皖北平原蒙城县农田土壤有机碳空间变异及影响因素

以皖北平原典型农业生产大县亳州市蒙城县为代表,运用统计学、地统计学方法和GIS技术研究了其农田耕作层(0～20 cm)土壤有机碳(SOC)含量的空间分布及其影响因子。结果表明:研究区SOC含量为10.41±2.52 g kg-1,近30年来提高了55.61%,SOC变异系数为24%,属于中等变异程度。SOC含量在空间分布上表现为东北部、中部和西南部含量高,由西北向东南先逐渐增加后逐渐降低,变异程度较高。整个县域范围内SOC空间变异的主要影响因素为土壤机械组成(粉粒和砂粒含量),其次为秸秆还田。     

大别山区江子河流域土壤有机质的空间变异

土壤有机质(Soil organic matter,SOM)是土壤的重要组成部分,是反映土壤肥力的重要指标,是全球碳循环的重要源和汇,目前已成为土壤学和环境学的研究热点之一[1]。土壤空间异质性是系统的某种属性在空间上的复杂性和变异性,是土壤重     

青藏高原生态系统土壤有机碳研究进展

作为"世界第三极"的青藏高原,高寒生态系统是青藏高原主要的生态系统之一.它本身是一个复杂而又特殊的系统,因其独特的自然地理环境而形成的高寒土壤更有其独特的性质.本文首先综述了青藏高原高寒生态系统的土壤有机碳储量、估算方法的研究进展及造成估算结果差异的原因,随后对高寒土壤有机碳排放的观测试验进行了综述,探讨了气候变化对高寒生态系统土壤有机碳源汇效应的影响.目前,全球变暖的趋势正在加剧,40 年来,青藏高原气温平均上升了约 0.3 ～ 0.4℃,冻土面积正广泛退缩,这直接导致青藏高原高寒生态系统发生了以植被覆盖度减少、高寒草原草甸面积萎缩等为主要形式的显著退化,植被生产力和土壤有机碳输入量都减少,而温度升高加快了土壤有机碳分解速率,从而影响到高寒生态系统的碳循环和碳储量.青藏高原土壤有机碳的源汇效应问题已成为研究的热点,但是到目前为止,温度升高到底如何影响土壤有机碳的动态变化没有明确的定论,为此,我们必须从长期的观测试验来说明气候变化对土壤碳库的源汇效应.     

四川省仁寿县土壤有机碳空间分布特征及其主控因素

准确地获取区域尺度内土壤有机碳含量信息对土壤碳调控及全球环境变化具有重要意义。本研究基于野外实地采集的555个表层(0~20 cm)土样,探讨四川省仁寿县土壤有机碳空间分布特征及其主控因素。运用方差分析和回归分析对比了成土母质、土壤类型和土地利用方式对仁寿县土壤有机碳空间分布的影响。结果表明:研究区表层土壤有机碳含量为3.36~37.10 g·kg-1,平均13.46 g·kg-1,变异系数为48.87%,属中等强度的空间变异性。块金效应C0/(C0+C)为66.7%,空间分布受结构性因素和随机性因素的共同影响,总体呈现北高南低的趋势。土地利用方式和土壤类型对土壤有机碳的影响极显著(P0.01),而成土母质的影响不明显(P=0.256)。土类能够独立解释23.7%的土壤有机碳空间变异;亚类和土类的解释能力接近,分别为27.0%和27.1%,土壤亚类可作为探讨该区域土壤有机碳空间变化的最小土壤分级单元。土地利用方式能独立解释53.0%的土壤有机碳空间变异,远大于土壤类型,是研究区土壤有机碳空间分布的主控因素。     

土食性大型土壤动物转化土壤有机碳的14C示踪法应用研究进展

土壤有机C是维持全球C平衡过程中的重要C库,其降解和转化在地球化学循环中占有重要地位。大型土壤动物对土壤有机C的稳定性起着重要的调控作用。14C示踪技术由于在测定目标化合物的转化速率和定位代谢产物和残留物分布上的优势,近年来在土壤有机C稳定性研究中得到了广泛应用。本文综述了3种典型土食性大型土壤动物,白蚁(Isoptera:Termitidae)、甲虫幼虫(Coleoptera:Scarabaeidae)和蚯蚓(Oligochaeta:Lumbricidae),对土壤稳态有机C降解转化的14C示踪研究结果及相关的微生物作用。食土白蚁和甲虫幼虫的极端碱性(pH10～12.5)肠道段和肠道内的特殊蛋白酶的共同作用促使这两种动物可以选择性地降解和矿化腐殖酸中的稳态多肽等组分,进一步提高腐殖酸的腐殖化程度。食土蚯蚓体内含有高活性的纤维素酶,能促进纤维素的降解。虽然木质素在蚓粪中能发生降解,蚯蚓也能降解植物树叶,但是食土蚯蚓能否降解或选择性降解稳态土壤有机C的研究还极少。大型土壤动物肠道内含有大量微生物及酶,这些微生物在土壤动物降解和腐殖化有机C的过程中所起的具体作用如何以及这些酶的来源还不是很清楚。文中总结了目前对大型土壤动物转化土壤有机C认识上的不足,并对一些优先研究方向提出了建议。     

Effects of organic wastes on labile organic carbon in semiarid soil under plastic mulched drip irrigation

ABSTRACT

The objective of this work was to evaluate the variation in labile organic carbon fractions after the application of organic wastes (OWs) in semiarid soil under plastic mulched drip irrigation. The two-year experiment involved six treatments: chicken manure (CM), sheep manure (SM), mushroom residue (MR), maize straw (MS), fodder grass (FG), and tree leaves (TL), with an unamended soil (no OWs) as control. In 2015 and 2016, treatment with OWs led to increased levels of soil organic carbon (SOC), dissolved organic carbon, microbial biomass carbon, easily oxidized organic carbon, as well as higher carbon management indexes and yields and lower oxidation stability coefficients. Higher SOC contents (p <0.01) were achieved in both years for TL and MS compared to the other OWs. In particular, the SOC content in 2016 was higher (p <0.05) for TL than MS. Compared to the other OWs, the easily oxidized organic carbon levels and carbon management indexes in both years were higher (p <0.01) for CM, SM, and MS, whereas the oxidation stability coefficients were lower (p <0.01). In conclusion, among the studied treatments, the application of MS was the most effective for improving soil fertility and enhancing soil carbon sequestration.     

长期施肥下石灰性潮土有机碳变化的DNDC模型预测

为探讨长期不同施肥条件下土壤有机碳的变化规律及DNDC模型的应用,利用封丘石灰性潮土不同施肥措施下的长期定位试验数据,选取CK、NPK、1/2NPK+1/2OM、OM4个处理,分析了15年来作物产量及土壤有机碳(SOC)的变化特征,并用DNDC模型预测了试验地近100年(2000~2099)的SOC变化趋势。结果表明,各施肥处理的多年产量平均值和对照处理差异显著;施用化肥(NPK和1/2NPK+1/2OM)处理和有机肥(OM)处理间也有显著差异;产量最高为NPK处理,达10811 kg/ha,CK处理最低,但1/2NPK+1/2OM处理产量与NPK处理无显著性差异。15年来土壤耕层(0—20cm)有机碳平均值,以OM处理最高,达到7.90 g/kg,显著高于1/2NPK+1/2OM、NPK处理;而CK处理仅为4.15 g/kg。从15年来有机碳的变化看出,CK处理略有下降,NPK处理较为平稳,而1/2NPK+1/2OM和OM处理呈现不断上升趋势,OM处理上升幅度较1/2NPK+1/2OM处理大。对试验地SOC变化趋势长期(100a)的模拟结果显示,与初始土壤SOC含量相比,100a后不施肥处理(CK)土壤有机碳含量下降了52%,化肥(NPK)处理土壤SOC含量较为稳定,而1/2NPK+1/2OM处理和OM处理土壤有机碳增加明显,大约25a后基本上稳定,100a后分别较2000年增加了24%和25%。从实测数据的分析和DNDC模型模拟分析可以看出,有机肥和化肥配施能获得较高作物产量,并能有效地增加土壤SOC含量,从而提高土壤的可持续利用能力。     

Soil organic carbon distribution in relation to land use and its storage in a small watershed of the Loess Plateau, China

Soil organic carbon (SOC) is an important component in agricultural soil, and its stock is a major part of global carbon stocks. Estimating the SOC distribution and storage is important for improving soil quality and SOC sequestration. This study evaluated the SOC distribution different land uses and estimated the SOC storage by classifying the study area by land use in a small watershed on the Loess Plateau. The results showed that the SOC content and density were affected by land use. The SOC content for shrubland and natural grassland was significantly higher than for other land uses, and cropland had the lowest SOC content. The effect of land use on the SOC content was more significant in the 0-10 cm soil layer than in other soil layers. For every type of land use, the SOC content decreased with soil depth. The highest SOC density (0-60 cm) in the study area was found in shrublandII (Hippophae rhamnoides), and the other land uses decreased in the SOC density as follows: natural grassland > shrublandI (Caragana korshinskii) > abandoned cropland > orchard > level ground cropland > terrace cropland > artificial grassland. Shrubland and natural grassland were the most efficient types for SOC sequestration, followed by abandoned cropland. The SOC stock (0-60 cm) in this study was 23,584.77 t with a mean SOC density of 4.64 (0-60 cm).     

红壤区土壤有机碳时间变异及合理采样点数量研究

相对于土壤有机碳(soil organic carbon,SOC)空间变异性及合理采样点数量的研究,其时间变异性及揭示特定时段SOC变化所需采样点数量的研究较少。选择红壤丘陵区的江西省余江县为研究区,分析了1982—2007年SOC含量的时间变异特征,并估算了揭示该时段SOC变化所需土壤采样点数量。结果表明,1982—2007年SOC含量均值由14.18增至16.27 g kg-1,增幅为14.74%,其变异系数则由0.22上升为0.44。各土地利用方式中,水田和林地SOC含量分别增加了2.93和3.12g kg-1,而旱地则降低了2.55 g kg-1;同时各利用方式的SOC含量变异系数均出现较大幅度的提高。基于两时段的全部样点,在95%和90%置信区间上,计算得到揭示该时段全县SOC时间变异所需的采样点数量分别为186和147。基于各土地利用方式的SOC变化,计算得到水田、旱地和林地所需采样点数量分别为68、44和144(95%置信区间)及54、34和112(90%置信区间);揭示旱地SOC变化所需采样点数量应为水田的60%以上,而林地所需样点则为水田的2倍以上。该研究结果可为红壤区SOC时间变异性及其调查采样提供参考。     

中国土壤有机碳分解特征研究初报

通过土壤样品的室内培养,运用三库一级动力学理论,对我国典型区域土壤有机碳分解特征进行了研究,结果表明:土壤有机碳分解均呈现前期分解快速和后期分解缓慢的特点,土壤有机碳分解的平衡点大概为2个月,之后的日均分解量变化非常小。我国东部4种地带性土壤有机碳分解速率随纬度的增加而递增。不同种植方式农田土壤有机碳分解速率:菜园>水田>旱地>果园。6个地区表层土壤有机碳含量范围为2.31~81.93 g/kg;活性碳含量范围为0.09~1.04 g/kg;缓效性碳含量范围为0.90~33.39 g/kg;惰效性碳含量范围0.92~47.85 g/kg。     

Using Cs and Pbex for quantifying soil organic carbon redistribution affected by intensive tillage on steep slopes

Studying on spatial and temporal variation in soil organic carbon (SOC) is of great importance because of global environmental concerns. Tillage-induced soil erosion is one of the major processes affecting the redistribution of SOC in fields. However, few direct measurements have been made to investigate the dynamic process of SOC under intensive tillage in the field. Our objective was to test the potential of ¹³⁷Cs and ²¹⁰Pb_ex for directly assessing SOC redistribution on sloping land as affected by tillage. Fifty plowing operations were conducted over a 5-day period using a donkey-drawn moldboard plow on a steep backslope of the Chinese Loess Plateau. Profile variations of SOC, ¹³⁷Cs and ²¹⁰Pb_ex concentrations were measured in the upper, middle and lower positions of the control plot and the plot plowed 50 times. ¹³⁷Cs concentration did not show variations in the upper 0–30 cm of soil whereas ²¹⁰Pb_ex showed a linear decrease (P < 0.05) with soil depth in the upper and middle positions, and an exponential decrease (P < 0.01) at the lower position of the control plot. The amounts of SOC, ¹³⁷Cs and ²¹⁰Pb_ex of sampling soil profiles increased in the following order: lower > middle > upper positions on the control plot. Intensive tillage resulted in a decrease of SOC amounts by 35% in the upper and by 44% in the middle positions for the soil layers of 0–45 cm, and an increase by 21% in the complete soil profile (0–100 cm) at the lower position as compared with control plot. Coefficients of variation (CVs) of SOC in soil profile decreased by 18.2% in the upper, 12.8% in the middle, and 30.9% in the lower slope positions whereas CVs of ¹³⁷Cs and ²¹⁰Pb_ex decreased more than 31% for all slope positions after 50 tillage events. ¹³⁷Cs and ²¹⁰Pb_ex in soil profile were significantly linearly correlated with SOC with R² of 0.81 and 0.86 (P < 0.01) on the control plot, and with R² of 0.90 and 0.86 (P < 0.01) on the treatment plot. Our results evidenced that ³⁷Cs and ²¹⁰Pb_ex, and SOC moved on the sloping land by the same physical mechanism during tillage operations, indicating that fallout ¹³⁷Cs and ²¹⁰Pb_ex could be used directly for quantifying dynamic SOC redistribution as affected by tillage erosion.     

县域农田土壤有机质空间变异及其影响因素分析

研究县域农田空间变异特征可以为培肥地力,增加作物产量提供指导。本文运用地统计学和 GIS相结合的方法,研究了四川省双流县土壤有机质的空间变异特征及其影响因素。结果表明： ①研究区域土壤有机质含量处于中等偏高水平,平均值为 29.72 g/kg,变异系数为 30.11%,属中等变异强度。②有机质变异函数的理论最佳模型为球状模型,块金值与基台值之比为12.67%,表明有机质含量具有强烈的空间相关性,空间相关距离为 91.10 km,普通Kriging插值表明土壤有机质含量呈现北部向东南部减少的趋势。③影响有机质空间变异的主要因素为土壤类型、地貌类型等结构性因子,而土地利用方式、施肥等随机性因子也对有机质空间变异产生重要影响,其中秸秆还田是有机质含量普遍升高的原因。     

Long-term effects of agronomic practices on the soil organic carbon sequestration in Chernozem

The study was based on data from selected long-term field trials established at the Experimental Fields of the Institute of Field and Vegetable Crops, Novi Sad (Serbia). The effect of tillage systems on SOC concentration and SOC stock was most pronounced at 0–10 cm depth. In a 0–40 cm soil layer, in a 7-year period, no-till (NT) sequestrated 863 kg SOC ha^?1 yr^?1 more compared to moldboard plow tillage (PT), while the effects of disc tillage (DT) and chisel tillage (CT) were not significantly different. Unfertilized three-crop rotation (CSW) compared to two-crop rotation (CW) enhanced SOC storage in a 0–30 cm soil layer by 151 kg C ha^?1 yr^?1 in a 56-year period. Within fertilized treatments, SOC concentration was highest under continuous corn (CC). Mineral fertilization (F) non-significantly increased the SOC stock compared to no fertilization in corn monoculture in a 32-year period. The incorporation of mineral fertilizers and harvest residues (F + HR) and mineral fertilizers and farmyard manure (F + FYM) sequestered 195 and 435 kg C ha^?1 yr^?1 more than the unfertilized plot, respectively, in a 0–30 cm soil layer, in a 35-year period. Irrigation did not significantly affect SOC sequestration.     

黑土农田土壤有机碳演变研究进展

在我国, 由于国家粮食安全的需要, 关注黑土、研究黑土的人越来越多, 尤其是黑土可持续利用及其与环境的关系已成为当今研究的热点问题。黑土研究领域中最活跃的部分是黑土农田土壤有机质(碳)的研究。基于此, 本文依据有关文献资料, 简述了我国黑土的分布、黑土开垦历史、农田土壤有机碳的演变及其在农业上的贡献, 系统分析了国内外农田土壤碳研究的方法及其进展, 指出了开展我国黑土农田土壤碳演变及其预测研究的现实意义及其潜在价值, 建议未来应侧重黑土农田土壤有机碳的变化与调控方面的研究, 即在黑土农田土壤有机碳的定向培育技术、指标体系和量化表征评估方法、预测模型等方面有所突破, 最终形成黑土农田土壤有机碳保护和利用的理论和方法。     

徐淮黄泛平原土壤有机质空间变异特征及主控因素分析

土壤有机质含量是估算土壤碳储量、评价土壤肥力和质量的重要指标,精确估算土壤有机质含量具有重要意义.本研究在徐淮黄泛冲积平原西北部选取了一个24 km×24 km方形区域为研究区,按照套合采样方法,采集了168个耕作层土样,测定分析土壤有机质含量和机械组成,运用地统计学方法和GIS技术研究了徐淮黄泛平原区表层土壤有机质含量的空间变异特征,利用方差分析和回归分析定量分析了区域内土壤有机质空间变异的影响因素.统计结果表明,研究区土壤有机质含量为21.80-7.43 gkg-1,属中等水平,变异系数为34.08％,属中等变异强度;地统计分析表明,研究区具有强烈的空间自相关性,结构变异占主导作用,各向异性显著,在45°方向上变异程度最剧烈,土壤有机质呈条带状分布,自东北向西南呈递减趋势;方差分析和逐步回归分析表明,土壤机械组成是研究区土壤有机质空间变异的主控因素,能够独立解释空间变异的64.9％,其次是土地利用、成土母质、土壤类型,四个因子对土壤有机质空间变异的综合解释为74.6％.     

黑碳添加对土壤有机碳矿化的影响

通过室内培养试验,向土壤中分别添加不同温度制备的黑碳,热解温度分别为350℃(T350)、600℃(T600)和850℃(T850),研究了黑碳添加对土壤有机碳矿化的影响。结果表明,不同温度条件制备的黑碳在15℃和25℃培养条件下,土壤CO2释放速率总的趋势是前期分解速率快,后期缓慢。在整个培养过程中(112天),随着培养时间的延长,土壤CO2释放速率下降趋势逐渐降低,CO2释放速率相对值的大小随着培养温度的的升高而增大。在不同温度培养条件下,添加黑碳后土壤CO2-C累计量均是T350>T600>T850,T350土壤CO2-C累计量最高分别为415.26 mg/kg和733.82 mg/kg。添加不同黑碳后,土壤有机碳矿化增加率存在极显著差异(p<0.01),表明不同温度制备的黑碳对土壤有机碳矿化的影响显著。     

SOCRATES—A simple model for predicting long-term changes in soil organic carbon in terrestrial ecosystems

The maintenance of soil organic carbon (SOC) in terrestrial ecosystems is critical for long-term productivity. Simulation models of SOC dynamics are valuable tools in predicting the impacts of climate on carbon storage and developing management strategies for the mitigation of greenhouse gas emissions, however, their utility is generally reduced due to need for specific data. The SOCRATES model is a simple process based representation of soil SOC dynamics in terrestrial ecosystems, which requires minimal data inputs and specifically designed to examine the impact of land use and land use change on soil carbon storage. SOCRATES was successful in predicting SOC change at eighteen long-term crop, pasture and forestry trials from North America, Europe and Australasia. These trials ranged from 8 to 86 years in duration, over a wide range of climates and soil types with annual changes in SOC ranging from −3.0 to 4.2%.     

典型喀斯特峰丛洼地土壤有机碳含量空间预测研究

我国西南喀斯特地区可能是全球水循环加强背景下一个重要的碳汇[1]。植被和土壤有机碳(SOC)的增加对于该地区整体碳汇的增加,以及这部分由水驱动的碳汇的增加具有极为重要的意义。然而峰丛洼地地区从景观到群落不同尺度水平上表现出的高度异质性,为该地区碳储量的估算和碳源/汇的评估带来很大困难,亟需探索有效方法对     

杭州湾南岸土壤有机碳空间异质性研究

应用地统计学与地理信息系统相结合的方法,研究了杭州湾南岸慈溪市域内不同土层(0～20、20～40、40～60、60～80、80～100、0～100 cm)的土壤有机碳含量空间变异特征。结果表明:研究区各土层土壤有机碳平均含量变化范围为3.49～7.95 g kg-1,变异系数介于54.51%～67.34%之间,属中等程度变异;地统计分析得出块金效应变化范围为0.141～0.372,表现为较强空间自相关性;自表层至底层最优半方差模型依次为高斯、指数、指数、高斯和球状模型;Kriging插值结果显示各土层土壤有机碳含量自滩涂向内陆呈递增趋势,其中0～20 cm土层土壤有机碳含量呈平行于海岸线的带状分布;土壤有机碳含量随剖面深度增加呈递减规律;不同土地利用方式和不同围垦时期均增加了土壤有机碳的空间变异性。从研究结果看,慈溪市土壤有机碳空间异质性主要由结构性因素引起,研究结果可为了解杭州湾南岸土壤有机碳分布特征提供参考。     

江淮丘陵区农田表层土壤有机碳空间变异——以定远县为例

以安徽省江淮丘陵区农业大县滁州市定远县为代表,运用统计学方法、地统计学方法和GIS技术研究了农田表层(0~20 cm)土壤有机碳(SOC)含量的空间分布及其影响因子。统计结果表明:研究区2011年SOC含量为(10.96±3.63)g/kg,变异系数为33.12%,属于中等变异程度。地统计分析结果表明,研究区SOC半方差模型为指数模型,存在强烈的空间自相关性,SOC含量在空间分布上表现为由东至西先递减后递增,大致呈带状分布。土壤颗粒组成和秸秆还田是影响SOC空间变异的主要因素。