煤矿区复垦土壤压实时空变异特征

为了揭示煤矿区复垦土壤压实状况的时空变异规律,该文以未塌陷土地为对照,通过实地测定,分析5个复垦年限水平和垂直方面的土壤压实度变异特征。结果表明：复垦土壤表层压实度以复垦1 a（正在复垦）的最大,达到 2050 kPa,随着复垦年限增加逐渐减少,复垦5 a的最小（50 kPa）,基本达到未塌陷土地的压实度。表层土壤压实度空间变异最大的是复垦5 a的土地（变异系数为68.40%）,其次是未塌陷土地（52.58%）,最小的是正在复垦的土地 （22.01%）。从各层的变异情况看,正在复垦的土地各个层次土壤压实度都较大且变异系数较低,其他复垦年限土壤压实度上面3层较小但变异大,至第4层（22.86～30.48 cm）达到较高值,且变异较小,之下压实度基本稳定。     

马家塔露天矿区复垦土壤质量变化

以神东公司马家塔露天矿为例,选择土壤有机质、全N、有效P、速效K、pH值、含水率、紧实度、容重和EC9项指标对复垦土壤质量进行了综合评价。研究采用相关系数法确定指标权重,以隶属度函数对指标进行标准化处理,最后采用指数和法评定土壤质量。在研究区划分了5个复垦年限,并且在复垦5a的土地上采集了6种不同植被类型的土壤样品,分5个层次分别进行评价土壤质量。结果显示:随着复垦年限的增加表层土壤质量不断提高,并且表层高于下层;复垦后种植不同植被土壤质量差异较大,种植牧草、杨树较好,耕地和针叶树较差。     

Biochar application to soil for climate change mitigation by soil organic carbon sequestration

Pyrogenic carbon (C) is produced by incomplete combustion of fuels including organic matter (OM). Certain ranges in the combustion continuum are termed ‘black carbon' (BC). Because of its assumed persistence, surface soils in large parts of the world contain BC with up to 80% of surface soil organic C (SOC) stocks and up to 32% of subsoil SOC in agricultural soils consisting of BC. High SOC stocks and high levels of soil fertility in some ancient soils containing charcoal (e.g., terra preta de Índio) have recently been used as strategies for soil applications of biochar, an engineered BC material similar to charcoal but with the purposeful use as a soil conditioner (1) to mitigate increases in atmospheric carbon dioxide (CO₂) by SOC sequestration and (2) to enhance soil fertility. However, effects of biochar on soils and crop productivity cannot be generalized as they are biochar‐, plant‐ and site‐specific. For example, the largest potential increases in crop yields were reported in areas with highly weathered soils, such as those characterizing much of the humid tropics. Soils of high inherent fertility, characterizing much of the world's important agricultural areas, appear to be less likely to benefit from biochar. It has been hypothesized that both liming and aggregating/moistening effects of biochar improved crop productivity. Meta‐analyses of biochar effects on SOC sequestration have not yet been reported. To effectively mitigate climate change by SOC sequestration, a net removal of C and storage in soil relative to atmospheric CO₂ must occur and persist for several hundred years to a few millennia. At deeper soil depths, SOC is characterized by long turnover times, enhanced stabilization, and less vulnerability to loss by decomposition and erosion. In fact, some studies have reported preferential long‐term accumulation of BC at deeper depths. Thus, it is hypothesized that surface applied biochar‐C (1) must be translocated to subsoil layers and (2) result in deepening of SOC distribution for a notable contribution to climate change mitigation. Detailed studies are needed to understand how surface‐applied biochar can move to deeper soil depths, and how its application affects organic C input to deeper soil depths. Based on this knowledge, biochar systems for climate change mitigation through SOC sequestration can be designed. It is critically important to identify mechanisms underlying the sometimes observed negative effects of biochar application on biomass, yield and SOC as biochar may persist in soils for long periods of time as well as the impacts on downstream environments and the net climate impact when biochar particles become airborne.     

Soil organic carbon stock for reclaimed minesoils in northeastern Ohio

Reclamation of disturbed soils is done with the primary objective of restoring the land for agronomic or forestry land use. Reclamation followed by sustainable management can restore the depleted soil organic carbon (SOC) stock over time. This study was designed to assess SOC stocks of reclaimed and undisturbed minesoils under different cropping systems in Dover Township, Tuscarawas County, Ohio (40°32·33′ N and 81°33·86′ W). Prior to reclamation, the soil was classified as Bethesda Soil Series (loamy‐skeletal, mixed, acid, mesic Typic Udorthent). The reclaimed and unmined sites were located side by side and were under forage (fescue—Festuca arundinacea Schreb. and alfa grass—Stipa tenacissima L.), and corn (Zea mays L.)—soybean (Glycine max (L.) Merr.) rotation. All fields were chisel plowed annually except unmined forage, and fertilized only when planted to corn. The manure was mostly applied on unmined fields planted to corn, and reclaimed fields planted to forage and corn. The variability in soil properties (i.e., soil bulk density, pH and soil organic carbon stock) ranged from moderate to low across all land uses in both reclaimed and unmined fields for 0–10 and 10–20 cm depths. The soil nitrogen stock ranged from low to moderate for unmined fields and moderate to high in some reclaimed fields. Soil pH was always less than 6·7 in both reclaimed and unmined fields. The mean soil bulk density was consistently lower in unmined (1·27 mg m⁻³ and 1·22 mg m⁻³) than reclaimed fields (1·39 mg m⁻³ and 1·34 mg m⁻³) planted to forage and corn, respectively. The SOC and total nitrogen (TN) concentrations were higher for reclaimed forage (33·30 g kg⁻¹; 3·23 g kg⁻¹) and cornfields (21·22 g kg⁻¹; 3·66 g kg⁻¹) than unmined forage (17·47 g kg⁻¹; 1·98 g kg⁻¹) and cornfield (17·70 g kg⁻¹; 2·76 g kg⁻¹). The SOC stocks in unmined soils did not differ among forage, corn or soybean fields but did so in reclaimed soils for 0–10 cm depth. The SOC stock for reclaimed forage (39·6 mg ha⁻¹ for 0–10 cm and 28·6 mg ha⁻¹ for 10–20 cm depths) and cornfields (28·3 mg ha⁻¹; 32·2 mg ha⁻¹) were higher than that for the unmined forage (22·7 mg ha⁻¹; 17·6 mg ha⁻¹) and corn (21·5 mg ha⁻¹; 26·8 mg ha⁻¹) fields for both depths. These results showed that the manure application increased SOC stocks in soil. Overall this study showed that if the reclamation is done properly, there is a large potential for SOC sequestration in reclaimed soils. Copyright © 2005 John Wiley & Sons, Ltd.     

土地整理对农田土壤碳含量的影响

土地整理对土壤的强扰动会影响土壤的碳循环平衡,为了研究土地整理对农田土壤碳含量的影响,通过间接采样和随机采样方法,采集了江苏3个土地整理区土地整理前后土样进行有机质测定,初步分析了不同土地整理区土地整理后的土壤碳含量变化及其变化差异原因。主要结论有：1）通过土地整理,3个土地整理区土壤碳含量都有得到提高。其中,苏南丹阳土地整理区碳质量分数提高了26.05%,碳密度提高23.87%,提高幅度最大,碳密度变化方向与碳含量变化具有一致性,但提高幅度低于碳含量。这与各整理区原有土质、土地整理工程施工方式、施工时间等因素密切相关。2）水田碳质量分数显著高于旱地碳质量分数,但是经过土地整理旱地碳含量提高幅度大于水田,水田在整理前后碳含量变化幅度不大。3）在土地整理项目实施前应制定适宜的土地整理规划,实施有利于土壤固碳的土地整理工程。     

基于Web的煤矿废弃地土地复垦决策支持系统设计与实现

为了克服现有煤矿废弃地土地复垦与植被恢复试验法费时费力的缺陷,根据土壤基质和气候相似性原理,采用模糊综合评价一灰色关联优势分析、基于距离的相似算法、基于规则的推理等多种数学方法,分别从植被恢复潜力评价、适生植物品种选择、土地复垦方案选择3个方面建立了相关数学模型,解决了煤矿废弃地恢复潜力的分级、先锋植物选种和土地复垦方案的确定等问题,从而为煤矿废弃地的植被恢复提供了一系列的决策支持.并使用ASENET 等编程语言结合MS Access数据库设计并开发了基于web的煤矿废弃地植被恢复的决策支持系统,该系统能为煤矿废弃地植被恢复工作提供新的研究模式和手段,并已经在辽宁省阜新矿区得到应用,结果表明系统所采用的方法科学、合理、可行.     

闭矿后矿区土地复垦生态安全评价研究

该文运用模糊数学与层次分析法相结合对闭矿后的矿区土地复垦生态安全进行评价。将影响矿区土地复垦生态安全的土壤因素、水文因素、地质因素、风因素、矸石山因素、采空区因素以及其他因素作为影响因素的第一层加以考虑,建立数学模型。根据权重及安全性等级的隶属度得到模糊矩阵,进一步求得矿区土地复垦的生态安全度。作者以某关闭矿区为例,进行了复垦土地安全性评价,结果表明该矿区复垦土地的生态安全性较高。该方法对闭矿后矿区土地复垦生态安全评价具有一定的指导意义。     

Soil restorative effects of mulching on aggregation and carbon sequestration in a Miamian soil in central Ohio

Soils play a key role in the global carbon cycle, and can be a source or a sink of atmospheric carbon (C). Thus, the effect of land use and management on soil C dynamics needs to be quantified. This study was conducted to assess: (1) the role of aggregation in enhancing soil organic carbon (SOC) and total soil nitrogen (TSN) concentrations for different mulch rates, (2) the association of SOC and TSN with different particle size fractions, and (3) the temporal changes in the SOC concentration within aggregate and particle size fractions with duration of mulching. Two experiments were initiated, one each in 1989 and 1996, on a Crosby silt loam (Aeric Ochraqualf or Stagnic Luvisol) in central Ohio. Mulch treatments were 0, 8, and 16 Mg ha⁻¹ yr⁻¹ without crop cultivation. Soil samples from 0–5 cm and 5–10 cm depths were obtained in November 2000; 4 and 11 years after initiating the experiments. Mulch rate significantly increased SOC and TSN concentrations in the 0–5 cm soil layer only. The variation in the SOC concentration attributed to the mulch rate was 41 per cent after 4 years of mulching and 52 per cent after 11 years of mulching. There were also differences in SOC and TSN concentrations among large aggregate size fractions, up to 2 mm size after 4 years and up to 0ċ5 mm after 11 years of mulching. There were also differences in SOC and TSN concentrations among particle size fractions. Variation in the SOC concentration in relation to particle size was attributed to clay by 45–51 per cent, silt by 34–36 per cent, and to sand fraction by 15–19 per cent. Bulk of the TSN (62–67 per cent) was associated with clay fraction and the rest was equally distributed between silt and sand fractions. The enrichment of SOC and TSN concentrations in the clay fraction increased with depth. The C:N ratio was not affected by the mulch rate, but differed significantly among particle size fractions; being in the order of sand >silt >clay. Copyright © 2003 John Wiley & Sons, Ltd.     

Effect of different fertilization modes on soil organic carbon sequestration in acid soils

ABSTRACT

A meta-analysis of 297 treatment data from the Vezaiciai Branch of the Lithuanian Research Centre for Agriculture and Forestry long-term field experiment published from 2006 to 2015 was used to characterize the changes in SOC under different fertilization treatments and residue management practices in Lithuania’s acid soil. A meta-analysis was performed to quantify the relative annual change (RAC) of SOC content and the average RAC rate of SOC under four fertilization modes (farmyard manure (FYM) (40?t?ha^?1)); alternative organic fertilizers (in the manure background (40?t?ha^?1)); FYM (60?t?ha^?1); alternative organic fertilizers (in the manure background (60?t?ha^?1)) in two soil backgrounds (naturally acid and limed soil). The average RAC under four fertilization modes was 1.46 g?kg^?1?yr^?1, indicating that long-term fertilization had considerable SOC sequestration potential. Incorporation of alternative organic fertilizers in unlimed soil showed negative effects (?0.39 and ?0.66 g?kg^?1?yr^?1) in the observed long-term experiment. The RAC in the limed soil with incorporated organic fertilizers (FYM and alternative organic fertilizers), compared to the control, and varied from 0.25 g?kg^?1?yr^?1 in the treatment with incorporated alternative organic fertilizers (in the manure background (40?t?ha^?1)) to 0.71 g?kg^?1?yr^?1 in the soil with FYM (60?t?ha^?1). In this study, the average RAC rate of SOC under organic fertilization treatments in limed soil (5.07–6.54%) was longer than organic fertilization in unlimed soil (2.11–3.49%), which might be attributed to the application of organic manure that would result in a slow release of fertilizer efficiency. Our results indicate that the application of manure (40 or 60?t?ha^?1) showed the greatest potential for C sequestration in agricultural soil and produced the longest SOC sequestration duration.     

施肥对喀斯特地区植草土壤活性有机碳组分和牧草固碳的影响

通过盆栽试验,研究施肥对喀斯特地区植草土壤不同活性有机碳组分和牧草固碳的影响。试验处理包括CK（不施肥）、 N1 （N 150 mg/kg）、 N2 （N 250 mg/kg）、 N1P1 （P2O5100 mg/kg）、 N2P2 （P2O5150 mg/kg）、 N1P1K1 （K2O 70 mg/kg）、 N1P1K2 （K2O 105 mg/kg）和N2P2K1和N2P2K2。结果表明,与对照（不施肥）相比,施肥处理增加植草土壤有机碳、 微生物量碳和易氧化碳,有机碳日矿化量和累积矿化量以及牧草固碳量。其中N1P1K1处理土壤有机碳和易氧化碳最高,N1P1处理土壤微生物量碳最高,N2P2K1处理土壤可溶性碳最高,N2P2K2处理牧草地上部及根系固碳量、 有机碳日矿化量和累积矿化量均最高。综上,低量氮磷钾肥配施有利于土壤活性有机碳的积累,高量氮磷钾平衡配施牧草固碳效果最佳。     

矿区复垦土壤碳组分对外源碳输入的响应特征

研究外源碳输入对复垦土壤有机碳及组分的影响,对于深入探究矿区复垦土壤有机碳提升及培肥管理具有重要意义。本文依托山西省襄垣县采煤沉陷复垦区的长期定位试验,研究了矿区复垦土壤碳组分对不同外源碳(生物炭、堆肥、沼渣、牛粪与秸秆)输入的响应特征。分别在2011年与2016年对矿区复垦土壤样品进行采集,测定0～20 cm土层土壤有机碳、易氧化有机碳、活性碳库Ⅰ、Ⅱ的含量。结果表明,生物炭处理的土壤有机碳增长率和年变化量较对照(CK,无外源碳添加)分别增加101.80%和0.56g·kg–1·a–1,且均显著高于其他有机物料处理;生物炭、牛粪处理土壤0～20 cm土层固碳量较CK分别提高100.52%和91.52%,二者间差异不显著,均显著高于其他有机物料处理,堆肥、沼渣和秸秆处理间对土壤固碳量的提升作用不显著。添加有机物料均能显著增加复垦土壤易氧化有机碳的增长率和年变化量,均表现为堆肥处理最高,较CK分别增加12.37%和0.16 g·kg–1·a–1。复垦土壤活性碳库Ⅰ、Ⅱ的增长率和年变化量均为牛粪处理显著高于其他有机物料处理。有机物料添加均能提高土壤稳定性有机碳含量,与CK相比,生物炭和牛粪处理的提高幅度最大,显著高于其他有机物料,而牛粪与生物碳之间差异不显著。生物炭处理碳库管理指数最高,分别较堆肥、沼渣、牛粪、秸秆处理提高36.30%、52.23%、41.50%、52.02%。施用生物炭、堆肥、沼渣、牛粪与秸秆都能显著提升复垦土壤各碳组分含量和碳库管理指数,施用生物炭的效果最优,因此施用生物炭可作为矿区复垦土壤有机碳提升的有效管理措施。     

秸秆还田模式对小麦-玉米轮作体系土壤有机碳固存的影响

为解决麦玉轮作体系小麦秸秆直接粉碎还田存在的弊端,基于多年麦玉秸秆还田定位试验,筛选高产-节本-地力提升为一体的还田模式。选择4种还田模式,即小麦玉米秸秆均不还田(WN-MN,CK1)、小麦玉米秸秆均粉碎还田(WC-MC,CK2)、小麦高留茬还田(WH-MN)和小麦高留茬-玉米粉碎还田(WH-MC)为研究对象,比较其产量表现、土壤有机碳贮量盈亏、碳库管理指数等指标,评价将小麦秸秆粉碎还田改成高留茬还田后形成的还田模式与两季秸秆均粉碎还田的优劣。结果表明,与WN-MN相比,WC-MC和WH-MC的土壤碳储量分别增加24.23%和16.05%;与试验开始前土壤有机碳储量相比,4种还田模式的土壤碳固持为–0.83~6.14 Mg·hm^–2;维持土壤初始碳储量水平的最小碳投入量为4.06 Mg·hm^–2·a^–1。各处理不稳定有机碳组分的含量随着土层加深呈下降趋势。与WN-MN相比,WC-MC、WH-MC和WH-MN显著增加了0~20 cm表层不稳定碳组分的含量;WC-MC和WH-MC也显著增加了各土层的碳库管理指数。2015—2016周年产量,WC-MC、WH-MC平均较其他两个处理分别增加了34.5%、20.1%;2016—2017周年产量,以WH-MC最高,较其他处理平均高出11.1%。小麦高留茬-玉米粉碎还田模式下土壤有机碳储量、不稳定有机碳组分、碳库管理指数和作物产量均较高,且节本增效,表明该模式有利于关中平原麦玉轮作体系粮食生产可持续发展。     

The soil organic carbon: Clay ratio in North Devon,UK: Implications for marketing soil carbon as an asset class

Building up stocks of agricultural soil organic carbon (SOC) can improve soil conditions as well as contribute to climate change mitigation. As a metric, the ratio of SOC to clay offers a better predictor of soil condition than SOC alone, potentially providing a benchmark for ecosystem service payments. We determined SOC:clay ratios for 50 fields in the North Devon UNESCO World Biosphere Reserve using 30 cm soil cores (divided into 0–10 cm and 10–30 cm depth samples), with soil bulk density, soil moisture and land-use history recorded for each field. All the arable soils exceeded the minimum desirable SOC:clay ratio threshold, and the ley grassland soils generally exceeded it but were inconsistent at 10–30 cm. Land use was the primary factor driving SOC:clay ratios at 0–10 cm, with permanent pasture fields having the highest ratios followed by ley grass and then arable fields. Approximately half of the fields sampled had potential for building up SOC stock at 10–30 cm. However, at this depth, the effect of land use is significantly reduced. Within-field variability in SOC and clay was low (coefficient of variation was ~10%) at both 0–10 cm and 10–30 cm, suggesting that SOC:clay ratios precisely characterized the fields. Due to the high SOC:clay ratios found, we conclude that there is limited opportunity to market additional carbon sequestration as an asset class in the North Devon Biosphere or similar areas. Instead, preserving existing SOC stocks would be a more suitable ecosystem service payment basis.     

黄土区大型露天煤矿复垦24a土壤碳氮组分特征

研究大型露天煤矿典型植被恢复模式下土壤碳、氮组分特征,为深入理解露天煤矿高压实复垦土壤碳、氮固持过程及复垦土壤成土过程提供依据。以黄土区典型露天煤矿-平朔露天煤矿的复垦24a的刺槐-油松混交林（RP）、刺槐纯林（RM）、白杆-青杆-沙棘混交林（PPH）、沙棘纯林（HM）4种典型植被恢复模式样地及未复垦样地（UR）、原地貌样地（UD）为研究对象,采集0～20 cm表层土壤样品,分析土壤碳、氮组分特征。结果表明：1）经过24a演替,复垦土壤理化性质得到明显提高,但各样地间土壤理化性质明显显著。2）同UR样地相比,RP、RM和PPH样地的土壤有机碳含量分别提高594.03%、158.66%、99.25%;RP和PPH样地的微生物生物量碳则分别提高174.68%、209.34%;RP和HM样地的水溶性碳分别提高110.13%、82.99%;RP、RM样地的易氧化碳含量则分别为UR样地的35.55倍和7倍。3) 与UR样地相比,RP、RM、PPH、HM样地的土壤全氮含量分别提高413.24%、250.00%、100%和82.35%;RP、PPH、HM样地的水溶性氮含量分别提高206.33%、153.02%、99.95%;PPH样地的微生物生物量氮含量提高368.07%。4）复垦土壤碳、氮组分之间呈现正相关关系,但与全钾呈现显著负相关（P<0.05）。上述结果表明,土地复垦显著提高了土壤碳、氮组分含量,尤以刺槐-油松混交林效果较好,但复垦24a后,矿区土壤可能存在钾限制的现象。     

Current trends of soil organic carbon in English arable soils

Abstract. A model of the impact of land management changes upon soil organic carbon (SOC) was constructed, and the total amount of topsoil organic carbon was estimated for the arable area of England from 1940 to 2000. The largest influence on the overall mean SOC in arable topsoils proved to be a decline in the area of both permanent and temporary grassland. SOC declined over a prolonged period (60 years), but has now reached a plateau. Modelling changes in mean values enabled a statistical evaluation to be made between a measured decline in the number of sites with 'high' SOC levels between 1980 and 1995, and the decline predicted by the model. The SOC content of arable soils in England was measured at National Soil Inventory sites twice in recent decades: in 1980 and 1995. The proportion of fine textured soils in the lowest SOC class (<2.3%) rose from just over 40% to about 50% over the same period. There was a significant difference between the observed values of 1995 and those expected from modelling the decline from 1980 values, in the category of 'low SOC' fine textured soils. The variation in the fine textured soils represents a significant and widespread decline in topsoil organic carbon concentrations, which was greater than the underlying long-term trend.     

Soil particulate organic carbon under different land use and management

Abstract. Changes in particulate organic carbon (POC) relative to total organic carbon (TOC) were measured in soils from five agronomic trial sites in New South Wales, Australia. These sites covered a wide range of different land use and management practices. POC made up 42–74% of TOC and tended to be greater under pasture and more conservative management than traditional cropping regimes. It was the form of organic carbon preferentially lost when soils under long-term pasture were brought under cultivation. It was also the dominant form of organic carbon accumulating under more conservative management practices (direct drilling, stubble retained and organic farming). Across all sites, changes in POC accounted for 81.2% (range 69–94%) of the changes in total organic carbon caused by differences in land use and management. Significant differences were found between pasture and cropped soils in the carbon content in the <53 μm fraction, particularly for hardsetting soils. However, even with these, POC was a more sensitive indicator of change caused by land use and management practices than TOC. The current method for measuring POC involves dispersion using sodium hexametaphosphate. The dispersing agent was found to extract 4–19 % of the TOC, leading to a significant under-estimation of POC.     

矿区土地复垦工程可垦性分析

该文论述了土地复垦规划中可垦性分析的重要性,阐述了可垦性分析的含义和内容,提出可垦性分析的一般程序和多因素综合评价法,即在选定评价单元的基础上,选择可垦性分析的主导因素,采用层次分析法给主导因素打分,采用乘法模型计算评价单元的可垦性综合分值,从而得到待复垦区域的可垦性分析值,通过量化的综合分值可以确定待复垦区域的可垦性。并以山东某矿采煤塌陷地为例进行分析,经验证该方法得出的评价结果能够反应待复垦区的实际情况,为土地复垦规划设计提供参考。     

Evaluation of the land reclamation project at the As Pontes Mine (NW Spain) in relation to the suitability of the soil for plant growth

The reclamation and monitoring methodologies implemented at the mining waste dump at the As Pontes Lignite Mine in Galicia (NW Spain) are briefly described. In addition the factors affecting achievement of reclamation objectives and an evaluation of the factors limiting plant growth on the constructed soils are outlined. The most serious limitations were found in the oldest mine soils constructed from sulphide-bearing spoils; high acidity, toxicity, nutrient deficiency, seasonal waterlogging due to their impermeability, and compaction. The youngest soils were constructed using sulphide-free spoils as topsoil substitutes and had fewer limitations for plant development. The results show that proper handling of spoils, and paying special attention to selective placement of sulphide bearing materials, are the most important factors in providing a suitable medium for plant growth. © 1998 John Wiley & Sons, Ltd.     

Land Use and Soil Organic Carbon in China’s Village Landscapes

Village landscapes, which integrate small-scale agriculture with housing, forestry, and a host of other land use practices, cover more than 2 million square kilometers across China. Village lands tend to be managed at very fine spatial scales (≤ 30 m), with managers both adapting their practices to existing variation in soils and terrain (e.g., fertile plains vs. infertile slopes) and also altering soil fertility and even terrain by terracing, irrigation, fertilizing, and other land use practices. Relationships between fine-scale land management patterns and soil organic carbon (SOC) in the top 30 cm of village soils were studied by sampling soils within fine-scale landscape features using a regionally weighted landscape sampling design across five environmentally distinct sites in China. SOC stocks across China’s village regions (5 Pg C in the top 30 cm of 2 × 10 6 km 2 ) represent roughly 4% of the total SOC stocks in global croplands. Although macroclimate varied from temperate to tropical in this study, SOC density did not vary significantly with climate, though it was negatively correlated with regional mean elevation. The highest SOC densities within landscapes were found in agricultural lands, especially paddy, the lowest SOC densities were found in nonproductive lands, and forest lands tended toward moderate SOC densities. Due to the high SOC densities of agricultural lands and their predominance in village landscapes, most village SOC was found in agricultural land, except in the tropical hilly region, where forestry accounted for about 45% of the SOC stocks. A surprisingly large portion of village SOC was associated with built structures and with the disturbed lands surrounding these structures, ranging from 18% in the North China Plain to about 9% in the tropical hilly region. These results confirmed that local land use practices, combined with local and regional variation in terrain, were associated with most of the SOC variation within and across China’s village landscapes and may be an important cause of regional variation in SOC.