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1.
The Foliar Uptake by Squash Plant

The radioactive ash for experimental use, hereafter referred to as “Bikini ash”, was prepared by igniting the heavily contaminated substances on board No. 5 Fukuryu Maru at about 650°C, followed by sifting through a 100 mesh sieve. On ignition some parts of the fission products, particularly iodine, ruthenium and tellurium would have possibly been lost to the air.  相似文献   

2.
Introduction

In the preceding paper,1) the author pointed out the necessity of investigating the contaminating radioactive elements in agricultural crops. In this paper. a simple radiochemical treatise on the contaminated plants is discussed.  相似文献   

3.
Introduction

New H-bombs detonated from March-May 1954 at Bikini atoll not only gave unexpected disaster to crew on board No. 5 Fukuryu-Maru, a tunafishing boat which happened to be in the neighbourhood (43 miles away from) the dangerous area, but also brought a somewhat high radioactive fall-out all over Japan.  相似文献   

4.
Radioactive contamination of soils is considered as a separate type of degradation decreasing their fertility. Natural soil radioactivity is described. The main sources of technogenic radionuclides for the soil cover (global radionuclide fallout after nuclear weapons tests, the operation of nuclear facilities, radioactive waste) were shown. The phytomelioration of soils containing radionuclides was assessed. Issues were analyzed related to the remediation of agricultural soils after radiation accidents associated with the release of radionuclides into the environment: the discharge of radionuclides into the Techa River (1949–1953) and the Kyshtym (Southern Urals, 1957), Windscale (United Kingdom, 1957), and Chernobyl (Ukraine, 1986) accidents. The hazard of radioactive contamination of the soil-plant cover was assessed from two viewpoints: the anthropocentric (sanitary-hygienic) principle, when the degree of radioactive contamination of agricultural crops and the conformity of their radionuclide content to radiological standards are taken into account (maximum permissible concentrations of radionuclides), on the one hand, and the ecocentric (biospheric, environmental) approach, when the consequences of the irradiation of soil biota and living terrestrial organisms caused by radionuclides present in the soils are taken into account (conformity to the radiation standards and permissible radiation doses), on the other hand. For some technogenic radionuclides, the use of these principles for assessing the hazard of radioactive contamination of the soil was exemplified, which is of importance for determining the rehabilitation strategy of agricultural lands contaminated with radionuclides.  相似文献   

5.
2011年3月日本福岛核电站发生核泄漏事故,释放出大量放射性物质,使周边农田受到直接污染。其中对水稻影响最为严重的放射性核素为放射性铯。分析表明:水稻对铯的吸收是存在差异的,钾肥能有效降低水稻中铯含量,而氮肥会增加其铯含量;距离福岛核电站距离越远其受污染程度越低;土壤中铯的浓度、含钾量、固定铯的能力和耕作表土的厚度都影响着铯的转移;此外,水稻本身的品种也影响着对铯的吸收。水稻去污染的方法包括:利用蓝藻除去表土中放射性铯、对土壤进行深耕及防止水田二次污染等方式来降低土壤本身铯含量;另一方面通过改变土壤粒度分布,向土壤中加入施威特曼石、沸石和蛭石及控制肥料比例等方式来抑制土壤中铯的转移。以上除污染方法的综合应用效果十分显著,福岛县水稻含铯量于2014年已全部低于25 Bq/kg。该研究为中国构建农作物放射性污染特征数据库及相关应急管理提供参考。  相似文献   

6.
The effect of Co and Zn on the accumulation of 60Co and 65Zn by plants was studied in experiments with growing barley on a soddy-podzolic soil and a chernozem containing the radionuclide and increasing concentrations (from the background level to a high degree of contamination) of the corresponding metal. The root uptake of 60Co was directly related to the soil contamination with Co and its accumulation in the plants, while an inverse relationship was observed between the activity of 65Zn in the plants and the content of Zn in the soil. It was concluded that the transfer of the radionuclide into the plants under mixed radioactive and chemical contamination depended, on the one hand, on the mobile reserve of the stable nuclide in the soil and the solid phase potential to release its ions into the soil solution and, on the other hand, on the requirement of the plants for this element and the uptake rate of its ions by the roots from the solution.  相似文献   

7.
To avoid loss of yield, crops must maintain tissue potassium (K) concentrations above 5–40 mg K (g DM)–1. The supply of K from the soil is often insufficient to meet this demand and, in many agricultural systems, K fertilisers are applied to crops. However, K fertilisers are expensive. There is interest, therefore, in reducing applications of K fertilisers either by improving agronomy or developing crop genotypes that use K fertilisers more efficiently. Agronomic K fertiliser use efficiency is determined by the ability of roots to acquire K from the soil, which is referred to as K uptake efficiency (KUpE), and the ability of a plant to utilise the K acquired to produce yield, which is referred to as K utilisation efficiency (KUtE). There is considerable genetic variation between and within crop species in both KUpE and KUtE, and chromosomal loci affecting these characteristics have been identified in Arabidopsis thaliana and several crop species. Plant traits that increase KUpE include (1) exudation of organic compounds that release more non‐exchangeable soil K, (2) high root K uptake capacity, (3) early root vigour, high root‐to‐shoot ratios, and high root length densities, (4) proliferation of roots throughout the soil volume, and (5) high transpiration rates. Plant traits that increase KUtE include (1) effective K redistribution within the plant, (2) tolerance of low tissue K concentrations, and, at low tissue K concentrations, (3) maintenance of optimal K concentrations in metabolically active cellular compartments, (4) replacement of K in its non‐specific roles, (5) redistribution of K from senescent to younger tissues, (6) maintenance of water relations, photosynthesis and canopy cover, and (7) a high harvest index. The development of crop genotypes with these traits will enable K fertiliser applications to be reduced.  相似文献   

8.
Journal of Soils and Sediments - Natural degradation of petroleum hydrocarbons (PHC) is a crucial process to consider when managing contaminated soils. However, the degradation rate is dictated by...  相似文献   

9.
Abstract

The accident at Fukushima Dai-Ichi Nuclear Power Station (NPS) extensively contaminated the agricultural land in the Tohoku region of Japan with radioactive cesium [sum of cesium-134 (134Cs) and cesium-137 (137Cs)]. We evaluated the status of radioactive cesium (Cs) contamination in soil and plants at the Field Science Center of Tohoku University, northern Miyagi prefecture, 150 km north of the NPS. In seven pastures with different management, we examined: (1) the distribution of radioactive Cs in soil, (2) the concentration of radioactive Cs in various herbaceous plant species and (3) the change in radioactive Cs content of plants as they matured. We collected samples of litter, root mat layer (root mat soil and plant roots), and subsurface soil (0–5 cm beneath the root mat) at two to three locations in each pasture in December 2011 and May 2012. The aboveground parts of herbaceous plants (four grasses, two legumes, and one forb species) were collected from May 9 to June 20, 2012, at 14-d intervals, from one to five fixed sampling locations in each pasture. The distribution of radioactive Cs in soil differed among pastures to some degree: a large proportion of radioactive Cs was distributed in the root mat layer. Pasture management greatly influenced the radioactive Cs content of herbaceous plants (p < 0.001); plant species had less influence. Radioactive Cs content was highest (> 3 kBq kg?1 dry weight) on May 9 and significantly decreased with maturity (p < 0.001) for most of the pastures, whereas it remained low (0.04–0.18 kBq kg?1 dry weight) throughout the measurement period in the pasture where composted cattle manure was applied. The soil-to-plant transfer factor was negatively correlated to pH(H2O) (R2 = 0.783, p < 0.001) and exchangeable K content (R2 = 0.971, p < 0.001) of root mat soils, which suggests that surface application of composted cattle manure reduces plant uptake of radioactive Cs by increasing the exchangeable K content of the soil. The radioactive Cs content of plants decreased with plant maturity; its degree of decrease (May 9 to June 6) was smaller in legumes (80.6%) than grasses (55.5%) and the forb (58.6%). Radioactive Cs content decreased with plant maturity; also, the proportion remaining in the aboveground plant was higher in legumes (80.6%) than grasses (55.5%) and the forb (58.6%).  相似文献   

10.
The upper soil horizons are strongly contaminated in the area influenced by the Mid-Urals copper smelter. In the technogenic desert and impact zones, the contents of a number of elements (Cu, Zn, As, Pb, P, and S) by many times exceed their clarke values and the maximum permissible concentrations (or provisional permissible concentrations). The degree of technogeneity (Tg) for these elements is very high in these zones. In the far buffer zone, Tg is about zero for many elements and increases up to Tg = 27–42% for four heavy elements (Cu, Zn, Pb, and As) and up to 81–98% for P and S. The buffer capacity of the humus horizon depends on the soil’s location within the technogeochemical anomaly and also on the particular pollutant. In the impact zone, it is equal to 70–77% for lead and arsenic, although other technogenic elements (Zn, Cr, S, and P) are poorly retained and readily migrate into the deeper horizons (the buffer capacity is equal to 14–25%). Nearly all the heavy metals enter the soil in the form of sulfides. The soils in the area affected by the Noril’sk mining and smelting metallurgical enterprise are subdivided into two groups according to the degree of their contamination, i.e., the soils within Noril’sk proper and the soils in its suburbs to a distance of 4–15 km. The strongest soil contamination is recorded in the city: the clarke values are exceeded by 287, 78, 16, 4.1, and 3.5 times for Cu, Ni, Cr, Fe, and S, respectively. The major pollutants enter the soil from the ferruginous slag. The soil’s contamination degree is lower in the suburbs, where heavy metal sulfides reach the soils with the aerial emission from the enterprise.  相似文献   

11.
Increased paddy yields due to algal inoculation were earlier reported in controlled pot and field experiments (1–8). The present communication deals with a field trial conducted in a cultivator's field at Vasudevanallur in Madras State, during November 1966 to March 1967, with ASD 5 paddy variety. The paddy cultivation in the field followed a groundnut crop.  相似文献   

12.
Characteristics of heavy metal contamination in paddy soils were discussed with respect to the soil and field conditions influencing the metal contents in rice.

1. In contaminated areas along the Kuzuryu River, the heavy metal contents of rice (expressed as the average of each area) were largely related to contents of paddy soils in 0.1 N HCl soluble forms as well as in total contents. A correlation was also found for the ratio of Cd to Zn in their soluble forms in the soil.

2. Within a given contaminated field plot, the heavy metal contents were not uniform, i.e: they were high around the irrigation inlet and decreased towards the outlet. However, these changes seemed to alter the Cd rice level much less than expected.

3. Soil pH and exchangeable Ca were negatively correlated with the Cd content of rice at a highly significant level. An un-drained field condition with a low soil Eh remarkably lowered the Cd content, particularly during rainy weather after the heading of the plant.

4. Based on a comparison of the extractable heavy metal contents in the waste ores and their contaminated soils, sulfide minerals derived from the mining appeared to be weathered more rapidly in the soil. With some extraction methods, the Cd origin was distinguished as the solubility of the metal in the soil among the waste products from the zinc mining and refinery.  相似文献   

13.
A total of 373 species of wild relatives of crop plants representing 120 genera and 48 families were collected from different phytogeographical regions of India during a mission mode sub-project on Sustainable Management of Plant Biodiversity under National Agricultural Technology Project during 1999–2005. Significant diversity representing endemic/rare/endangered species has been discussed in this paper. The information on phytogeographical distribution, life form, economic types and assessment of threat has also been included. Thrust areas for future target collections and conservation have been discussed to serve as reference for management of genetic resources.  相似文献   

14.
This paper is dedicated to the problem of radioactive contaminated lands?? assessment. We suggest the mechanisms of land value calculation under radionuclide contamination, accountability of such factors as internal and external human irradiation, migration of radionuclides in soil profile, and accountability of the own soil value in the totals sheet, as well as ecosystem services from the assessment facility. The approbation of the suggested method for the conditions of the Tula region is also presented.  相似文献   

15.
Detached leaves of several crop plants were cultured in a nutrient solution containing 32P, and the 32P mobility between and within organs was investigated. The results obtained were as follows: 1) In soybean and adzuki bean, 32P was well distributed all over the leaf blade and petiole within 24 h after 32P absorption, though the transfer of 32P from the leaf vein to the mesophyll varied among the varieties. 2) In rice, 32P reached the middle or proximal part of the leaf blade within 48 h after 32P absorption. The gradient of 32P density decreased distally. 3) In maize and pumpkin, a small amount of 32P reached the leaf blade; in maize, the gradient of 32P density was similar to that in rice, though 32P was retained in the whole petiole in pumpkin. Besides transpiration, 32P transfer from xylem to mesophyll and structures of leaf tissues could be considered to regulate the 32P mobility.  相似文献   

16.
Extraordinary features of submerged rice soils and its relation to manuring practices has long been the problem of study to increase the average and maximum yield of rice per unit area. Out of these studies many remarkable results have so far been achieved, the mention of which in dentail is not possible in this paper. But in a summarized way it can be easily concluded that during the growth cycle of rice plant nitrogen is most important limiting fertilizer element and its need for the plant is multi-sided. The practical experience of the farmers of Shizuoka prefecture is quite in agreement with this, as they say that in rice-culture fertilizer should be applied at the transplanting time and a little before actual heading. Regarding the late dressing which is called (Hogoe) they have strong belief that it is effective in most of the cases. Taking this into account, in 1933 YAMAMOTO and SUZUKI(18) started to study as to when top dressing be applied with the help of pot experiments, and Were able to conclude that a top dressing of 0.5 g per pot was quite effective. This report is the first to be published on the top-dressing aspect of rice, but it does not seem to be a complete one. A field experiment for such a study was conducted by GOTO(1) in the year 1942. In his experiment, he used ammonium sulphate for top dressing with 3 dates viz. a) Maximum tillering b) Late tillering and c) Panicle formation. He concluded that amm. sulphate as top-dressing is mostly absorbed in the panicle formation stage and is utilized for grain formation. He also stressed the importance of top-dressing at the panicle formation stage.  相似文献   

17.
Tea (Camellia sinensis (L.) Kuntze) plantations in the northern part of Ibaraki Prefecture in Japan, approximately 100 km southwest of the Fukushima Daiichi Nuclear Power Station (FDNPS), were contaminated with radioactive cesium (Cs) released from the power station during the Fukushima Daiichi Nuclear Disaster in 2011. Radioactive Cs concentrations in new shoots were monitored over the 3 years since June 2011. The use of conventional skiffing management resulted in 64% lower radioactive Cs concentration in October 2011 compared with that in June 2011, and the concentration continued to decrease gradually thereafter. Medium pruning to approximately 40 cm from the ground decreased radioactive Cs concentrations in the first tea crop of 2012 and 2013 by 24–25% more than conventional skiffing management.  相似文献   

18.
A field experiment was conducted to study the effects of peat amendment and crop production system on earthworms. The experiment was established on a field previously cultivated with oats and with silt as the main soil type. Perennial crops strawberry, timothy and caraway, and annual crops rye, turnip rape, buckwheat, onion and fiddleneck were cultivated with conventional methods. All the crops were grown with and without soil amendment with peat. Earthworms were sampled twice: 4 and 28 months after establishment of the experiment. In the former case part of the experimental plots were soil sampled and hand sorted for estimation of earthworms. In the latter case all experimental plots were sampled and both soil sampling and mustard extraction was carried out. Soil organic carbon and microbial biomass was measured at 14 and 28 months. Peat increased the abundance of juvenile Aporrectodea caliginosa by 74% in three growing seasons, but had no effect on adult numbers. Lumbricus terrestris numbers were not increased by peat treatment. Three season cultivation of caraway favoured both A. caliginosa and L. terrestris. An equal abundance of A. caliginosa was also found in plots cultivated with turnip rape and fiddleneck. Total earthworm and especially A. caliginosa numbers were very small in plastic-mulched strawberry beds. This was mainly attributed to repeated use of the insecticide endosulfan. With the strawberry plots omitted there was a significant correlation between soil microbial N measured at 14 months and juvenile Aporrectodea spp. and Lumbricus spp. numbers measured at 28 months. Adult earthworm numbers were not associated with either soil organic C or microbial biomass.  相似文献   

19.
基于颜色特征的绿色作物图像分割算法   总被引：18，自引：13，他引：5  
绿色作物的识别是农业机械视觉系统的重要研究内容之一,该文采用RGB颜色系统,基于统计分析提出了一种绿色作物图像分割方法。从简单物体光照颜色模型方面,分析了RGB颜色空间中作物绿色“恒量”（Gvalue>Rvalue and Gvalue>Bvalue）的存在性,构建了作物图像分割相对错误率评估模型。并与传统颜色索引方法Excess Green (ExG)+auto-threshold进行了对比分析。试验结果表明,在正常光照条件下：1）采用的算法对田间不同作物-土壤组图像分割的相对错误率均有显著影响;其中,相对ExG+auto-threshold算法,采用RGB算法的结果图像中大多能保留油菜、大豆和甘蔗的形态学特征;2）采用的算法、光照变化以及算法与光照变化的交互作用均对室外美人蕉图像分割的相对错误率有显著影响;其中,相对ExG+auto-threshold算法,采用RGB算法的结果图像中大多能去除背景噪声。单因子方差分析进一步表明,光照变化对采用ExG+auto-threshold算法分割图像的阈值有显著影响。该文提出的RGB算法相对传统的ExG+auto-threshold绿色索引,对于早期生长的绿色作物是一种有效、简单的图像分割方法,对作物-土壤、光照变化不敏感。  相似文献   

20.
The specificity of contamination of permafrost-affected soils with radionuclides derived from an accidental underground nuclear explosion at the Kraton-3 polygon located in the northern taiga subzone has been studied in northwestern Yakutia. It is shown that the high density of the radioactive contamination is preserved in the soils 23 years after the nuclear accident. The concentrations of 137Cs and 90Sr vary from 34 to 1025 and from 57 to 781 kBq/m2, respectively, which is 30–1000 times higher than the global fallout of these radionuclides.  相似文献   

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