基于碳足迹和碳承载力的新疆碳安全评价

[目的]探索新疆碳足迹和碳承载力的的变化,评价其碳安全程度,为新疆低碳经济的发展提供理论依据。[方法]利用碳足迹理论对新疆2000—2014年的碳足迹、植被碳承载力、净碳足迹进行计算分析,并利用碳压力指数(CTI)构建了碳安全评价模型。[结果]新疆碳足迹呈上升趋势,从2000年的1.08×108 t上升到2014年的5.04×108 t,其中化石能源碳足迹占总碳足迹的比重达到96%;碳承载力不断增加,草地固碳量所占的比重最大,其次是森林、农田、园地和城市绿地;人均净碳足迹、碳压力指数均呈现增长趋势,导致新疆碳安全程度不断下降,从2009年开始就处于极不安全的状态。[结论]化石能源消费的增加是导致新疆碳足迹升高和碳安全程度下降的主要原因,虽然其能源利用率不断提高,但在未来一段时间仍然面临严峻的生态环境问题。     

上海农田生态系统碳源汇时空格局及其影响因素分析

以1990—2009年上海市农作物产量、农田面积、农业投入等相关统计数据为依据,对上海农田生态系统主要碳源汇进行了测算,分析了上海农田生态系统碳源汇的时空变化特征,并探讨了农田生态系统碳源汇的影响因素。结果表明,1999—2009年上海农田生态系统碳吸收总量总体处于逐步下降趋势,且经济作物和果蔬作物碳吸收比例分别下降和上升明显;碳排放总量则呈逐步下降并趋于稳定的趋势,农用化学品投入是其主要排放源;单位面积碳吸收和排放量则一直处于波动状态。2009年上海各区县农田生态系统碳吸收量、碳排放量和单位耕地面积碳吸收量均为远郊大于近郊,而单位耕地面积碳排放量则为近郊大于远郊。碳源汇影响因素相关性分析表明,碳吸收与粮食作物和经济作物产量显著正相关,而与果蔬作物产量显著负相关;碳排放与农用化学品投入和燃料动力使用以及耕作灌溉管理均显著正相关。     

不同有机物料还田对华北农田土壤固碳的影响及原因分析

中国农业面临着废弃物数量大、污染严重,农田土壤生产力低的现实问题。该研究以增加农田土壤固碳为目标对砂质农田进行有机物料还田,将秸秆、猪粪、沼渣和生物炭4种物料用尿素调节等氮还田,对农田土壤有机碳、颗粒有机碳、可溶性有机碳和微生物量碳的含量进行测定,并探究不同有机物料还田对土壤有机碳的影响原因。研究结果表明:物料还田3a后,生物炭、猪粪和沼渣处理土壤有机碳(SOC)比秸秆处理分别高262.4%、26.8%和20.7%;2014—2015年生物炭处理的土壤微生物量碳(MBC)较秸秆处理降低2.9%~35.5%,猪粪处理和沼渣处理的土壤可溶性有机碳(DOC)分别提高17.1%~60.1%和7.2%~64.8%;2014—2015年生物炭、猪粪和沼渣处理土壤颗粒有机碳(POC)较秸秆处理提高10.8%~148.2%、9.5%~58.3%和11.3%~57.6%;物料还田后,土壤总有机碳(TOC)和POC呈极显著的回归关系(R2=0.67,P0.001),土壤DOC与MBC有极显著相关性(R2=0.52,P0.001)。与秸秆还田相比,生物炭还田有利于土壤POC的累积进而促进土壤有机碳的提升,猪粪和沼渣则通过提高土壤MBC、DOC和POC的含量,促进土壤有机碳的周转和固定。从农田土壤固碳角度而言,生物炭,猪粪和沼渣还田优于秸秆还田。     

Reduced tillage with residue retention improves soil labile carbon pools and carbon lability and management indices in a seven-year trial with wheat-mung bean-rice rotation

Soil total organic carbon (TOC) is a composite indicator of soil quality with implications for crop production and the regulation of soil ecosystem services. Research reports on the dynamics of TOC as a consequence of soil management practices in subtropical climatic conditions, where microbial carbon(C) loss is high, are very limited. The objective of our study was to evaluate the impact of seven years of continuous tillage and residue management on soil TOC dynamics (quantitative and qualitati...     

栓皮栎林与油松林土壤有机碳及其组分的研究

土壤有机碳在可持续森林生产力的维持中起重要作用。本文以北京鹫峰地区栓皮栎林和油松林为研究对象,对土壤有机碳及其组分的含量与密度进行了研究。结果表明,在0~20 cm土层中,栓皮栎林土壤总有机碳、轻组有机碳和易氧化碳的含量分别达到14.05 g kg-1、2.97 g kg-1和0.38 g kg-1,显著高于油松林。栓皮栎林0~20 cm土层内土壤颗粒有机碳、轻组有机碳和易氧化碳密度分别较油松林高39.68%、77.77%、145.45%,两植被类型间的的差异均达到了显著水平。在土壤总有机碳中,颗粒有机碳、轻组有机碳和易氧化碳的分配比例分别为23.60%~41.40%、9.10%~33.33%和1.39%~2.80%。因此,栓皮栎林较油松林更有利于土壤总有机碳和活性有机碳的积累。     

Organic matter availability for denitrification in soils of different textures and drainage classes

Abstract

Soils from the A, B, and C horizons representing three natural drainage classes and differing textures were chosen to study relationships between denitrification rate and estimates of available carbon. The highest correlation with denitrification rate was obtained with total organic C. Water‐extractable C, mineralizable C and 0.1 N Ba(OH)2‐extractable C produced less satisfactory correlations. When soils of the B and C horizons only were included in the regression analysis, 0.1 N Ba(OH)₂‐extractable C was found to be unsatisfactory as a predictor of available C for soil denitrifiers. None of the four methods for estimating available C were found adequate for B and C horizon soils which were relatively low in available C. Coarser‐textured soils with relatively low C levels had correspondingly low denitrification rates. Regressions of denitrification rate on mineralizable C or water‐extractable C were nonsignificant with poorly drained soils whereas they were highly significant with well or imperfectly drained soils.     

长白山森林土壤有机碳库大小及周转研究

主要分析不同森林植被下有机碳的分解动态和土壤碳库各组分大小、周转时间。结果表明：土壤样品培养90天，CO2累计释放量表层大致为1723～5065mg／kg、下层大致为178～642mg／kg。分解速率总的趋势是前期快，后期慢，表层明显大于下层。大小顺序为：冷杉林〉针阔混交林和阔叶林〉针叶林。在不同植被下的表层和下层土壤中，活性碳占总有机碳的0．54％～1．67％，0．45％～5．48％．平均驻留时间为11～56天、60～88天；缓效性碳占总有机碳的23．0％～63．3％，33．2％～72．2％，平均驻留时间为4～70年、24～161年；惰效性碳占总有机碳的35．5％～75．5％．26．0％～65．%。表层土壤的总有机碳、活性碳、缓效性碳和惰效性碳含量都明显大于下层。凋落物的化学组成主要决定活性碳库、缓效性碳库含量，土壤的粘粒含量等性质主要决定惰效性碳库含量。     

不同森林植被下土壤有机碳的分解特征及碳库研究

分析了不同森林植被和同一植被不同林龄的人工杉木林下土壤有机碳的分解特征及土壤有机碳中的活性碳库、缓效性碳库和惰效性碳库的大小和周转时间。结果表明:不同森林植被下土壤有机碳的分解速率不同,总的趋势都是:培养前期分解速度快,后期分解速度慢,土壤剖面A层>剖面B层。在剖面A层中:不同森林植被下分解速率的大小顺序为常绿阔叶林>人工杉木林,不同林龄的人工杉木林为成熟林>中龄林>幼龄林;在剖面B层中:分解速率差异不大。不同森林植被下不同土壤剖面上的土壤活性碳库、缓效性碳库和惰效性碳库的库容和分解速率不同,土壤活性碳库碳含量一般占总有机碳的0 99%～2 89%,田间平均驻留时间为10～23天;土壤缓效性碳一般占总有机碳的17 17%～55 46%,田间平均驻留时间为1 6～24 2年;土壤惰效性碳一般占总有机碳的42 05%～80 66%,田间平均驻留时间为假定的1000年。     

Carbon turnover and sequestration potential of fodder radish cover crop

We studied fodder radish carbon turnover as affected by soil tillage in Foulum, Denmark. Actively growing fodder radish monoliths from direct‐drilled (DD) and conventionally tilled (CT) plots were extracted and labelled regularly with ¹⁴C isotope across their entire growth period. At the end of the fodder radish growth cycle, labelled biomass was harvested and incorporated into the same monolith. These monoliths were destructively sampled at biomass incorporation, 4, 8 and 18 months after incorporation. For each sampling period, soil and root samples were taken at 0‐ to 10‐, 10‐ to 25‐, and 25‐ to 45‐cm‐depth increments for determination of ¹⁴C distribution and retention. Carbon‐14 declined significantly with increasing soil depth at each sampling for the two tillage practices (P < 0.05). We further observed significantly higher ¹⁴C at 0–10 cm for DD than for CT at 4 and 8 months after biomass incorporation. For the 10–25 cm depth, ¹⁴C was significantly higher for CT than for DD, 4 and 8 months after incorporation. However, despite these depth‐specific differences, cumulative (0–45 cm soil depth) ¹⁴C retention was similar for DD and CT treatments for all the sampling periods. On the basis of a CN‐SIM model forecast, we estimated that over a 30‐yr period of continuous autumn fodder radish establishment, at least 4.9 t C/ha fodder radish C with a residence time of more than 20 yr could be stored in the soil.     

2000—2020年陕西省陆地生态系统NPP时空变化与潜力

[目的] 在“双碳”战略实施背景下,准确评估陆地生态系统固碳现状、速率与潜力对实现“碳中和”目标意义重大。陕西省横跨3个气候带,南北气候差异大,植被类型丰富。近年来,由于多项生态工程(退耕还林还草、三北防护林等)的实施,陕西省植被覆盖度进一步提升至60.7%,固碳能力巨大。陆地生态系统NPP(植被净初级生产力)是反映植被固碳能力的重要指标,然而,关于陕西省NPP的时空动态变化,以及NPP未来潜力的空间分布鲜有研究。[方法] 以陕西省陆地生态系统为研究对象,利用CASA模型和邻域相似空间分布法评估陕西省植被NPP及其潜力的时空分布特征。[结果] (1)陕西省植被总固碳量在2000年和2020年分别为687,1 020 Tg,增加333 Tg,增幅为48.5%。(2)陕西省NPP呈南高北低,中间存在最高值或最低值的空间分布态势,平均值在2000年和2020年分别为333.2,494.8 gC/m²,共增加161.6 gC/m²,增加幅度呈北高南低的分布态势。(3)陕西省生态系统NPP的实际最大潜力为2 304 Tg,相比于2020年增加41.3%,空间分布态势表现为由南到北逐渐降低,且空间分布特征均表现高度空间自相关特性,但局部差异较大。[结论] 陕西省植被总固碳量在2000—2020年显著增加,同时,未来植被固碳潜力巨大。评估和预测陕西省区域尺度生态系统NPP时空动态变化及潜力空间分布特征,可为科学评价提升区域碳汇能力提供一定的评价体系和理论参考。     

Managing soils for negative feedback to climate change and positive impact on food and nutritional security

ABSTRACT

The increase in atmospheric concentration of carbon dioxide from 278 ppm in the pre-industrial era to 405 ppm in 2018, along with the enrichment of other greenhouse gases, has already caused a global mean temperature increase of 1°C. Among anthropogenic sources, historic land use and conversion of natural to agricultural eco-systems has and continues to be an importance source. Global depletion of soil organic carbon stock by historic land use and soil degradation is estimated at 133 Pg C. Estimated to 2-m depth, C stock is 2047 Pg for soil organic carbon and 1558 Pg for soil inorganic carbon, with a total of 3605 Pg. Thus, even a small change in soil organic carbon stock can have a strong impact on atmospheric CO₂ concentration. Soil C sink capacity, between 2020 and 2100, with the global adoption of best management practice which creates a positive soil/ecosystem C budget, is estimated at 178 Pg C for soil, 155 Pg C for biomass, and 333 Pg C for the terrestrial biosphere with a total CO₂ drawdown potential of 157 ppm. Important among techniques of soil organic C sequestration are adoption of a system-based conservation agriculture, agroforestry, biochar, and integration of crops with trees and livestock. There is growing interest among policymakers and the private sector regarding the importance of soil C sequestration for adaptation and mitigation of climate change, harnessing of numerous co-benefits, and strengthening of ecosystem services.     

A rapid accurate wet oxidation diffusion procedure for determining organic and inorganic carbon in plant and soil samples

Abstract

A method is presented for determining organic carbon content of soils, extracts and plant tissue utilizing an acidic wet oxidation in modified culture tubes; samples containing carbonates are pretreated with dilute acid. Evolved CO₂ is trapped in a NaOH solution and quantified titrimetrically. The method described has a range of 0.4–11 mg. carbon and the range can be extended in either direction by modifying the CO₂ trapping/titration procedure. This method is as accurate and precise as more time consuming dry oxidation procedures.     

土壤中钙键和铁/铝键结合的有机碳差异的比较

为研究矿质元素在有机碳矿化中所起的作用,以棕壤、黄棕壤、红壤为供试土壤,比较了不同利用方式和施肥处理土壤中钙键、铁/铝键结合的有机碳的差异。结果表明,从北至南的地带性土壤(棕壤、黄棕壤和红壤)系列中,全钙及与有机碳结合的钙依次降低,钙键结合的有机碳占有机碳总量的比值依次升高;铁/铝键结合的有机碳及其占全碳的比值依次升高。与自然土壤相比,耕作土壤在不施肥条件下,钙键有机碳、铁/铝键有机碳占有机碳总量的比值增加,且铁/铝键有机碳占有机碳总量比值的增加率始终比钙键有机碳占有机碳总量比值的增加率要高;覆膜比不覆膜时铁/铝键有机碳占有机碳总量比值的增加率比钙键有机碳占有机碳总量比值的增加率高得多。这表明,与全土有机碳相比,有机碳矿化稳定性由高到低依次是铁/铝键有机碳、钙键有机碳、全土有机碳。     

碳达峰与碳中和目标下水土保持碳汇的机理、途径及特征

[目的] 瞄准中国碳达峰、碳中和目标及其时间表,探索水土保持碳汇的主要途径与特征,为全面提升水土保持碳汇能力,科学推进水土流失综合治理高质量发展提供借鉴。[方法] 参考和借鉴国内外相关研究成果,系统性地分析了水土保持碳汇的学科应用基础及其协同作用机理,主要途径和物质表现,总结提出了水土保持碳汇的主要特征。[结果] 水土保持碳汇作用是在植物措施、工程措施和耕作措施3大类水土保持措施的共同参与下,通过植物、土壤和水体等多种途径协同发挥的,可消减大气中CO₂并将其转化为多种含碳化合物储存在植物及其产品、土壤和水体中。水土保持碳汇途径包括植物途径、土壤途径和水体途径。水土保持碳汇物质包括生物量、无生命有机质、土壤有机质和水体碳素。水土保持碳汇主要特征包括多种治理措施共同作用;多种碳汇途径相互交织;碳汇物质的现地性;碳汇特征短历时碳汇明显,全周期呈弱碳汇。[结论] 生态文明建设新阶段的水土保持工作,应全面推行碳汇水土保持,实施碳汇监测评价,扩大高碳汇水土保持措施,开展清洁生态小流域建设,避免水土流失与其治理措施损毁导致的碳排放,进一步提升碳汇增量,巩固碳汇能力。     

Positive and negative carbon mineralization priming effects among a variety of biochar-amended soils

Pyrogenic carbon (biochar) amendment is increasingly discussed as a method to increase soil fertility while sequestering atmospheric carbon (C). However, both increased and decreased C mineralization has been observed following biochar additions to soils. In an effort to better understand the interaction of pyrogenic C and soil organic matter (OM), a range of Florida soils were incubated with a range of laboratory-produced biochars and CO₂ evolution was measured over more than one year. More C was released from biochar-amended than from non-amended soils and cumulative mineralized C generally increased with decreasing biomass combustion temperature and from hardwood to grass biochars, similar to the pattern of biochar lability previously determined from separate incubations of biochar alone.The interactive effects of biochar addition to soil on CO₂ evolution (priming) were evaluated by comparing the additive CO₂ release expected from separate incubations of soil and biochar with that actually measured from corresponding biochar and soil mixtures. Priming direction (positive or negative for C mineralization stimulation or suppression, respectively) and magnitude varied with soil and biochar type, ranging from −52 to 89% at the end of 1 year. In general, C mineralization was greater than expected (positive priming) for soils combined with biochars produced at low temperatures (250 and 400 °C) and from grasses, particularly during the early incubation stage (first 90 d) and in soils of lower organic C content. It contrast, C mineralization was generally less than expected (negative priming) for soils combined with biochars produced at high temperatures (525 and 650 °C) and from hard woods, particularly during the later incubation stage (250-500 d). Measurements of the stable isotopic signature of respired CO₂ indicated that, for grass biochars at least, it was predominantly pyrogenic C mineralization that was stimulated during early incubation and soil C mineralization that was suppressed during later incubation stages. It is hypothesized that the presence of soil OM stimulated the co-mineralization of the more labile components of biochar over the short term. The data strongly suggests, however, that over the long term, biochar-soil interaction will enhance soil C storage via the processes of OM sorption to biochar and physical protection.     

Recovery of organic carbon by the walkley and black procedure in highly weathered soils

Abstract

The effect of soil series, cultivation, soil depth, and parent material on the correction factor which should be applied to organic carbon values determined by the method of Walkley and Black, has been examined using 450 low‐activity‐clay soil samples from high rainfall tropical Queensland. There were minimal effects due to soil depth, and differences between virgin and cultivated soils were greatest in soils formed on beach sands. However, soils formed on granitic or metamorphic rocks require a factor of 1.24, whereas the originally recommended factor of 1.32 (Walkley and Black) has been confirmed for soils formed on basalt, alluvium, and beach sands.     

Soil Carbon and Nitrogen Fractions of a Grassland in Central Missouri,USA

Quantification of soil carbon (C) and nitrogen (N) fractions in grasslands is vital for estimating C sequestration and climate change studies. We quantified background soil total carbon (TOC) status, recalcitrant carbon (RC), acid hydrolysable labile carbon (AHC), hot- and cold-water extractable carbon (HWC and CWC, respectively) fractions in the grassland in this study. Soil C fractions were as follows: TOC (11,633 to 15,525 mg C kg^?1); RC (11,500 to 15,357 mg C kg^?1); AHC (132 to 168 mg C kg^?1); HWC (57 to 70 mg C kg^?1); and CWC (27 to 33 mg C kg^?1). Labile C fractions contributed at most 1.2% to total C. Concentrations of total N ranged from 1072 to 1230 g N kg^?1. Recalcitrant C contributed higher amounts (>90%) to total C, indicating the incorporation of C into the stable C fraction. Carbon dioxide (CO₂) and nitrous oxide (N₂O) fluxes were not significantly correlated with total C.     

浙江省碳安全评价及其影响因素研究

[目的]研究浙江省碳足迹、碳承载力的测度及结构,分析其碳安全程度及影响因素,为发展低碳经济提供参考和依据。[方法]测度2000—2015年浙江省碳足迹和碳承载力,构建碳压力指数、碳足迹指数评价体系评价其碳安全程度;采用STIRPAT模型和岭回归方法对浙江省碳足迹的影响因素进行实证分析。[结果]浙江省碳足迹经历了先增加后稳定并略微下降的过程,碳承载力基本稳定;能源利用效率逐年提高,经济发展对能源的依赖程度降低;浙江省碳压力指数在1.35~4.19,碳足迹指数在0.21~0.59,碳足迹总体处中等以上水平;回归结果表明,人口、城镇化率、GDP、第二产业占比、原煤碳足迹占比是浙江省碳足迹的主要驱动因素。[结论]浙江省碳足迹较大,碳安全程度总体较低。为实现低碳经济目标,应通过控制人口数量,提高城镇化质量,发展低碳产业,促进高碳产业低碳化,推广使用清洁能源等措施减少碳足迹,同时增加城市绿化面积,保护森林以增加碳承载力。     

秸秆覆盖对冬小麦农田土壤有机碳及其组分的影响

通过对黄土高原旱塬区冬小麦地4种覆盖方式下(无覆盖对照处理(CK)、全生育期9 000kg/hm~2秸秆覆盖(M1)、全生育期4 500kg/hm~2秸秆覆盖(M2)和夏闲期9 000kg/hm~2秸秆覆盖(SM))土壤的田间定位试验和室内分析,探讨不同秸秆覆方式对冬小麦地土壤有机碳及其组分含量以及各组分之间相关性的影响。结果表明:(1)较CK(无覆盖对照)处理,M1(全生育期9 000kg/hm~2)、M2(全生育期4 500kg/hm~2)和SM(夏闲期9 000kg/hm~2)处理,均显著增加0—10cm和10—20cm土层的土壤有机碳、微生物量碳、潜在矿化碳和颗粒有机碳含量(p0.05),而20—40cm土层差异不明显,其中M1(全生育期9 000kg/hm~2)处理效果最佳,SM(夏闲期9 000kg/hm~2)处理作用相对较弱。(2)不同覆盖方式影响土壤微生物量碳、潜在矿化碳和颗粒有机碳在总有机碳中的分配比例,土壤微生物量碳、潜在矿化碳和颗粒有机碳的相对含量变化范围分别为1.96%~3.31%,2.83%~3.78%,18.13%~37.25%。(3)各覆盖方式下土壤有机碳及其组分含量都随着土层的逐渐深入而下降,且土层越深,变化越趋于缓慢。(4)不同覆盖方式下的土壤有机碳及其组分含量两两之间均达到了极显著正相关关系(p0.01),颗粒有机碳、微生物量碳和潜在矿化碳与土壤有机碳的相关系数依次为:0.847,0.700,0.614,可见微生物量碳、潜在矿化碳、颗粒有机碳含量在一定程度上决定于土壤有机碳的贮存量。综上所述,秸秆覆盖对土壤有机碳及其组分含量具有增加效应,全生育期9 000kg/hm~2秸秆覆盖方式实际运用价值较高。颗粒有机碳和微生物量碳的动态变化更能反映土壤有机碳的早期变化,是土壤肥力变化更加敏感的指标。     

区域农田生态系统碳足迹时空差异分析——以江苏省为案例

以江苏省为案例,应用江苏省1995—2009年化肥用量、农药消耗量、灌溉面积、农机燃料用量、农膜用量、耕地面积、农作物产量等数据,测算了区域农田生态系统碳吸收、碳排放及碳足迹的变化动态,以及在各地市的空间分布特征。结果表明：近15a来,江苏省农作物碳吸收总量和碳吸收强度呈＂V＂字形变化,变化范围分别为2933.6×104～3896.9×104t·a-1和6.04～7.71t·hm-2·a-1。农业投入碳排放呈逐渐上升趋势,由727.2×104t·a-1增长至882.7×104t·a-1,同时碳排放强度从1.43t·hm-2·a-1上升到1.88t·hm-2·a-1,增长了31.5%,化肥排放始终占据主导地位。农田生态系统碳足迹呈现波动增长,变化在13.68×105～17.56×105hm·2a-1之间,占同期耕地面积的比重达到27.0%～36.1%,碳生态盈余呈明显减少趋势,变化在36.99×105～32.22×105hm2·a-1之间。各地市之间碳足迹存在明显差异,空间分布格局为由北向南递减。