长期不同施肥处理对黑土不同组分有机碳的影响

以吉林省农业科学院土壤肥料研究所"国家黑土肥力与肥料效益长期定位监测基地"土样为材料,对长期施肥条件下不同施肥处理土壤有机碳、活性有机碳和颗粒有机碳进行了研究。结果表明:有机肥配施化肥有利于提高黑土有机碳含量,长期不同施肥处理对土壤水溶性有机碳和微生物量碳的影响差异显著,高量有机肥与化肥配施处理含量最高,长期施用化肥降低了土壤颗粒有机碳含量,有机肥的施用可以显著提高黑土有机碳含量。     

江西省不同农业土地利用方式对土壤有机碳的影响

研究目的:研究江西省不同农业土地利用方式下的土壤有机碳含量。研究方法:实地土壤样品采集分析与第二次土壤普查资料相结合、GIS空间插值与比较分析相结合的综合研究方法。研究结果:江西省农业土地利用方式和土壤类型不同,土壤有机碳含量存在较大差异;在农业土地利用方式下表层土壤有机碳含量一般为:菜地稻田有林地旱地土壤荒草地;从第一次土壤普查到2008年稻田土壤有机碳含量逐步提高,而且所有农业土地利用方式下土壤有机碳含量均随土壤深度增加而减少。研究结论:通过农业土地利用管理和土壤管理措施的调整,可以增加土壤有机碳的贮量,提高农田有机碳稳定性,减缓大气中CO2浓度增加。     

DEM分辨率对苏北地区耕地土壤有机碳制图精度的影响研究

[目的]数字高程模型（Digital Elevation Model, DEM）的分辨率大小决定区域地貌形态特征的表达程度,但目前DEM对于局部地形变异大的平原地区土壤有机碳制图精度的影响尚不明确。[方法]文章以江苏北部耕地区域为例,利用随机森林算法,建立不同分辨率DEM下的地形、气候、植被、土壤、成土母质与土壤有机碳之间的关系模型,分析DEM分辨率对局部地形变异大的平原区土壤有机碳制图精度的影响程度。[结果]（1）不同DEM分辨率下,地形、气候、植被、土壤与成土母质5类因子对土壤有机碳含量的影响程度依次降低;（2）当DEM分辨率在大于150 m的范围内变化时,环境特征因DEM的“概化”而逐步缺失细节信息,从而导致土壤有机碳含量预测精度随分辨率的增加而降低;（3）地形是苏北耕地区域土壤有机碳空间分布差异的最重要影响因子。[结论] DEM分辨率在60-90 m范围内时,整体平坦但局部地形变异程度较大的苏北地区土壤有机碳制图效果最佳。该研究为进一步提高我国相似地貌类型区土壤有机碳制图精度提供了理论依据。     

东北地区土壤活性有机碳对水热梯度变化的反映S152.4+2S153.6

基于样区20年气象资料统计结果和2006年土壤有机碳实测值,分析了东北样区内土壤活性有机碳各组分的空间分布格局及其与年均温(t)、降雨量(p)、有效积温和p/t(降雨量/年均温)之间的关系。结果表明:样区内土壤活性有机碳各组分沿纬度呈现出南低北高的分布趋势;活性有机碳各组分与土壤有机之间具有显著的正相关性;活性有机碳组分之间具有较强的相关性;活性有机碳各组分与气候因素之间存在良好的相关性。活性有机碳各组分与年均温之间的相关性大于活性有机碳各组分与降雨量之间的相关性。     

水产养殖与植被恢复对红树林湿地土壤的影响

通过对原生红树林、养殖虾塘和鸭塘、废弃虾塘表层土壤中全氮、全磷、全钾、土壤微生物总DNA以及土壤有机碳指标测定,得到养殖对红树林湿地土壤的影响以及红树林恢复对废弃虾塘土壤的修复作用。结果显示：原生红树林中的全氮和土壤有机碳含量较高;废弃虾塘A的全氮和废弃虾塘B的土壤有机碳最低;全磷含量在鸭塘最高,在废弃虾塘B最低;全钾在废弃虾塘A中的含量较其他4个样地高,最低值为鸭塘;土壤表层微生物总DNA浓度为鸭塘最高,废弃虾塘A最低;土壤C/N随着土壤微生物总DNA的升高而降低。植被恢复后,废弃虾塘土壤中土壤有机碳、全氮升高,全钾逐渐下降,而全磷变化较大,且这4个指标总体逐渐接近原生红树林中相应指标值。说明废弃虾塘植被恢复后,土壤性质逐步接近原生红树林土壤,红树林对废弃虾塘土壤有修复功能。     

近20年海南岛热带农田生态系统碳足迹时空格局演变

目的 厘清农田生态系统碳动态及其影响因素,为海南发展热带特色高效农业,推进国家生态文明试验区建设提供理论依据和数据支撑。方法 文章基于1999—2018年海南岛县域尺度的农田生产投入及作物产量等数据,构建农田生态系统碳足迹模型,利用ArcGIS 10.4、SPSS 21.0等平台,探讨海南岛农田生态系统碳足迹时空变化及其影响因素。结果 研究期间海南岛农田生态系统碳排放总量呈波动增长,年均增幅1.15%,其中,土壤呼吸占碳排放量比例最高,为52.52%;碳吸收总量呈现先上升后下降的趋势,拐点发生在2013年,作物结构调整是碳吸收总量下降主要原因;海南岛农田生态系统碳足迹总量呈波动增长趋势,年均增长率为2.94%,2016年农田系统碳平衡由生态盈余转为生态赤字。从空间上看,碳排放、碳吸收和碳足迹总量都呈四周沿海地区高,中部内陆地区低的分布格局;但单位面积碳足迹呈现东南高,西北低的空间分布规律。结论 研究期间海南岛各县市的农田系统碳足迹呈持续增长趋势,农田生态系统碳汇功能持续减弱,并在2016年由碳汇转变为碳源,调整优化农业产业结构和加强田间管理是增加农田生态系统碳汇功能的主要措施。     

黑土生态系统脆弱性成因与修复

黑土生态系统脆弱性成因自然因素和人为因素共同作用的结果;自然因素是水土流失发生发展的潜在条件,人为因素对水土流失的发生发展起了促进和加速作用;遵循生物种群与环境相适应原则,对不同地貌类型导致生物生态分异,生物种群必须与地貌格局相一致;将黑土脆弱区分为3个生态系统进行生态修复。     

农田生态系统碳足迹法:误区、改进与应用 ———兼析中国集约农作碳效率

近10多年来,国内外农田生态系统碳足迹研究蓬勃开展并取得了某些成果。同时也存在着问题与 误区,主要是碳流路径的短路和指标逻辑起点不一,导致研究结果的失真与扭曲。该文论述了全环式与半 环式碳流路径的利弊,提出了改进3原则,对当前世界流行的5种指标体系进行比较、综合、筛选、补充 与改进,初步形成了适合中国实际情况的包括碳流路径、指标体系及相应参数的碳足迹方法论,并通过 1950年以来的全国性农田系统碳流分析和现代高效农田的案例加以验证和剖析,与当前流行的一些主流观 点相悖,运用改进的碳足迹法进行的案例研究发现:（1）与多年生林木相似,农田上连年种植的一年生作 物同样具有净固碳作用;（2）1952～2012年期间,随着农业集约化程度的不断提高,全国农田生态系统碳 效率仍保持在正平衡状态;（3）尽管农田化合物大量投入,但在农田生态系统内增加的固碳量仍超过耗碳 量,化学合成物在农田生态系统的合理应用也有减少温室气体的可能性。     

滁州市陆地生态系统土壤碳储量对土地利用变化响应

从土地利用变化造成的非建设用地土壤有机碳储量变化,及土壤有机碳储量对土地利用变化脆弱性评估两个角度,研究2005-2013年滁州市陆地生态系统土壤碳储量对土地利用变化响应。研究发现:(1)土地利用强度逐年增加,土地利用变化主要表现为耕地、林地、水域、建设用地的增加和其他用地的大幅减少。建设占用导致大量农用地发生非农转用,耕地保护形势日趋严峻。(2)2005、2009、2013年,滁州市非建设用地的中层土壤有机碳储量为13090.11t、12538.86t和12500.05t,呈现先快后慢的减少态势,这主要受草地碳储量减少速率影响;耕地、林地和水域的储碳量最高。(3)2005-2013年,土地利用变化对非建设用地土壤有机碳储量的潜在影响指数为-2.05,前后4年潜在影响逐渐降低,脆弱程度有所改善,但仍不理想,土地利用有待向更加低碳的模式转变。     

寒温带落叶松林不同林型土壤有机碳含量及相关性分析

本文以大兴安岭呼中国家级自然保护区四种主要落叶松林型为研究对象,分析了四种不同落叶松林型土壤有机碳的分布特征及其影响因素。将样地土壤分为A层(腐殖质层)与B层(土壤层)。结果表明,影响该地区土壤有机碳含量的主要因素为低地植被的种类与密度。四种落叶松林土壤有机碳含量大小关系为:泥炭藓-落叶松林杜香-落叶松林杜鹃-落叶松林草类-落叶松林。A层各植被类型土壤有机碳含量为:杜香-落叶松林泥炭藓-落叶松林杜鹃-落叶松林草类-落叶松林。B层各植被类型土壤有机碳含量为:泥炭藓-落叶松林杜鹃-落叶松林草类-落叶松林杜香-落叶松林。四种林型中除杜鹃-落叶松林与草类-落叶松林在B层土壤有机碳含量上无显著差异,其余林型土壤有机碳含量差异均显著。土壤容重、土壤含水量与土壤有机碳之间有良好的相关性。结果表明土壤有机碳含量与土壤含水量表现为显著正相关(P0.05),与土壤容重变现为显著负相关(P0.05)。     

The Economic Value of Soil Quality under Alternative Management in the Canadian Prairies

This paper describes a dynamic simulation model that integrates environmental and economic components of agricultural crop production systems to predict changes in soil quality and the concomitant impact on economic returns. The model is used to simulate crop yield, soil quality and economic performance of a conventional crop rotation and several alternative crop rotations in two contrasting environments in western Canada over a 50-year period. This information is used to quantify the impact of the crop rotations on soil organic carbon (SOC) and the economic value of on-site SOC changes. The estimated value of these impacts range from $0.20/t to $2.10/t of SOC/ha/yr.     

Long-term effects of crop residues and fertility management on carbon sequestration and agronomic productivity of groundnut–finger millet rotation on an Alfisol in southern India

The data from long-term management and cropping systems experiments are needed to assess changes in soil quality, organic carbon pool, and agronomic sustainability. Thus, a 13-year-old soil fertility management experiment was used to assess the impact of crop residues carbon (C) inputs on SOC stock in a rainfed groundnut (Arachis hypogeae L.)–fingermillet (Eleusine coracana (L.) Gaertn) rotation in semiarid alfisol. The application of farmyard manure (FYM) alone or in a combination with chemical fertilizers contributed to higher amounts of C inputs and subsequently to build up a higher SOC pool. Application of 10?Mg?ha^?1 of FYM and a recommended dose of chemical fertilizer (25:21.8:20.7 and 50:21.8:20.7?kg?N, P, K ha^?1 for groundnut and fingermillet, respectively) increased soil SOC pool by 41.2% to 73.0?Mg?ha^?1 with an increase of 9.3?Mg?ha^?1 over 13 years. Both SOC pool and rates of its sequestration were positively correlated with cumulative C input and sustainable yield index. A minimal input of 1.62?Mg?C?ha^?1?yr^?1 is needed to maintain SOC pool at the antecedent level. Balanced application of NPK fertilizers is needed to reduce and reverse the depletion of SOC pool.     

Gliricidia sepium Carbon Inputs and Soil Carbon Pools in a Costa Rican Alley Cropping System

Alternative land management practices, including agroforestry, help to maintain levels of soil organic matter (SOM) and can facilitate soil carbon (C) sequestration for mitigating atmospheric CO₂ emissions. This study quantified C inputs and determined the changes of the soil C pool in a 19-year-old Gliricidia sepium alley cropping system, studied at two fertiliser levels (tree prunings only [? N], and tree prunings plus chicken manure [+ N]), and was compared to a sole crop system. Carbon input from tree prunings ranged from 455 to 457 g C m^{? 2} y^{? 1}, whereas C inputs from crop residues were similar between alley- and sole crops ranging from 121 to 159 g C m^{? 2}y^{? 1}. The soil organic C (SOC) pool in the alley crop was 16–23% higher than the sole crop. In the 19th year of alley farming, SOC was significantly higher (p < 0.05) in the alley crop (3.2%) compared to the sole crop (2.4%), and was also greater compared to that at the time of establishment of the agroforestry system (2.8%). Gross SOC turnover to a 20-cm depth ranged from 12 to 14 years in the + N and ?N alley crops compared to 49 and 50 years in the + N and ?N treatments for the sole crops. Residue stabilisation efficiency in the alley crops was 39% and 55% in + N and ?N treatments respectively.     

广东省惠来县土壤硒的分布特征及影响因素研究

[目的]开展对广东省惠来县土壤硒的调查研究,系统采集了表层土壤组合样321个,深层母质土壤组合样79个,测定土壤全硒含量,并据此研究土壤硒分布特征及主要影响因素。[方法]利用Pearson相关分析法与一元线性回归方法计算出土壤全硒含量与土壤理化性质和组分之间的相关性,GIS空间分析技术等方法对土壤硒的含量分布、富集特征及影响因素进行了系统的分析。[结果]惠来县土壤总体属于富硒水平。硒含量变化于0.02～1.41mg/kg,平均值为0.50mg/kg,明显高于全国土壤硒平均值0.29mg/kg。表层土壤富硒面积为60.75%,足硒面积为28.35%;深层土壤中,富硒和足硒面积分别达到了72.15%和20.25%。回归分析表明,土壤全硒含量与铁铝含量、有机碳含量具有极显著正相关,与pH呈极显著负相关。[结论]影响惠来县土壤硒含量的主要因素是成土母质,土壤pH、有机碳和铁铝含量及土地利用方式对土壤全硒含量分布与富集也有一定的影响。整体来看土壤硒含量水平较高,应针对富硒、足硒土地制定合理保护、开发和永续利用的方法与政策。     

Soil CO2 emission and carbon budget of a wheat/maize annual double-cropped system in response to tillage and residue management in the North China Plain

To investigate the impacts of tillage and crop residue managements on soil CO₂ emission and C budget in a wheat (Triticum aestivum L.)/maize (Zea mays L.) double-cropped system in the North China Plain (NCP), a field experiment was conducted consisting of four treatments: tillage with crop residues retention (CT+), tillage with crop residues removal (CT?), no-till with crop residues retention (NT+), and no-till with crop residues removal (NT?). Daily soil CO₂ fluxes changed with crop growing stage and peaked during the most vigorous growth of period, fluxes in maize season were higher than those in wheat season. Compared to the tilled soils, cumulative CO₂ emissions were significantly lower under no-till treatments. The largest cumulative CO₂ emission occurred under CT+ (65?g CO₂-C m^?2 y^?1) and the smallest was under NT+ (39?g CO₂-C m^?2 y^?1). After 5 years of the experiment, soil organic carbon (SOC) sequestration were greater with crop residues retention (CT+ and NT+) than with crop residues removal (CT? and NT?), the maximum SOC stock was in NT+ (5940?g C m^?2) while the minimum was in CT? (3635?g C m^?2). NT+ could help to mitigate CO₂ emission in the annual wheat/maize double-cropping system of the area.     

基于DNDC的茶园土壤碳素空间分异及其影响因素——以福建省安溪县为例

[目的]通过探究福建省安溪县茶园土壤碳素储量,揭示各碳素指标的空间分异特征及其关键影响因子,有助于为减少茶园温室气体排放和建设生态茶园提供决策支撑。[方法]文章运用反硝化分解（denitrification decomposition, DNDC）模型和空间统计分析方法对茶园土壤碳素进行模拟和研究。[结果]（1）经过参数率定的DNDC模型对茶园土壤碳素动态循环的模拟具有较好的适用性;（2）安溪茶园土壤有机碳含量丰富,土壤肥力较好。凋落物输入碳是茶园土壤碳素输入的主要来源,平均输入量为505.52 kg/hm2,而通过呼吸作用转化为CO2排放是茶园土壤碳素输出的重要途径,平均CO2排放量为883.78 kg/hm2;(3)茶园SOC10～20cm量、凋落物输入碳量、CH4排放量、CO2排放量均呈现空间聚集分布特征,主要分布在安溪县西部的低山与中低山地区;（4）初始土壤属性中黏粒含量和土壤有机碳含量是影响安溪县茶园土壤碳素空间分异的关键因子,其中土壤黏粒含量对茶园土壤CO2排放量和CH4排放量的影响最强且负向作用效果明显。[结论]安溪县西部等低山和中低山区域土壤肥力较好,但亦应谨慎对待该区...     

Managing tropical wetlands for advancing global rice production: Implications for land-use management

Being fertile lands, wetlands have been managed for traditional agriculture over millennia. However, the integrity and ecosystem services of wetlands are being jeopardized by intensive land-use comprising of drainage and excessive disturbance. An adhoc and intensive use of wetlands, without preserving ecological integrity is causing ecosystem disservices and threatening conversion of a large soil organic carbon (SOC) sink into a net source. Wetlands in the tropical parts of the world are distributed unevenly and represent ∼3% of the total world land area. Due to stagnancy and even reduction in rice (Oryza sativa) yield of many agricultural regions, there is a need for additional and alternative land-uses which can raise the global rice production to ∼1 billion Mg (megagram = 10⁶g = metric ton) by 2050 from ∼497 million Mg now. Wetlands can be a viable option to advance global food security because of high soil fertility and vast geographical distribution. A ‘3-tier rice production system’ is proposed herein based on specific hydrological niche to advance global food security without degrading the ecosystem services of wetlands. In addition to increasing agronomic yield, the proposed modus operandi can also improve the livelihood security of farmers through an additional income streams by: (i) trading of SOC credits generated through adoption of conservation agriculture in littoral zones, and (ii) promoting fish and duckery culture in conjunction with deepwater rice farming. Furthermore, the proposed strategies will also set in motion the process of restoration of wetlands while enhancing C sink capacity of the ecosystems.     

Improving China’s food and environmental security with conservation agriculture†

China has achieved impressive increases in agricultural output in recent decades. Yet, past approaches centred on a growing use of fertilizers, pesticides, fuel and water are not likely to achieve the required 30–50% additional increases in food production by mid-century. We show that efficiencies of production are falling and the costs of environmental harm are increasing. Agricultural innovations that improve natural capital are urgently needed. Conservation agriculture (CA) is now practised on >8?Mha in China and is offering promising prospects of both enhanced yields and environmental services. Our meta-analysis of 60 papers with 395 observations in China shows notable benefits from CA. Mean yield increase was 4.5% or 263?kg?ha^?1 for wheat, 8.3% or 424?kg?ha^?1 for maize, and 1.65% or 250?kg?ha^?1 for rice. In 34 datasets from 22 published papers (experimental duration: 2–17 years), 26 datasets (76.5%) show that CA increased yield and soil organic carbon (mean SOC increase of >3?g.kg^?1 in 0–10?cm soil depth) when compared with traditional tillage. Key priorities for the spread of more sustainable forms of agriculture in China are national policy and financial support, better coordination across agencies, and better extension for farmers.     

Forest fragmentation reduced carbon storage in a moist tropical forest in Bangladesh: Implications for policy development

Forest fragmentation is continued to be widespread in the tropics resulting in reduced ecosystem services including carbon storage. However, the effect of forest fragmentation is not considered in the current carbon policy. We investigated the effect of forest fragmentation on tree biomass carbon and soil organic carbon (SOC) storage in a moist tropical forest in Bangladesh. Above and below-ground tree biomass carbon were calculated by using widely accepted allometric equations and SOC was measured by sampling soils up to 10 cm depth and analyzing them in a soil laboratory. Results showed that carbon storage in tree biomass was significantly lower in fragmented forests (16.3 ± 1.37 t C ha⁻¹) than in contiguous forests (31.21 ± 2.75 t C ha⁻¹) (p < 0.001). Likewise, a significantly lower SOC was contained in the soils of fragmented forests (17.26 ± 0.83 t C ha⁻¹) than in contiguous forests (21.62 ± 0.78 t C ha⁻¹) (p < 0.001). Thus a total of 36% less carbon retained in tree biomass and soils in fragmented forests than in contiguous forests. Backward multiple linear regression analysis revealed tree density, tree height, tree DBH, height-diameter ratio (H/D) and tree species richness as influential factors of carbon variation in fragmented forests. All these structural parameters except tree species richness were significantly lower in fragmented forests, were positively associated with carbon storage and explained together 69% of the carbon storage variation. These findings suggest that the altered stand structure and tree allometry likely caused reduced carbon storage in fragmented forests and highlight the importance of landscape scale management intervention in the tropics. Here, we provided with the evidence of strong negative impact of forest fragmentation on carbon storage and argue that this effect should be in consideration which is currently overlooked in existing carbon accounting systems for tropical forests.