生物炭修复重金属污染农田土壤的机制及应用研究进展

将生物质转化为生物炭并用于重金属污染农田土壤修复中,是有效利用生物质资源、保障粮食安全的有效途径之一。然而,生物炭的应用效率受其特性和土壤环境影响极大。该研究综述了生物炭特性,并探讨了生物质和热解温度对其影响规律,阐明了生物炭对重金属的直接固定作用,以及通过影响土壤p H值、阳离子交换量(Cation Exchange Capacity,CEC)、矿物组分和有机质等,进而间接固定重金属的作用机制。同时,该文系统总结了国内外生物炭在田间试验中的应用,从土壤重金属迁移性和生物有效性、作物累积重金属和作物产量等3个方面阐明了生物炭的应用效果和作用规律。针对田间试验条件区别于室内试验的特殊性,探讨了生物炭施撒方式及用量、施肥等田间管理和气候环境等现场条件对生物炭应用的影响,并对今后完善生物炭在土壤修复中作用机制、扩大研究尺度和长期土壤监测等方面研究进行了展望。     

生物炭研究进展及其研究方向

近几年来,随着巴西亚马逊流域考古发现黑土(black earths,或terra preta de indio(葡萄牙语))及研究的深入,认为将生物质炭化还田不仅能藏碳于土,减缓全球气候变化,而且能提高全球粮食安全保障.生物质在无氧或低氧条件下高温裂解炭化而成的产物被称为生物炭(biochar).本文将从生物炭特性;生物炭对作物产量和养分吸收的影响;生物炭分解和对土壤碳周转的影响以及对污染物降解和生物有效性影响方面进行综述,以期为国内生物炭研究提供参考.     

生物炭对土壤肥力与环境质量的影响机制与风险解析

生物炭作为土壤改良剂和促进作物生长的应用价值已经被很多研究证实。该文综述了生物炭在改善农业土壤质量和作物生长中的应用研究进展,系统阐述了生物炭在提高农业土壤有效水含量,增加土壤矿质元素利用效率,缓解土壤酸化,降低土壤重金属生物有效性和提高农作物产量与质量方面的重要作用与微观机制。特别地,该文强调了生物炭应用于农业生态系统过程中可能引起的多环芳烃、重金属等污染物富集以及氮素根系吸收量下降等不可忽视的潜在问题,并对今后的重点研究方向进行了系统分析总结,以期为生物炭在提高土壤肥力质量与环境质量中的安全与高效利用提供科学参考。     

生物炭及炭基硝酸铵肥料对土壤化学性质及作物产量的影响

为了促进生物炭研究和农用,采用盆栽试验研究了两种生物炭基氮肥及相应生物炭对土壤部分化学性质、养分状况及作物产量的影响。试验结果表明：施用生物炭基氮肥可显著提高土壤有机碳含量,提高土壤pH值、阳离子交换量、土壤速效磷、速效钾和矿质态氮含量,增强土壤保肥能力,促进作物增产。生物炭对土壤化学性质和养分状况虽有一定改善作用,但作物增产效应不明显甚至减产。因此,将生物炭与肥料复合制成生物炭基肥料不但可以保持生物炭改良土壤的功能,还可促进作物生长和增产,有利于生物炭农用效益的提升。     

水洗生物炭对2种类型土壤钾素淋失的影响

为了探究生物炭对潮土和砂土钾素淋失的调控效应,通过土柱淋溶模拟试验,以水洗生物炭为研究对象,比较生物炭水洗前后不同形态钾含量、表面形貌和含氧官能团变化,进而探究不同用量水洗生物炭对2种类型土壤钾素淋失的阻控效应。结果表明:水洗处理可使生物炭水溶性钾含量由13.9 g/kg降至0.06 g/kg,而对生物炭孔隙结构和表面含氧官能团影响较小。水洗生物炭对潮土和砂土水分淋失的影响受其施用量的影响,表现为低量促进、高量抑制的趋势,添加1%水洗生物炭显著增加了2种类型土壤水分淋失总量。生物炭对2种类型土壤钾素淋失的影响各异,添加2%和4%水洗生物炭对砂土钾素淋失表现出显著的阻控效应(P0.05),钾素淋失量分别较不加生物炭处理降低了21.2%和28.3%,而添加1%水洗生物炭却增加了潮土钾素淋失量(P0.05)。另外,生物炭可提升土壤阳离子交换量和表层土交换性钾含量,且提升幅度随生物炭施用量的增加而增加,并且对砂土的提升效果更明显。因此,从钾素淋失角度考虑,生物炭更适用于阳离子交换量较低、保肥能力差的砂质土壤上。     

施用生物炭对农田生态系统影响的研究进展

从施用生物炭对土壤理化性状、土壤生物、土壤碳截留、作物产量、温室气体排放的影响等方面,总结分析了施用生物炭对农田生态系统的影响。结果表明,施用生物炭能够改善土壤理化特性和微生物生境,提高养分利用率,但对作物的增产效应具有一定的不确定性。生物炭的稳定性对增加农田土壤碳截留有重要作用,其降解过程目前尚不清楚。添加生物炭影响土壤有机质分解即激发效应,但激发效应的方向和幅度的变异较大。在影响温室气体排放方面,施用生物炭能有效减少N2O排放,但对CO2和CH4的减排效应具有较大的不确定性,生物炭的性质、施用量、土壤类型和肥力状况等因素是导致这些不确定性的主要原因,今后应综合考虑以上因素开展长期定位试验,客观评价生物炭对农田生态系统功能的影响和作用。     

生物炭基肥在我国的制备和应用研究进展

生物炭基肥是实现农作物秸秆资源化利用的一种绿色肥料,因其在农业生产中能够显著提高作物产量和品质而受到广泛关注.然而,生物炭基肥的制备过程影响生物炭基肥的缓释、成型和其他功能性效果,进而对作物产量和品质产生的影响缺乏系统而全面的报道.从生物炭原料、炭肥比、制备方法和制备工艺改性研究4部分阐述了生物炭基肥的制备过程对生物炭...     

土壤属性和作物生长对生物炭施用的响应和反馈研究进展

生物炭作为一种土壤改良剂,近年来在提升土壤质量和作物产量方面效应良好。在全面梳理生物炭施用效果方面的最新研究基础上,总结了土壤理化性质、作物生长和产量对生物炭施用的响应和反馈规律。结果表明:(1)生物炭的来源、是否酸化、施用年限及施用量决定了施用后的土壤属性及作物产量变化幅度。一般来说,施用量增加、土壤容重降低,土壤孔隙度增加、土壤水力性质及入渗性能改善,土壤温度也增加。(2)由于土壤物理性质改变,施用生物炭最终降低了土壤表层的盐分表聚。生物炭对土壤pH的调节效果取决于两者pH的差异。此外,随着生物炭施用量增加,有机质含量呈线性增加趋势,而有效氮、有效钾和有效磷呈先增加后减小的趋势。(3)适宜施用生物炭使作物长势更好、产量更高;而过高的施量既不经济、增加成本,又对作物产量提升无益,适宜生物炭施用量为10~40 t/hm²。(4)总体上,虽然土壤属性和作物生长对生物炭施用的响应和反馈因试验条件、土壤质地和作物类型、气候条件差异而表现出响应幅度不同,但大部分结果证实,土壤属性和作物生长对生物炭施用具有正面响应。今后在生物炭施用的科学认识和生产实践中需因地制宜制定施用策略。     

生物炭在土壤改良和重金属污染治理中的应用

作为重要的土壤改良剂、污染物质吸附剂的生物炭在农业和环境中具有巨大的应用价值和现实意义,因而受到国内外学者们的普遍关注。本文基于生物炭在农业增产和重金属污染治理方面的国内外研究文献,综述了生物炭的基本特性及对土壤的改良作用,分析了生物炭对土壤肥力及作物增产的影响,阐述了生物炭对土壤重金属污染修复机理,及该领域未来的发展动向,以期为生物炭大规模农用提供参考。     

添加生物炭对黄绵土耕层土壤可蚀性的影响

生物炭因其固有的特性和理化性质成为新兴的土壤结构改良添加剂,目前大多研究集中在添加生物炭后土壤理化性质及作物产量变化方面,而对添加生物炭后土壤抗侵蚀效应变化的研究很少。以黄土高原典型黄绵土为例,采用室内人工模拟降雨试验,研究添加不同含量(0%、1%、3%、5%、7%)和粒级(2mm、1mm、0.25mm)的生物炭对坡面片蚀的影响。结果表明:(1)生物炭含量、生物炭含量与粒级的交互作用对降雨侵蚀有显著影响,生物炭粒级对侵蚀的影响效应相对较弱。(2)各次降雨中,添加1%含量的各粒级生物炭均可产生减流减沙作用,探讨其他含量的生物炭对侵蚀和径流的影响时需结合生物炭的粒级进行具体分析。(3)产流时间随生物炭含量的增加而减小,且≤3%的生物炭添加量可延迟产流时间。     

How good is the evidence that soil‐applied biochar improves water‐holding capacity?

Biochar application to soil is suggested as a way of enhancing soil fertility by increasing the availability of nutrients and water. The former is perhaps better documented while the latter has less experimental support. This review critically investigates the recent literature which focuses on determining whether biochar induces increases in plant available water and that this provides part of the explanation for possible increases in crop yield. A number of studies suggest that biochar increases crop yields, and this is linked to the enhancement of soil water content and increased crop growth. However, many of these studies fail to fully consider if the measured biochar increases of 10–30% in soil water content were actually responsible for an increase in plant available water for crop growth. There is also limited evidence of increased crop yields when biochar is used in field experiments. While biochar soil application may increase soil water content, this appears to most likely occur with free draining coarsely textured sandy soils. As yet there is limited evidence that biochar improves soil water content in temperate soils and even less that it facilitates plant tolerance to drought stress. More recent literature shows the use of methods which quantify soil biochar changes with respect to plant water availability. However, despite some advances in our understanding of biochar's mode of action, there are still only a few studies which link increases in plant available water with increased crop yields, and particularly with respect to the longer term use and functionality of soil‐applied biochar.     

Biochar combined with nitrogen fertilizer affects soil properties and wheat yield in medium-low-yield farmland

Biochar combined with fertilizer as a soil amendment benefits to improving soil fertility, especially soil organic carbon and crop yield. However, the effect of biochar on the improvement of soil properties and crop yield was varied from soil properties and limited for medium–low-yield farmland in the North China. During the completely randomized field experiment, SIX treatments (biochar applied as 0, 15 and 30 t·ha^-1, under 240 and 300 kg N ha^-1 nitrogen fertilizer) were applied in wheat season and examined to reveal changes in the SOC and other properties of 0- to 10-cm and 10- to 20-cm soil layers. The results showed that two years after the application of biochar, a significant increase in the SOC was observed, ranging from 19.52% to 97.50% (p < 0.05) in the 0- to 20-cm soil layer. Wheat yield and SOC content increased with increasing amount of biochar applied under the same amount of nitrogen fertilizer. The content of soil available potassium increased significantly under 30 t·ha^-1 biochar application (p < 0.05). Both biochar and nitrogen fertilizer application could increase wheat yield, and the effect of biochar application for increasing wheat yield was better than that of nitrogen fertilizer. Wheat yield and SOC content increased with increasing nitrogen fertilizer at the same amount of biochar application. The principal component analysis results showed that biochar input, SOC, available potassium and total nitrogen were the key factors affecting wheat yield. Biochar application is a fast and effective measure to improve SOC and wheat yield in medium- and low-yield farmlands.     

Responses of soil microbial communities to manure and biochar in wheat cultivation of a rice-wheat rotation agroecosystem in East China

Soil contamination in agroecosystems remains a global environmental problem. Biochar has been suggested as an organic amendment to alleviate soil pollution, sequester carbon (C), and improve soil fertility. However, information on how bacterial and fungal communities in acidic bulk and rhizosphere soils respond to swine manure and its biochar is still lacking. In this study, biochar and swine manure were applied at two rates of 1.5 and 3 t ha^-1 in a rice-wheat rotation field to assess how soil characteristics, especially pH and chemical element availability, correlate to compositional variations of bacteria and fungi in bulk and rhizosphere soils. Our results showed that high rates of biochar and manure promoted the bacterial richness in bulk and rhizosphere soils by increasing soil pH and reducing soil arsenic (As) and copper (Cu) availability. Compared with soil As and Cu availability, soil pH had opposite effects on beta diversity of both the bacterial and fungal communities. Specifically, biochar and swine manure applications stimulated the bacterial classes Gemmatimonadetes, Deltaproteobacteria, and Gammaproteobacteria by increasing soil pH and decreasing soil available chemical elements. Opposite trends were observed in fungal communities responding to biochar and manure. For example, biochar restrained the fungal class Eurotiomycetes by decreasing soil As and Cu availability, but manure inhibited Leotiomycetes mainly because of an increase in soil pH and a decrease in soil dissolved organic C. These suggest that both bacterial and fungal communities respond significantly to biochar and manure amendments in both bulk and rhizosphere soils, possibly because of their sensitive adaptation to variations in soil environmental factors, such as pH level and chemical element availability.     

生物炭对不同酸化水平稻田土壤性质和重金属Cu、Cd有效性影响

针对南方稻田土壤酸化严重,导致养分流失有毒重金属活化,严重影响稻米质量安全的重大现实问题。以水稻秸秆和谷壳等农业废弃物为原料制备生物炭(分别记为RSC和RHC),研究不同原料生物炭对酸化土壤改良及其对重金属有效性的影响。设置3个生物炭用量(0,20,50 g/kg,分别记为CK、C1、C2),4种土壤酸化水平(pH 4.01,4.25,4.33,4.58,分别记为L1、L2、L3、L4),生物炭与重金属污染土壤共同培养60天后测定土壤pH、全氮、有机质、有效磷、速效钾和有效态Cu、Cd含量。结果表明:RSC对酸化土壤pH的改良效果明显优于RHC,且施炭量越高提高幅度越大,RSC的C2处理使4种酸度水平的土壤pH分别提高了0.68,0.97,1.29,1.71个单位。2种生物炭均能提高土壤的全氮、有效磷、速效钾和有机质含量,其中各施炭处理有机质显著提高,尤以速效钾的增幅最为显著,RSC对4种养分的提高均优于RHC。RHC对土壤有效态Cu含量无显著影响;RSC的C2较C1处理更能降低土壤中有效态Cu含量,使4种酸度水平的土壤分别降低了13.62%,6.57%,4.36%,7.88%。RHC处理的L3、L4土壤中有效态Cd含量显著降低,最大分别降低了13.79%,19.23%。RSC使4种酸度土壤有效态Cd含量最大分别降低了20.00%,25.81%,20.69%,19.23%。相关分析表明,土壤pH与有效态重金属含量呈显著负相关关系。水稻秸秆炭用于改良酸化土壤、降低重金属Cu和Cd有效性的效果更佳,且降低污染土壤中Cd的有效性较Cu好;生物炭对酸化程度越低的土壤pH和有效磷含量的提高以及有效态Cd含量的降低效果较好,而有效态Cu含量的降低效果则在酸化程度越高的土壤中表现更佳;土壤pH是生物炭调控重金属Cu、Cd有效性的主要影响因素。     

Biochar application to sandy soil: effects of different biochars and N fertilization on crop yields in a 3-year field experiment

During the past years, most biochar studies were carried out on tropical soils whereas perennial field experiments on temperate soils are rare. This study presents a 3-year field experiment regarding the effects of differently produced biochars (pyrolyzed wood, pyrolyzed maize silage, hydrothermal carbonized maize silage) in interaction with digestate incorporation and mineral N fertilizer application on soil C and N, crop yields of winter wheat, winter rye and maize and the quality of winter wheat. Soil C and plant available potassium were found to be significantly positive affected by pyrolyzed wood biochar whereas the latter only in combination with N fertilization. Crop yields of winter wheat, winter rye and maize were not affected by biochar and showed no interaction effects with N fertilizer supply. Wheat grain quality and nutrition contents were significantly affected by biochar application, for example, highest amounts of phosphorus, potassium and magnesium were determined in treatments amended with pyrolyzed maize silage biochar. Biochar induced an improved availability of plant nutrients, which apparently were not yield limiting in our case. These results limit the potentials of biochar for sustainable intensification in agriculture by increasing crop yields for the temperate zones. However, detection of other environmental benefits requires further investigations.     

生物炭对滴灌春小麦产量及土壤肥力的影响

为了解生物炭对滴灌春小麦产量及土壤肥力的影响,通过2年田间试验对灰漠土土壤和春小麦养分及产量等进行了研究。结果表明:与CK相比,施用生物炭显著(P0.05)增加了土壤肥力,并显著(P0.05)增加春小麦对N、P和K的吸收,还对春小麦产量及构成具有积极的促进作用。与NP处理相比,NP+B6处理显著(P0.05)增加了土壤有机质、全氮和速效钾含量以及植株吸磷量。与NP+M6处理相比,NP+B6处理显著(P0.05)增加了土壤全氮、速效钾和植株养分吸收量。     

Effect of Three Different Qualities of Biochar on Selected Soil Properties

An incubation study was conducted to determine how biochar interacts with a nitrogen fertilizer and how it reacts in the soil as well as to measure the effect of different biochars on soil chemical properties. Two Iowa soils, Nicollet surface soil (fine-loamy, mixed, superactive, mesic Aquic Hapludoll) and Storden subsoil (fine-loamy, mixed, superactive, mesic Eutrudept), were mixed with three different qualities of biochar and a nitrogen fertilizer (urea). The biochar was created from corn stover that was pyrolized with three different amounts of atmospheric air: 0% (biochar 1), 10% (biochar 2), and 25% (biochar 3). Soil tests for pH, total nitrogen (N), extractable phosphorus (P), extractable potassium (K), ammonium N, nitrate N, organic matter, and total carbon (C) were performed. The different biochars significantly affected the total N, total organic C, and pH in both soils at all rates of urea applied. The conditions during pyrolysis influenced how the biochar/fertilizer reacted with the soil.     

农田土壤黑碳应用研究进展

在应对全球气候变暖和保障粮食安全的双重背景下,如何增加土壤碳库容量、 提升土壤生产力以及减少环境危害已成为农学家、 土壤学家和环境学家在二十一世纪的研究重点和热点,黑碳（或生物碳）在农田土壤中的应用作为一种增加土壤碳库和提高土地生产力的新方法引起了极大关注。本文综述了黑碳在农业土壤中的含量,应用黑碳（生物碳）对作物产量、 土壤肥力和温室气体排放的影响; 探讨了应用黑碳影响作物生产力和土壤环境行为的机理以及农田土壤应用黑碳在不同区域、 作物类型、 用量和黑碳性质上的差异表现; 展望了农田应用黑碳未来研究的方向和热点。