生物有机无机复混肥的养分释放特征研究

通过好气培养间歇淋洗法和室内培养法,研究了生物有机无机复混肥的养分释放和氮素在土壤中的矿化规律。结果表明,生物有机无机复混肥的氮磷钾淋洗累积量呈现"S"型曲线,氮素淋洗释放量在第21 d达到最高峰,磷素在第28 d养分释放量达到高峰,钾素在28~35 d出现养分释放高峰,养分释放更加平缓;氮素在土壤中矿化率2.8%~3.2%,0~18 d表现为净固定过程,18 d以后开始矿化释放无机氮,第35 d达到高峰,硝化作用进行比较缓慢,硝化率表现为前期弱,后期强。     

包膜及其与生化抑制剂结合型尿素在草甸棕壤中尿素态氮溶出特征

在室内恒温培养条件下,以日本70 d聚烯烃包膜尿素和大颗粒尿素为对照,研究4种丙烯酸树脂（MMA）包膜及其与生化抑制剂结合尿素肥料在土壤中尿素态氮溶出与水解特征,以确定不同种MMA包膜尿素在土壤中缓/控释效果与尿素转化机理。结果表明,4种MMA包膜尿素在土壤中尿素累积溶出量在48 d后达到最大值,接近100%,尿素态氮累积溶出80％的时间分别在第24和28 d,时段平均溶出率最高峰值均出现在9～12 d,为7.73%/d～8.04%/d。4种MMA包膜肥料尿素态氮在土壤中累积残留量高峰值分别出现在20和24 d。MMA膜和NBPT共同作用对抑制尿素释放作用效果十分显著, 其结合型肥料对抑制尿素释放作用最强。     

生物炭与叶面硒肥联合施用对生菜吸收镉及土壤镉形态的影响

  目的  为探明生菜吸收富集镉的能力对生物炭与叶面硒肥的响应程度,抑制有毒有害元素镉的吸收。  方法  通过盆栽试验,以生菜为研究对象,在镉污染土壤中添加生物炭,并在生菜叶片上喷硒处理,探索了生物炭与叶面喷硒的联合施用对镉污染土壤理化指标（pH和有机碳）和土壤不同形态镉含量以及对生菜镉吸收累积的影响。  结果  ① 土壤中添加生物炭与叶面硒肥都可以有效降低生菜可食部镉含量,其中喷施低浓度硒的效果更好。当生物炭添加量为30 g kg?1,叶面喷硒浓度为1 mg L?1时,生菜地上部镉含量由0.314 mg kg?1降至0.049 mg kg?1,低于国家食品安全标准（GB 2762—2017）中规定的叶菜类镉限量值0.20 mg kg?1。② 镉胁迫下,添加生物炭与叶面硒肥的交互作用对生菜镉含量和镉富集与转运能力均产生了显著性的影响,相对于生菜根部镉含量,添加生物炭的效应高于叶面硒肥的效应,而对于地上部镉含量,叶面硒肥的效应高于添加生物炭的效应。③ 生物炭添加可通过改善土壤pH和有机碳含量降低酸可提取态、可还原态、可氧化态镉的比例,增加残渣态镉的比例,从而有效地降低生菜对土壤中镉的吸收累积,减少生菜中镉含量。  结论  综合来看,生物炭与叶面硒肥联合施用可以降低生菜镉含量,其效果明显高于两者单独施用的效果,为无公害蔬菜的种植提供理论指导。     

生物炭对复合污染土壤—作物中镉砷累积和转运的影响

针对镉砷复合污染土壤中小麦籽粒重金属积累问题,采用生物模拟方法,以镉砷复合污染区土壤为研究对象,探究杏核生物炭(C1和C2分别表示3%和6%生物炭添加量)对复合污染土壤—小麦/玉米系统中镉砷累积和转运的影响。结果表明:添加生物炭(C1、C2)显著降低了小麦季根际/非根际土壤Cd、As有效性,并且小麦籽粒中Cd、As含量分别比CK平均降低19.25%和50.70%,但前者差异不显著。对玉米而言,生物炭C1、C2处理显著降低穗中Cd和As含量,降幅分别为85.67%,61.28%和98.36%,96.48%;此外,施用生物炭显著降低了小麦—玉米体系中镉砷的转运和累积,但对小麦镉由秸秆向籽粒转运及籽粒中镉累积的影响未达显著水平。总之,添加3%生物炭可降低小麦籽粒和玉米穗中镉、砷含量,且对玉米穗中重金属镉、砷降低效果更明显,综合分析生物炭对镉、砷在复合污染石灰性土壤—小麦/玉米体系中迁移和累积的阻控效应,推荐施用3%生物炭为宜。     

三种不同绿肥的腐解和养分释放特征研究

利用网袋法模拟研究旱地条件下箭筈豌豆（Vicia sativas L.）、苕子（Vicia villosa Roth. Var.）、山黧豆（Lathyrus palustris L. Var. Pilosus ledeb） 三种绿肥的腐解和养分释放特征。结果表明,三种绿肥均在翻压15 d内腐解较快,腐解率均在50%以上,之后腐解速率逐渐减慢,翻压70 d时,箭筈豌豆、苕子和山黧豆的累积腐解率分别达71.7%、67.3%和74.1%。氮和钾在翻压10 d内释放较快,碳和磷在翻压15 d内释放较快,之后释放速率均减慢。箭筈豌豆、苕子和山黧豆在翻压70 d时的碳累积释放率分别为71.3%、67.0%和74.1%。三种绿肥的养分累积释放率均是K>P>N,在翻压70 d时钾的累积释放率均在90%以上,磷的累积释放率为73.3%～78.7%,氮的累积释放率为59.9%～71.2%,其中山黧豆的氮和磷累积释放率高于箭筈豌豆和苕子,而三种绿肥钾的累积释放率无显著差异。养分释放量结果表明,箭筈豌豆和苕子的养分累积释放量表现为K>N>P,而山黧豆表现为N>K>P,不同绿肥的养分累积释放量不同,山黧豆的氮累积释放量最高,箭筈豌豆的磷和钾累积释放量最高,苕子各养分的累积释放量都最低。     

适宜电子束辐照延长醉泥螺货架期及蛋白质保持

为探明电子束辐照对醉泥螺的杀菌效果及辐照后醉泥螺感官品质与蛋白质营养价值的变化,为生食醉泥螺的辐照保鲜应用提供理论依据。以生食醉泥螺为研究材料,研究不同剂量电子束辐照对醉泥螺菌落总数、感官评分、蛋白质含量及其氨基酸组成的影响,并分析辐照后醉泥螺在冷藏和常温贮藏条件下的货架期变化。结果表明：1）经1～9 kGy剂量电子束辐照,醉泥螺的色泽和形态几乎没有变化,但7、9 kGy剂量组醉泥螺产生异味;2）辐照剂量越高,杀菌效果越好,当醉泥螺的初始菌落总数为1200 cfu/g时,菌落总数降至初始值10%所需的辐照剂量D10为3.46 kGy;3和5 kGy剂量的辐照对醉泥螺的抑菌效果明显,无论是冷藏还是常温贮藏,360 d内菌落总数均未超过5000 cfu/g;3）辐照对醉泥螺蛋白质含量无明显影响(P?0.05),不改变醉泥螺的限制性氨基酸种类,但经1、3、5 kGy辐照后,氨基酸总量、必需氨基酸总量及各必需氨基酸的氨基酸评分增加;4）结合电子束辐照对醉泥螺菌落总数及感官评分的影响,辐照剂量以3 kGy为宜,醉泥螺保质期冷藏条件下由对照组的5个月延长至12个月,常温条件下由对照组的不到1个月延长到3个月。该结果能为电子束辐照保鲜醉泥螺提供依据。     

控释肥在宁夏灌淤土中的氮素释放特征研究

为了寻求改善宁夏灌淤土水稻氮素利用的有效措施,通过静水浸泡与盆栽试验,以自研聚氨酯包膜控释肥为研究对象,研究了3种控释肥的氮素释放特征,在氮磷钾等养分供应下研究了5个施肥处理对水稻产量与氮素吸收利用的影响。结果表明:自研控释肥CRF1、CRF2在静水(25℃)中的氮素累积释放比例的动态变化趋势基本一致,都呈"抛物线"形状,其24 h初期释放率分别为3.54%、2.28%(≤15%),28 d的氮素累积释放率分别为33.17%、30.58%(≤80%),符合缓释肥料的国家标准要求。与等量NPK处理相比,CRF2处理主要通过提高水稻穗粒数与千粒重获得最高子粒产量,达到31.21 g/盆,增加了10.44%;其地上部总吸氮量达到150.89 kg/hm~2,提高了10.46%;其氮肥利用率达到36.64%,提高了5.49个百分点。不同施肥处理下土壤铵态氮、硝态氮与无机氮含量峰值均出现在水稻插秧后的15 d前后,随后不同程度的下降,控释肥处理下降较慢,在土壤中氮素释放时间达到75 d以上。其中CRF2处理由于添加了硝化抑制剂双氰胺,能够在水稻移栽45 d前保持最高的硝态氮(第45 d:99.41 mg/kg)和无机氮含量(第45 d:104.46 mg/kg),在60 d前保持最高的铵态氮含量(第60 d:4.03 mg/kg),满足了水稻生育关键期对氮素的需求,从而保证稻谷产量。     

油菜秸秆、紫云英绿肥及其不同比例配施还田的腐解及养分释放规律研究

试验以油菜秸秆和紫云英(Astragalus sinicus L.)为研究材料,通过盆栽模拟稻田条件,研究了油菜秸秆、紫云英绿肥及其不同比例混合处理腐解及养分释放动态。结果表明,腐解过程均呈现出前10~20 d分解较快,后期分解较慢并逐渐趋于平稳的规律。不同处理各养分的释放快慢不同,表现为钾磷氮碳,在翻压90d时钾的累积释放率为95.09%~97.17%,磷的累积释放率为62.65%~87.14%,氮的累积释放率为70%~76.48%,碳的累积释放率为39.53%~64.69%。翻压90 d后紫云英腐解率达到60.07%,油菜秸秆仅40.8%,混合紫云英后,混合处理的腐解程度加快,且腐解程度随紫云英量的增加而增加。     

落干过程对土壤-水稻系统镉和砷形态及有效性的影响

通过盆栽试验,在水稻分蘖盛期土壤水分落干过程的第0、3、5、7天进行连续性取样,研究干湿交替的落干（“氧化”）过程中镉、砷在土壤-水稻系统中的迁移转化动态规律。结果表明：落干过程中水稻各部位镉含量随着落干天数的延长而增加,落干后第5天水稻根内和茎叶镉含量较落干0 d处理分别提高了109%和183%(P<0.05);而水稻根内砷含量随着落干天数的延长先减少后增加,与落干0d处理相比,落干后第3天减少了41.96mg·kg–1(P<0.05);茎叶砷含量则随着落干天数的延长而降低,落干后第5天和第7天茎叶砷含量较落干0 d处理分别减少了12%和18%(P<0.05)。落干后第5天处理根表铁膜镉、砷和铁含量分别较落干0 d提高了97%、16%和16%(P<0.05)。随着土壤含水量的降低,土壤Eh逐渐升高、pH逐渐降低、土壤可溶性有机碳增高和有效铁含量降低,促进了土壤中残渣态镉向酸提取态和可还原态镉转化,有效态镉（DTPA法）含量升高,土壤中砷向可氧化态转化,降低有效砷的含量。通过拟合分析可知,当土壤含水率为33.6%左右时,生物可利用的镉和砷含量可同步保持在相对较低...     

秸秆颗粒化还田加速腐解速率提高培肥效果

为了探索将玉米秸秆压缩成颗粒后还田培肥土壤的可行性,研创新型秸秆还田方式,采用尼龙网袋埋藏法,研究秸秆颗粒化还田与常规粉碎秸秆还田(对照)在盆栽培养条件下的腐解与养分释放特征,以及对土壤呼吸的影响。结果表明,相同质量的秸秆颗粒化后其堆积密度为对照的4.8倍,可显著改善其还田性,提高土壤消纳秸秆的能力。秸秆颗粒化后还田可显著提升秸秆的腐解速率,培养期内前60 d,秸秆颗粒平均腐解速率比对照提升31.68%;培养300 d后,其累积腐解率达80.81%,比对照高出8.7个百分点;估算可比对照提前30 d腐解超过50%,提前14 d完全腐解。秸秆颗粒化还田可显著提升秸秆养分释放速率,培养期前60 d尤为明显;培养300 d后,秸秆颗粒的碳(C,carbon)和氮(N,nitrogen)累积释放率比对照分别提高了11.0和13.2个百分点,但磷素(P,phosphorus)和钾(K,kalium)累积释放率与对照无显著差异(P0.05);估算C、N、P、K养分分别释放超过50%的时间比对照提前15~125 d,提前9 d释放全部养分。此外,秸秆颗粒化还田在培养期前260 d可显著提高土壤呼吸速率,培养期间平均土壤呼吸速率比对照提高18.03%。因此,秸秆颗粒化还田可实现高效快速的培肥土壤,在农业生产中具有较高的推广应用价值。     

Evaluation of Cadmium Toxicity on Survival, Accumulation and Depuration in an Intertidal Gastropod, Turbo Intercostalis

The effect of cadmium on tolerance, accumulation and depurationwas studied in an intertidal gastropod, Turbo intercostalis. Initially, the LC₅₀ value for 96 hr wasdetermined by exposing the snails to different concentrations ofcadmium (2.5 to 12.5 ppm) and it was observed to be 6.18 mg L^-1. Further, the accumulation and depuration of cadmium was investigated in different tissues namely GDG (Gonad-digestive gland) complex, mantle and foot of T. intercostalis on exposure to a sublethal concentration (1.24 mgL^-1) for a period of 20 days. The accumulation of cadmium was found to be more in mantle and GDG complex and less in footduring this exposure and the tissue accumulation was in the order of GDG complex > mantle > foot. The GDG complex was largely responsible for most of the body burden of the metal. The percent body burden of the cadmium exhibited an increasingtrend with exposure time in GDG complex while in mantle therewas a decreasing trend. The foot tissue was observed to have aless percentage of body burden of cadmium. The fractional retention coefficients were also calculated and they showed a gradual increase with exposure time indicating more retention of metal in the tissues. However, depuration of the metal followed a similar trend of increase in all the tissues. The data suggestthat T. intercostalis have a good capacity ofaccumulation and depuration of heavy metal and it may be considered as a suitable species for biological monitoring of the coastal environment.     

稻米镉关键积累时期研究

探明水稻不同生育期镉积累特征对于稻米安全生产具有重要的科学价值与现实意义,本研究采用水培试验方法,于水稻不同生育期分阶段添加外源镉,分析水稻不同生育期低浓度镉(50μg·L~(-1))胁迫下水稻每个生育期、主要部位镉含量及其内在关联。抽穗期阶段镉胁迫对水稻籽粒镉积累速率影响最为明显,最高达到3.41μg·蔸~(-1)·d~(-1)。孕穗期和抽穗期阶段镉胁迫对稻米镉积累量贡献率较高,中嘉早17号分别为40.51%、31.66%,湘晚籼13号分别为37.97%、35.46%。研究表明,孕穗期、抽穗期是控制镉米形成的关键时期,本结果可为镉超标稻田的安全生产及阻控米镉积累提供支持和科学指导。     

Effect of cadmium on life-history parameters in Dendrobaena octaedra (Lumbricidae: Oligochaeta) populations originating from forests differently polluted with heavy metals

This study examined whether earthworm (Dendrobaena octaedra) populations originating from three differently polluted mixed oak-pine forests differ in life history parameters, and whether any observed differences are adaptive. Three forests were chosen: the most polluted forest, near Olkusz, affected by a zinc smelter and on soil containing metal ore; the Niepo?omice Forest, moderately polluted by industry; and the relatively unpolluted Kampinoska Forest. Parent animals (P generation) were collected from each forest and thereafter cultured in the laboratory. From cocoons laid in the laboratory the F1 generation was reared and observed to determine whether it inherited features observed in the parent generation. To distinguish the effect of the metal studied (Cd) from that of soil edaphic conditions, individuals collected in the field were divided into two groups: one cultured in unpolluted medium, the other in medium spiked with cadmium. Earthworms originating from polluted forests (parent generation) exhibited higher cadmium storage capacity, and a higher cadmium concentration factor (cadmium in animal/cadmium in soil). No interpopulation differences in cadmium accumulation were found in their offspring (F1 generation), meaning that the cadmium accumulation ability was acclimatory and not adaptive. Cadmium in low doses negatively affected reproduction parameters: cocoon production, mass of produced cocoons, and reproductive allocation (weight of offspring divided by the weight of adults). The effect of cadmium was stronger in animals originating from the unpolluted forest than in those from the heavily polluted forest. F1 animals originating from the heavily polluted forest exhibited the highest cadmium tolerance (higher mean survival time and median survival time, lower hazard rate probability per time unit that an individual surviving to the beginning of a given interval will die within that interval). The observed tolerance to cadmium (higher reproduction, better survival) in the population from the heavily polluted forest apparently was heritable, suggesting adaptation of D. octaedra to life in a polluted environment.     

Geochemistry of Tungsten and Arsenic in Aquifer Systems: A Comparative Study of Groundwaters from West Bengal, India, and Nevada, USA

The objective of the current study was to estimate the dose in human tissues after inhalation exposure to airborne particulate matter-bound metals at a landfill site. Field measurements have revealed that the 8-h permissible exposure limit set by the Occupational Safety and Health Administration for particulate matter (PM₁₀) was not exceeded for the working personnel at an outdoor weighing facility in the Akrotiri landfill (Chania, Greece). However, PM₁₀ concentrations were exceeding the EU health protection standards (50 μg/m³). Furthermore, dust emanating from landfill operations contains traces of heavy metals due to the nature of materials (e.g., sludge, batteries) which have been deposited over the lifetime of the landfill. In addition, particulate matter-bound metals concentrations at the landfill are enhanced by refuse truck emissions (e.g., exhaust, tire wear dust, brake wear dust, road surface wear dust and resuspension of deposited PM on a road surface) and resuspension from the surface of the composting site. Estimations of particle-bound metals dose in the human body were performed for arsenite (AS^III), lead (Pb) and cadmium (Cd). The Exposure Dose Model (ExDoM) in conjunction with a Physiologically Based PharmacoKinetic (PBPK) model was applied to determine the dose for an adult Caucasian male worker. The ExDoM was used to estimate the human exposure and the deposition, dose, clearance, retention of particulate matter-bound metals in the human respiratory tract and the mass transferred to the gastrointestinal tract and blood. The PBPK model was developed to describe the movement of metals from the blood into the tissues as a blood-flow-limited model. The results showed that after 1 day of exposure to PM_AsIII, the major accumulation occurs in the lung, muscle and liver. In addition, for PM_Pb, the major accumulation occurs in the bone, blood and muscle whereas as regard PM_Cd the major accumulation occurs in the other tissues (the rest of the body), kidney and liver. The results indicate an increased health risk for an adult Caucasian male worker at the landfill site due to exposure to elevated particulate matter concentrations and their associated metallic content.     

Uptake,Storage and Loss of Cadmium and Lead in the Woodlouse Porcellio scaber (Crustacea,Isopoda)

The dynamics of lead (Pb) and cadmium (Cd) accumulation in juvenile Porcellio scaber were studied over 6 months after exposing them to three different concentrations of lead and cadmium in their food. Subsequently the ability of P. scaber to eliminate lead and cadmium was studied over two months. Growth was measured to determine whether metal contamination leads to physiological stress in the animals. The accumulation of Pb and Cd in P. scaber shows two different phases. Up to the age of 2–3 months the assimilation exceeds the rate of growth and leads to rapidly increasing concentrations. After 3 months the rate of accumulation is proportional to the rate of growth and the heavy metal concentrations remain on a stabilized level. P. scaber was able to eliminate about 40% of the assimilated lead within 2 weeks but there was no elimination of Cd within 7 weeks. Contaminated P. scaber shows significant growth reduction. The physiological response of P. scaber to heavy metal contamination is discussed.     

水稻镉吸收与转运机理的研究进展

长期食用含镉（Cd）的大米会引起一系列的疾病，严重危害人体健康，因此控制稻米镉含量对粮食安全具有重要意义。本文从根部镉吸收、根向茎叶的转运和茎叶向籽粒转运三个角度系统总结，从生理角度综述了这三个重要过程涉及的生理机制，从分子生物学角度总结了相关基因的分子调控机制，归纳并讨论了一些存在争议的问题。深度探讨了调控吸收、转运和籽粒积累这三个过程来降低稻米镉含量的有效措施，分析其原理及实用价值。提出了选育镉低积累品种为最根本最有力的镉污染治理措施，为明确水稻镉污染治理方向提供重要的参考。     

Assessment of heavy metal uptake and translocation in Dyera costulata for phytoremediation of cadmium contaminated soil

Abstract

Heavy metal pollution is a widespread global problem causing serious environmental concern. Cadmium, one of the heavy metals, is water soluble and can be transferred from soil to plants and enter into the food chain. It is detrimental to human health because it accumulates in the body and can cause renal tubular dysfunction, pulmonary emphysema and osteoporosis. This heavy metal needs to be cleaned up for a clean and safe environment. An experiment was conducted to evaluate the potential of Dyera costulata as a phytoremediator to absorb cadmium from contaminated soils. Dyera costulata seedlings were planted on six different growth media (soil + different levels of cadmium): Control, 25 ppm Cd, 50 ppm Cd, 75 ppm Cd, 100 ppm Cd and 150 ppm Cd. The highest growth performance mainly height, basal diameter and number of leaves were in the control, 50 ppm Cd and 25 ppm Cd treatments, respectively. The highest accumulation of cadmium (52.9 ppm) was in the 75 ppm Cd treatment. Among the plant parts, leaves showed the highest concentration of cadmium. Dyera costulata showed high translocation factor and low bioconcentration factor values in soil at high cadmium concentrations and was also able to tolerate and accumulate high concentrations of cadmium. The roots of Dyera costulata were found to be suitable for the absorption of cadmium in contaminated soils. This species can be an efficient phytoremediator for soils contaminated with cadmium.     

品种和土壤对水稻镉吸收的影响及镉生物有效性预测模型研究进展

稻田受重金属镉(Cd)污染后,土壤中的Cd可能被植物吸收通过食物链进入人体,威胁人类健康。而水稻品种和土壤类型对Cd吸收和积累有着深远的影响,因此在进行Cd的农产品安全阈值制定和人体健康风险评价时,需考虑土壤Cd的生物有效性和不同水稻品种对Cd吸收的影响。本文综述了水稻品种和土壤类型对Cd吸收和积累的影响,并重点介绍了目前常用于预测重金属生物有效性的模型,以期为环境风险评价、土壤环境质量标准及农产品安全阈值制定提供有效的工具,并为生产安全(无公害)稻米提供参考。     

浙西石灰岩地区土壤和稻米镉含量研究

为理解石灰岩地区农田土壤重金属积累特点及污染风险,以浙西石灰岩地区为例,随机选择了153块重金属污染农田,点对点采集了土壤和水稻样品,分析了土壤和糙米中镉的含量及土壤性状,探讨了石灰岩地区污染农田土壤与稻米镉积累特点及其与土壤性状的关系。结果表明,土壤全镉随粘粒含量的增加而增加,随土壤pH的下降而下降;土壤有效镉占全镉的比例与土壤pH呈负相关,糙米中镉含量与土壤有效镉、水溶性镉呈显著正相关;糙米中镉含量与土壤pH、有机质含量及粘粒含量均呈现显著负相关,土壤pH是影响石灰岩地区农田糙米镉积累最为重要的因素。《土壤环境质量－农用地土壤污染风险管控标准（试行）》（GB 15618—2018）的污染风险筛选值并不适用于石灰岩地区高pH的土壤。当6.5 < pH ≤ 7.5时,土壤重金属镉含量与农产品中重金属镉超标结果并不一致,其风险筛选值（0.60 mg kg?1）偏低,实际的风险筛选值可能在0.80 mg kg?1以上。土壤水溶性镉较土壤全镉和有效镉能更好地评估石灰岩地区农作物重金属镉的污染风险。