosphorus was applied to inoculum production plots to enrich Azolla with P. Thus, phosphorus-enriched Azolla could multiply 5–7 times after inoculation until it became P deficient. Trials on the methods of enrichment of Azolla with P showed that the best method was to broadcast twice 4.33 kg P (10 kg P₂O₅/ha) at 2-day intervals and to harvest Azolla 3 days after P application. Addition of P once or twice 2 weeks after the inoculation of P-enriched Azolla further increased the biomass production. Efficiency of P application was analyzed in terms of N gain in relation to the amount of P applied. This ratio in the P-enriched Azolla treatment was higher than the economically sound ratio -5-, and higher than or equal to that in the standard split application.