Compound pollution of Cd, Pb, Cu, Zn, and As on lowland rice

Cd, Pb, Cu, Zn, and As are typical pollutants originated from Pb-Zn mine, smelting waste water discharge/irrigation and gas emission,and they were distributed widely in China. We studied the compound pollution of Cd, Pb,Cu, Zn, and As on rice.     

毛细管离子分析法测定茶叶中的锌、锰、铜、铅和镉

用毛细管离子分析(CIA)法测定了茶叶中的锌、锰、铜、铅和镉,在10mmol/L咪唑,10mmol/Lα-羟基乙酸,pH=4.0的电泳介质中,五种离子在10min内得到了分离,用间接紫外法检测,以外标法定量,五元素的线性关系良好,相关系数为0.9973~0.9997,平均回收率在96.4%~104.2%之间,相对平均偏差为2.1%~3.3%,检测限为0.02~0.2μg/ml。此方法快速简便、准确度高、测定成本低。     

不同花生品种重金属Cu、Zn、Pb、Cd、Cr富集与转运规律

以青岛市8个主栽花生品种为试材,通过相同土壤条件下大田种植和室内检测分析,对花生植株不同器官中Cu、Zn、Pb、Cd和Cr重金属元素的吸收、富集与转运规律进行了研究。结果表明,供试的8个花生品种植株根系中Cu、Zn、Pb和Cd含量存在显著性差异,茎叶中Cu、Zn、Pb和Cr含量存在显著性差异,籽仁中Cu、Zn、Pb、Cd和Cr含量均存在显著性差异,果壳中Cu、Zn和Cd含量存在显著性差异;供试的8个花生品种籽仁中Cd含量均超过了农业部无公害花生Cd≤0.05 mg.kg-1的卫生限量标准。花生植株各器官对重金属的平均生物富集量顺序：根系和果壳为Zn〉Cu〉Cr〉Pb〉Cd,茎叶和籽仁为Zn〉Cu〉Pb〉Cr〉Cd。花生植株各器官的平均转运量系数顺序：茎叶为Pb〉Zn〉Cd〉Cr〉Cu,籽仁为Zn〉Cu〉Cd〉Pb〉Cr,果壳为Cr〉Cu〉Zn〉Pb〉Cd。A4为花生籽仁低Pb吸收富集型品种,A3为花生籽仁低Cd吸收富集型品种。     

Effect of Si soil amendments on As,Cd, and Pb bioavailability in contaminated paddy soils

Paddy and Water Environment - Numerous greenhouse and laboratory experiments have shown that the application of Si-rich materials may affect the mobility and transport of hazardous elements in the...     

Chemical fractionation of seven heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, and Zn) in selected paddy soils of Iran

The content and fractionation of seven heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, and Zn) were determined in 28 surface soil samples (0–20 cm) of agricultural topsoil from Isfahan Province in central Iran. The order of abundance of metals in the soils was Fe (1240.4 mg kg^?1) > Mn (95.7 mg kg^?1) > Pb (51.6 mg kg^?1) > Zn (23.8 mg kg^?1) > Ni (13.4 mg kg^?1) > Cu (7.0 mg kg^?1) > Cd (2.8 mg kg^?1). Iron, Mn, Ni, Pb, and Zn existed in paddy soils mainly in Fe-Mn oxides (53.6 %, 65.2 %, 40.4 %, 40.8 %, 53.3 %, respectively), whereas Cu and Cd occurred essentially as residual mineral phase (41.4 %) and carbonate (36.1 %), respectively. The mobile and bioavailable fractions of Cd, Cu, Fe, Mn, Ni, Pb, and Zn in paddy soils averaged 48.8, 20.8, 0.79, 29.2, 28.5, 41.1, and 24.8 %, respectively, which suggests that the mobility and bioavailability of the seven metals probably decline in the following order: Cd > Pb > Mn ≥ Ni > Zn > Cu ? Fe, suggesting greater contribution of anthropogenic Cd. As Cd in soil is easily accumulated by plants through the root system, the concentration of Cd in these paddy soils could be a concern to human health.     

Effect of Grain Position within a Panicle and Variety on As, Cd, Cr, Ni, Pb Concentrations in japonica Rice

Two japonica rice varieties, a compact panicle (CP) Xiushui 63 and a loose panicle (LP) Xiushui 11 were grown in a slightly contaminated paddy field, to determine the effect of grain positions within a panicle and variety on grain As, Cd, Cr, Ni and Pb concentrations. There was a significant difference in grain As, Cd, Cr, Ni and Pb concentrations among grain positions, and the extent of the difference was variety- and metal-specific; Xiushui 63 showed greater difference than Xiushui 11, and As, Cd, Cr and Pb being greater than Ni. The top grains (TG) of a panicle had higher As, Cd and Ni concentrations than the middle ones (MG), and the bottom ones (BG) contained the lowest. With regard to Cr and Pb, the case was opposite. Significantly positive correlations were found between grain weight and As, Cd, Ni concentrations, but there was a negative correlation between grain weight and Cr, and Pb concentrations. There was a remarkable variation in grain filling pattern among grains within a panicle, and between Xiushui 63 and Xiushui 11. In comparison with MG and TG, BG had the lowest grain filling rate and grain weight, leading to obvious difference in grain weight among grains within a panicle, and a greater difference for Xiushui 63 than for Xiushui 11. The regression analysis showed that grain As and Cd concentrations were positively correlated with the maximum grain filling rate (GRm),while negatively correlated with the required time for reaching the maximum grain filling rate (Tpol). Concerning Cr and Pb, the case was just reverse. It is suggested that As and Cd accumulation in grains might be accompanied by the carbohydrate accumulations, while Cr and Pb accumulation displayed a different pattern.     

Bird,weed and interaction effects on yield of irrigated lowland rice

Weeds and grain feeding birds are the two main biological causes of yield losses in irrigated rice in Africa. To quantify the single and combined effect of these biological constraints on rice yields, and to investigate whether weeds attract birds and thereby contribute to increased bird damage, a three-year factorial experiment was set-up in the Senegal River Valley. We tested two management factors (bird and weed management), each with two levels (‘complete’ and ‘absent’), and one crop cycle factor also with two levels (Sahel 202, a medium-cycle and Sahel 108, a short-cycle rice cultivar). Season-long competition from weeds resulted in high but predictable yield losses ranging from 50% to 75%, with lower yield losses for the medium-cycle cultivar Sahel 202 in two of the three seasons. Due to the nature of the pest, season-long exposure to birds resulted in less predictable yield losses ranging from 13% to as high as 94%, with high seasonal variation. In two seasons, much lower bird-inflicted yield losses were observed in the short-cycle cultivar Sahel 108, whereas in one season the medium-cycle cultivar Sahel 202 was much less damaged. When rice was exposed to both weeds and birds, the relative yield losses ranged from 80 to 99%. The yield reducing effect of weeds and birds was never additive. Bird visits to a weedy crop were more frequent compared to a weed-free crop at least in the early rice grain filling stages. This attraction of birds by weeds resulted in an additional yield loss in five of the six cases, ranging from 2 to 62%. Bird-inflicted yield losses in irrigated rice may be reduced by keeping the crop, as much as possible, free from weeds.     

晚粳稻籽粒中砷、镉、铬、镍、铅等重金属含量的品种和粒位效应

 选用籽粒着粒密度差异较大的密穗型品种秀水63和散穗型品种秀水11，种植于受重金属轻度污染的土壤，研究了晚粳稻籽粒中有毒重金属As、Cd、Cr、Ni、Pb含量的品种与粒位效应。结果表明，重金属含量的粒位间差异秀水63明显大于秀水11，As、Cd、Cr、Pb含量粒位间差异显著， Ni含量差异较小。穗上部籽粒As、Cd、Ni含量高于中部籽粒，穗下部籽粒最低，而Cr、Pb则正好相反。稻米中几种重金属含量与粒重的关系因重金属种类不同存在着差异，籽粒As、Cd、Ni含量与粒重呈正相关，而Cr和Pb含量与粒重呈负相关。秀水63和秀水11不同粒位的籽粒灌浆模式存在差异，下位粒灌浆速率较低，使粒重较上、中位粒低，导致粒重有较大的粒位差异，而这种差异也与穗部着粒密度有关，秀水63明显大于秀水11。籽粒As、Cd、Ni含量与最大灌浆速率（GRm）呈正相关，与到达最大灌浆速率时间（Tpoi）呈负相关，而Cr和Pb含量与以上两个籽粒灌浆特性参数分别呈负相关和正相关，说明籽粒As、Cd、Ni的积累与碳水化合物的积累具有相同或相近的模式，而Cr和Pb表现为不同的积累模式。     

Zn, Cu, Cd and Hg binding to metallothioneins in harbour porpoises Phocoena phocoena from the southern North Sea

Background  

Harbour porpoises Phocoena phocoena from the southern North Sea are known to display high levels of Zn and Hg in their tissues linked to their nutritional status (emaciation). The question arises regarding a potential role of metallothioneins (MTs) with regard to these high metal levels. In the present study, metallothionein detection and associated Zn, Cd, Cu and Hg concentrations were investigated in the liver and kidney of 14 harbour porpoises collected along the Belgian coast.     

花生B、Cu、Mo、Zn肥配施效应研究

通过田间试验和室内分析相结合的方法，研究了皖中岗地花生配合施用B、Cu、Mo、Zn等不同微量元素肥料的效果及其对花生生长发育及产量形成的影响，结果表明，在N，P，K大量元素一定的供给水平上，合理配施B，Cu,Mo,Zn等，对花生的生长发育和产量形成均有显著效果，四种微量元素与N，P，K配施均能促进花生生长，有利于植株干物质积累，增加根瘤数和结果数，提高花生产量和经济效益。其中以配施硼肥和钼肥或配施铜肥的增产增收效果最为显著。推荐N150，P150，K120，B9，Cu15,Mo30作为花生高产平衡施肥的配方。     

Yield constraints of rainfed lowland rice in Central Java, Indonesia

The low and unstable yields of rainfed lowland rice in Central Java can be attributed to drought, nutrient stress, pest infestation or a combination of these factors. Field experiments were conducted in six crop seasons from 1997 to 2000 at Jakenan Experiment Station to quantify the yield loss due to these factors. Experimental treatments—two water supply levels (well-watered, rainfed) in the main plots and five fertilizer levels (0-22-90, 120-0-90, 120-22-0, 120-22-90, 144-27-108 kg NPK ha⁻¹) in the subplots—were laid out in a split-plot design with four replications. Crop, soil, and water parameters were recorded and pest infestations were assessed.

In all seasons, rice yield was significantly influenced by fertilizer treatments. Average yield reduction due to N omission was 42%, to K omission 33–36%, and to P omission 3–4%. Water by nutrient interactions did not affect rice yield and biomass production. In two of the three dry seasons, an average of 20% of the panicles were damaged by pests and estimated yield loss from pests was 56–59% in well-watered and well-fertilized treatments. In one out of six seasons, yields under rainfed conditions were 20–23% lower than under well-watered conditions. Drought, N and K deficiencies, and pest infestation are the major determinants for high yields in rainfed environments in Jakenan. Supplying adequate nutrient and good pest control are at least as important as drought management for increasing crop productivity of rainfed rice-growing areas in Central Java. The relative importance of drought, nutrient and pest management may vary in other rainfed areas. Yield constraints analysis should be systematically carried out to identify appropriate management strategies.     

Potassium balances in rainfed lowland rice on a light-textured soil

An experiment, over 3 years, studied the effects of mineral fertilizers and organic manures on potassium (K) balances in rainfed lowland rice on a light-textured Tropaqualf. Two rice crops were grown each year: the first direct seeded (DS) in moist soil that was later flooded by monsoon rain; the second transplanted (TP) into flooded soil towards the end of the wet season. A soybean crop followed the TP rice in the first year. In all the fertilizer and manure combinations studied, removal of K in the crop exceeded K additions and the soil K balance was negative unless crop residues were incorporated. For DS rice the relations between grain yield and K uptake fell within the limits of maximum K dilution and maximum K accumulation expected for well-managed irrigated rice. But those for TP rice tended to fall below the limit of maximum accumulation, yield being constrained by factors other than mineral nutrition, especially water deficit. In the DS rice, grain yields per unit K uptake were close to maximal in the treatments that received no K, but they were well below that in the K-fertilized treatments. Uptake was well correlated with exchangeable K in the soil at maximum tillering measured by ammonium acetate extraction. The mass balances of K inputs, K uptake and exchangeable K in the soil however, showed that a large part of the uptake was from non-exchangeable pools. The mobilization of non-exchangeable K was apparently plant-induced and was greater in treatments with greater growth. A mechanism for root-induced solubilization of non-exchangeable K, peculiar to rice growing in flooded soil, is proposed.     

Effect of irrigation method and N-fertilizer management on rice yield, water productivity and nutrient-use efficiencies in typical lowland rice conditions in China

Alternate wetting and drying irrigation (AWD) has been reported to save water compared with continuous flooding (CF) in rice cultivation. However, the reported effects on yield varied greatly and detailed agro-hydrological characterization is often lacking so that generalizations are difficult to make. Furthermore, it is not known how AWD modifies nutrient use efficiencies and if it requires different N-fertilizer management compared with CF. This study quantified the agro-hydrological conditions of the commonly practiced AWD and compared the impact of AWD and CF irrigations at different N-fertilizer management regimes on rice growth and yield, water productivity, and fertilizer-use efficiencies in five crop seasons in 1999 and 2000 at two typical lowland rice sites in China (Jinhua, Zheijang Province and Tuanlin, Hubei Province), with shallow groundwater tables.Grain yields varied from 3.2 to 4.5 t ha^–1 with 0 kg N ha^–1 to 5.3–8.9 t ha^–1 with farmers N-rates (150 kg N ha^–1 in Jinhua and 180 in Tuanlin). In both sites, no significant water by nitrogen interaction on grain yields, biomass, water productivity, nutrient uptakes and N-use efficiency were observed. Yield and biomass did not significantly differ (P >0.05) between AWD and CF and among N timings. The productivity of irrigation water in AWD was about 5–35% higher than in CF, but differences were significant (P <0.05) only when the rainfall was low and evaporation was high. Increasing the number of splits to 4–6 times increase the total N uptake, but not total P-uptake, and total K-uptake compared with farmers practices of two splits. Apparent Nitrogen recovery (ANR) increased as the number of splits increased, but there was no significant difference in ANR between AWD and CF. During the drying cycles of AWD irrigation, the perched water table depths seldom went deeper than – 20 cm and the soil in the root zone remained moist most of the time. The results suggest that in typical irrigated lowlands in China, AWD can reduce water input without affecting rice yields and does not require N-fertilizer management differently from continuous flooding. The results can be applied to many other irrigated lowland rice areas in Asia which have a shallow groundwater table.     

Cd、Cr、Pb复合胁迫下小麦植株重金属的积累与分布

为了预测重金属复合胁迫对小麦的危害,采用溶液培养、田间土柱栽培等毒理试验方法,分析了小麦幼苗期及成熟期Cd、Cr、Pb在植株不同器官的富集,并对小麦受重金属胁迫的安全限量值进行了研究。结果表明,①Cd、Cr、Pb二元或三元胁迫条件下,小麦幼苗期植株各器官对重金属的富集浓度均极显著高于单一胁迫处理,说明复合胁迫加剧了重金属向小麦体内的迁移累积。成熟期小麦对Cd、Cr、Pb的富集比较依赖于土壤中相应Cd、Cr、Pb的浓度水平,其他两种重金属的协同作用在根系所占比例大约为5.09%～21.66%。②各器官中重金属的富集表现:幼苗期为根系>叶鞘>叶片,成熟期为根系>茎叶>籽粒。但幼苗期复合胁迫促进了重金属向地上部分的转移。③幼苗期植株各器官对重金属富集系数的大小为Cr>>Pb>Cd,表明幼苗期小麦根系对Cr的富集能力最强;植株地上部分的重金属平均富集量Cd为68.68%、Cr为51.63%、Pb为70.83%,说明Cd、Pb运输到地上部的能力较强。成熟期Cd在小麦地下、地上各器官的转移速率最快,Cr次之,而Pb转移到籽粒中去的量很少。     

The effect of toposequence position on soil properties,hydrology, and yield of rainfed lowland rice in Southeast Asia

A large proportion of rainfed lowland rice in Southeast Asia is grown in gently sloping areas along toposequences with differences in elevation of a few meters. These small differences in elevation can lead to differentiation in soil properties and hydrological conditions, which in turn may affect crop performance and yield. It may be appropriate to replace blanket crop management recommendations in rainfed areas with toposequence-specific management recommendations. However, thorough statistical analyses of the relationships between toposequence position and field and crop conditions are lacking. In this paper, we statistically analysed the effect of toposequence position on soil properties, hydrological conditions, yield, and yield increase due to weed control and/or fertilizer management in rainfed areas in four villages in Indonesia and Thailand each in 2000–2002.     

Effects of water regime,nitrogen fertilization,and rice plant density on growth and reproduction of lowland weed Echinochloa crus-galli

Direct-seeded rice systems are increasing in Asia as farmers respond to the high labor cost and shortage of water. Echinochloa crus-galli is one of the most problematic and competitive weeds in direct-seeded rice systems. Because of concerns about excessive herbicide use, there is an interest in developing cultural weed management strategies. However, the design of such strategies requires a better understanding of the weed response to crop density, nutrition, and water regime. A study was therefore conducted in pots to determine the effect of water (flooded and aerobic), nitrogen (N) fertilization (0, 100, and 200 kg N ha⁻¹), and rice density [0, 4 rice plants (≈20 kg seed ha⁻¹), and 16 rice plants (≈80 kg seed ha⁻¹)] on the growth and reproduction of E. crus-galli. When grown alone, the growth and seed production of E. crus-galli were higher in flooded conditions than in aerobic conditions. However, no such differences were observed when E. crus-galli was grown with rice interference. E. crus-galli growth and seed production increased with increases in N rate. Irrespective of water regime and N rate, the growth and seed production of E. crus-galli declined with increases in rice density. At 100 kg N ha⁻¹, for example, E. crus-galli shoot biomass and seed production decreased by 84–86% and 82–87%, respectively, when grown with 16 rice plants compared with its growth without rice interference. The results suggest that growth and seed production of E. crus-galli can be greatly reduced by increasing rice seeding rate. However, there is a need to involve other weed management strategies to achieve complete control of E. crus-galli and other weed species.     

加工过程对茶叶铅和铜污染的影响

研究了初制加工对茶叶铅和铜污染的影响。结果表明,茶叶加工是铅和铜污染的重要途径之一,但污染的程度因工序、作业方式和机具的金属组分不同而异。初制加工的各个工序都有可能使茶叶铅和铜含量提高,其中铜增幅最大的工序是揉捻,铅增幅最大的工序是摊放;随着揉捻压力增大、时间延长,茶叶铜和铅含量逐渐提高。由于加工方式,特别是揉捻的时间和压力不同,导致不同茶类有明显的区别,烘青和炒青的污染程度较重,红碎茶和工夫红茶次之,龙井茶几乎没有污染。茶叶加工过程中铅和铜污染的来源不同,铜主要来自铜质揉捻机,该工序污染的铜约占茶叶加工铜污染总量的90%以上;铅的污染则主要来自尘土,其次是揉捻机中的铅,摊放在不清洁的地上会导致茶叶铅含量成倍提高。因此,保持加工场所的清洁卫生和调整揉捻机揉筒和揉盘的金属组成是降低茶叶加工过程中铅和铜污染的有效途径。另外,对初制加工的茶叶,清除其中的黄片和茶末对于降低茶叶铅含量也具有重要的作用。