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1.
S. Pulley H. Taylor J. M. Prout S. M. Haefele A. L. Collins 《Soil Use and Management》2023,39(3):1068-1081
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. 相似文献
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为探索不同碳源对土壤碳的提升作用,开展了不同碳源对烤烟生长季土壤碳平衡影响的研究,旨在为植烟土壤有机肥施用调控提供理论依据。试验设在四川省攀枝花市,以烤烟为供试作物进行田间小区试验。设对照(不施有机肥)、秸秆、农家肥、油枯、农家肥+油枯5个不同施肥处理,3次重复。采用VaisalaMI70土壤呼吸测量系统进行田间监测,并同时观测环境条件。对烤烟根系进行收集,测定土壤根系固碳量。研究结果显示,1)在烤烟生长季,植烟土壤呼吸动态呈倒"S"型的先下降后上升再下降的变化规律,施用有机肥增加了土壤呼吸强度,尤其是在有机肥施用初期。2)烤烟生长季碳排放量平均为385.84 kg·hm-2,不同处理碳排放量表现为对照293.11 kg·hm-2,秸秆396.9 kg·hm-2,农家肥363.36 kg·hm-2,油枯422.98 kg·hm-2,油枯+农家肥452.84kg·hm-2。3)不同碳源分解速率差异较大,生长季分解系数为0.22~0.42,秸秆和农家肥分解系数低于油枯。4)有机肥的施用对烤烟根系碳积累量的提升效果不明显,而各有机肥处理相比,农家肥以及农家肥与油枯混施相对于秸秆处理能够显著增加烤烟根系碳积累量。5)当地耕作模式下,整个生育期有56.42%的烤烟根系残留于土壤,可补偿土壤碳260.56 kg·hm-2,烤烟根系碳是常规施肥下土壤碳的主要来源。6)常规施肥下,单施化肥植烟土壤表现为碳源,有机无机配施下植烟土壤表现为碳汇。有机肥的施用能够提升土壤碳平衡,减少碳损失;采用农家肥与油枯混施也能够在一定程度上促进烤烟根系碳积累的提升。 相似文献
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不同有机物料对苏打盐化土有机碳和活性碳组分的影响 总被引：5，自引：1，他引：4
【目的】在大同盆地苏打盐化土上,研究不同有机物料对春玉米产量、土壤有机碳及活性碳组分的影响,明确土壤有机碳及活性碳组分与主要盐碱指标的相关关系,为苏打盐化土改良及有机物料资源化利用提供理论支撑。【方法】2016-2017年在山西省北部怀仁县开展田间定位试验,设对照(CK)、风化煤、生物炭、牛粪和秸秆5个处理,各处理有机物料施用量按照每年9000 kg/hm^2等有机碳投入量折算,收获时对春玉米进行测产。2017年春玉米收获后,采集土壤样品测定土壤有机碳总量(SOC)和水溶性有机碳(WSOC)、易氧化有机碳(EOC)、轻组有机碳(LFOC)含量,分析土壤活性碳组分占有机碳的比例、土壤有机碳及活性碳组分与盐碱指标之间的关系。【结果】与CK相比,生物炭和秸秆处理春玉米产量无明显差异,而风化煤和牛粪处理春玉米产量则分别显著提高30.2%和30.3%。添加有机物料促进了0-20 cm土层SOC累积,其中以风化煤和牛粪处理效果最佳,较CK分别提高47.6%和36.1%。在有机碳组分方面,风化煤和牛粪处理提高WSOC、EOC含量的效果显著高于生物炭、秸秆处理;风化煤、牛粪和秸秆处理的LFOC含量显著高于生物炭处理。四类有机物料处理的WSOC占总有机碳的比例差异不显著,牛粪处理的占比显著高于CK。EOC占总有机碳的比例以牛粪处理最高,风化煤次之,且二者均显著高于CK处理;LFOC占总有机碳的比例则表现为秸秆、牛粪>风化煤、生物炭> CK。此外,添加有机物料能有效降低0-20 cm土层土壤pH、电导率(EC)和碱化度(ESP),其中以风化煤和牛粪处理降幅最大。相关分析表明,土壤SOC与pH、EC和ESP呈显著负相关。【结论】通过有机物料改良效果比较,发现牛粪和风化煤处理能促进苏打盐化土有机碳累积,提高可溶性、易氧化态及轻组有机碳组分在总有机碳中的占比,降低土壤pH、EC和ESP,明显提高春玉米产量。因此,风化煤和牛粪是山西北部苏打盐化土良好的改良剂。 相似文献
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不同秸秆还田模式对土壤有机碳及其活性组分的影响 总被引：43，自引：9，他引：34
为了探讨不同秸秆还田模式对土壤有机碳(total organic carbon,TOC)及活性碳组分的影响,设置了秸秆不还田(CK)、秸秆直接还田(CS)、秸秆转化为食用菌基质,出蘑后菌渣还田(CMS)和秸秆过腹还田(CGS)4种还田模式。通过田间小区试验,研究了不同秸秆还田模式下,土壤有机碳及活性组分的变化规律。结果表明不同秸秆还田模式均提高了土壤有机碳含量,但不同还田模式下土壤有机碳含量差异不显著(P0.05),和CK相比,CS、CMS和CGS处理下,土壤有机碳质量分数分别增加9.0%、23.9%和26.7%。不同秸秆还田模式也提高了土壤活性碳组分含量。在不同秸秆还田模式下,土壤溶解性有机碳(dissolved organic carbon,DOC)含量表现为CSCMSCGSCK,且不同处理间差异显著(P0.01)。和CK相比,CS、CMS和CGS处理下,土壤DOC质量分数分别增加64.6%、29.4%和8.9%。土壤微生物量碳(microbial biomass carbon,MBC)含量表现为CMSCGSCSCK,且差异显著(P0.05)。和CK相比,CS、CMS和CGS处理下,土壤MBC质量分数分别增加28.9%、84.7%和59.3%。土壤易氧化态碳(easily oxidizable carbon,EOC)含量表现为CMSCSCGSCK,且差异显著(P0.01)。和CK相比,CS、CMS和CGS处理下,土壤EOC质量分数分别增加24.1%、55.7%、和9.3%。不同秸秆还田模式显著影响土壤活性碳组分在总有机碳中占的比例,改变土壤有机碳质量。在不同秸秆还田模式下,DOC/TOC表现为CSCMSCKCGS、MBC/TOC表现为CMSCGSCSCK、EOC/TOC表现为CMSCSCKCGS,且不同处理间均差异显著(P0.01)。从提高土壤质量角度,推荐秸秆-菌渣还田模式,在该模式下,土壤MBC/TOC和EOC/TOC均最大,土壤碳素有效性高、易于被微生物利用,有利于作物生长。从提高土壤固碳角度,推荐秸秆过腹还田模式,在该模式下,土壤DOC/TOC最小,且土壤有机碳含量最高,有利于碳的固定和保存。该研究结果可为秸秆合理高效利用、改善农业土壤碳库质量提供参考。 相似文献
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Ultrasonic dispersion is a prevalent tool for soil fractionation. It is widely ignored that variation in ultrasonic power might lead to significantly different dispersion. We evaluated the effect of power variation with constant energy on the fine fraction mass, its organic C content and quality. All parameters increased significantly with power. The term “stable aggregates” as used in fractionation schemes cannot be defined by ultrasonic energy alone but power needs to be standardized, too. 相似文献
6.
Maria Regina Gmach Klaus Kaiser Maurício Roberto Cherubin Carlos Eduardo Pellegrino Cerri Izaias Pinheiro Lisboa Ana Luisa Soares Vasconcelos Marcos Siqueira‐Neto 《Soil Use and Management》2021,37(1):126-137
Global demand for bioenergy increases interest in biomass‐derived fuels, as ethanol from sugarcane straw. However, straw is the main carbon source to soil and its removal reduces C input, affecting active fractions (dissolved organic carbon, DOC) and C storage. To quantify the effects of straw removal on DOC and C stocks, we built lysimeter system using soil (Rhodic Kandiudox) from sugarcane field. We evaluated four soil depths (1, 20, 50 and 100 cm) and four straw removal rates: no removal NR, medium MR, high HR and total TR, leaving 12, 6, 3 and 0 Mg/ha on the soil surface, respectively. After rainfall, drainage water was collected and analysed for DOC content. Soil C stocks were determined after the 17‐month. Total DOC released at 1‐cm depth amounted to 606, 500, 441 and 157 kg/ha in NR, MR, HR and TR, respectively. Net‐DOC suggests straw as the main source of DOC. Most of DOC in NR (50%) was retained within the 1–20 cm layer, resulting in higher C stock (10 Mg/ha) in the topsoil. In HR and MR, DOC retention was higher within 20–50 cm, suggesting differences in DOC composition. DOC in TR was 40% higher at 20 cm than at 1 cm, indicating C losses from topsoil. Low concentrations of DOC were found at 100‐cm depth, but representing 30% in TR. Straw removal for bioenergy production is sustainable, but we should leave at least 3 Mg/ha of straw to ensure DOC production and soil C storage, taking account the DOC contribution to key soil functions. 相似文献
7.
为了探讨侵蚀条件下生物结皮对坡面土壤碳氮的影响,通过野外小区对比试验与室内分析相结合,研究有、无生物结皮坡面土壤有机质、全氮、硝态氮和铵态氮的分布特征。结果表明：生物结皮对坡面土壤碳氮积累具有重要意义,同一坡位下,土壤有机质、全氮和硝态氮含量在0～20cm剖面上均明显表现为生物结皮大于无结皮。总体来看,生物结皮对土壤碳氮的影响主要集中在0～10cm土层,与无结皮相比,土壤有机质、全氮、硝态氮和铵态氮平均储量分别增加了44.7%、18.2%、39.2%和4.33%。生物结皮能显著增加0～2和2～5cm土壤硝态氮含量（P<0.05）,这除了生物结皮对土壤养分的保蓄效应外,还可能与生物结皮向土壤释放硝态氮有关。由于铵态氮流失特征不同于硝态氮,加之生物结皮可能会利用或释放铵态氮,使生物结皮对其影响表现出无明显规律性。相关分析表明,土壤有机质与全氮、硝态氮和铵态氮均达到了极显著或显著的正相关关系（P<0.01或P<0.05）。综上所述,侵蚀环境下生物结皮发挥着重要的固土蓄肥功能,这对研究区退化生态系统的恢复和重建具有积极的意义。 相似文献
8.
Yiming Zhao Shan Lin Yanni Liu Guoyuan Li Jinggou Wang Klaus Butterbach-Bahl 《Soil Use and Management》2020,36(3):439-448
Solar vegetable greenhouse soils show low soil organic carbon content and thus also low rates of soil respiration. Processing vegetable residues to biochar and mixing biochar with maize straw might improve soil respiration and increase soil organic carbon stocks, while preventing the spread of soil-borne diseases carried by vegetable residues. In an incubation experiment, we tested how additions of maize straw (S) and biochar (B) added in varying ratios (100S, 75S25B, 50S50B, 25S75B, 100B and 0S0B (control)) affect soil respiration and fraction of added C remaining in soil. Daily CO2 emissions were measured over 60 days incubation, the natural abundance of 13C in soil and in the added biochar and maize straw were analysed. Our result shows that (a) soil CO2 emissions were significantly increased compared to soil without the straw additions, while addition of biochar only decreased soil respiration; (b) cumulative CO2 emissions decreased with increasing ratio of added biochar to maize straw; (c) the abundance of soil 13C was significant positively correlated with cumulative CO2 emissions, and thus with the ratio of straw addition. Our results indicate that incorporation of maize straw in greenhouse soils is a meaningful measure to increase soil respiration and to facilitate greenhouse atmosphere CO2 limitation while producing vegetables. On the other hand, additions of biochar from vegetable residues will increase soil organic carbon concentration. Therefore, the simultaneous application of maize straw and biochar obtained from vegetable residues is an effective option to maintain essential soil functions for vegetable production in sunken solar greenhouses. 相似文献
9.
施肥对土壤有机碳含量及碳库管理指数的影响 总被引：16，自引：0，他引：16
在华北夏玉米生产体系中,采用田间试验,研究了不同施肥措施下（不施肥、单施有机肥、推荐施肥、习惯施肥和单施化肥）,土壤有机碳含量、活性有机碳含量和碳库管理指数的变化。结果表明:与不施肥相比,单施有机肥土壤有机碳和活性有机碳含量分别增加 11.68%,21.71%。推荐施肥和习惯施肥土壤有机碳含量分别增加 6.57%,7.58%,活性有机碳含量分别增加 8.53%,4.26%。单施化肥土壤有机碳与活性有机碳含量均没有显著增加;施有机肥和推荐施肥土壤碳库管理指数比不施肥分别高 31.79,13.01。单施化肥土壤碳库管理指数没有显著变化;土壤活性有机碳与总有机碳、碳库管理指数、玉米子粒产量均存在极显著相关关系。碳库管理指数与玉米子粒产量极显著相关,能够指示土壤生产力的变化。可见在当地土壤肥力条件下,施有机肥或有机无机适当配施能提高土壤有机碳含量和土壤碳库管理指数,有利于改善土壤质量,提高土壤肥力。 相似文献
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11.
Research information from a systematic planned study on the effects of vehicular passages and axle load on soil carbon dioxide (CO2) fluxes and soil carbon (C) sequestration under long‐term NT farming is scanty. Therefore, the present study was conducted on an on‐going 20‐year experiment to assess the impacts of variable vehicular passages of a low axle load on soil CO2 emission and soil C sequestration from a no‐till (NT) managed corn (Zea mays L.)–soybean (Glycine max Linneo) rotation in comparison with that a soil under woodlots (soils under natural wooded plantation). The experimental treatment consisted of an empty wagon [0 Mg load for compaction (C‐0; control)] compared with 2 (C‐2) and 4 (C‐4) passages of 2.5 Mg water wagon axle load, applied to the entire plot every year during April/May for 20 consecutive years. Soil samples were obtained in November 2016 to determine the effects of various vehicular passages on C and nitrogen (N) contents and CO2 emissions. Soil CO2 fluxes were measured from November 16, 2016, to May 30, 2017, on the bi‐weekly (November to December and April to May) and monthly (January to March) basis by using high‐density polyvinyl chloride static gas chambers. The soil CO2 fluxes ranged from –1.05 to 9.03 g CO2 m?2 d?1. The lowest soil CO2 fluxes were observed in December coinciding with the minimum soil temperature. In general, daily soil CO2 fluxes were higher under C‐0 than those under other treatments. Vehicular traffic and axle load reduced the cumulative emission of CO2 by 22.6 and 29.8% under C‐2 and C‐4, respectively, compared with that under C‐0 (6.09 Mg ha?1). Soil and air temperatures had a significant positive correlation with the diurnal fluxes of soil CO2 in all the treatments except that under C‐4. Electrical conductivity, soil C and N contents and pools did not differ significantly among the treatments. Further, 2 to 4 passages of vehicles with 2.5 Mg of axle load decreased the soil CO2 emission on Crosby silt loam under NT as compared to that under the control. Therefore, continuous cultivation of row crops with moderate trafficking under NT and residue retention is recommended, and it also reduces the potential of soil CO2 emission while improving the soil organic C pools of well‐drained soils of Central Ohio. 相似文献
12.
长期不同施肥和土地利用方式对塿土耕层碳储量的影响 总被引：1，自引：1，他引：0
利用土20年长期肥料定位试验研究了不同土地利用方式和施肥对土壤有机碳和无机碳储量变化的影响。试验包括休闲（Fallow, FL）、 撂荒（Setaside, SL）、 不施肥（CK）、 单施氮（N）、 氮钾（NK）、 磷钾（PK）、 氮磷（NP）、 氮磷钾（NPK）、 氮磷钾配合秸秆还田（SNPK）、 氮磷钾配合低量有机肥（M1NPK）和氮磷钾配合高量有机肥（M2NPK）11个处理。结果表明,CK和 FL 处理等质量耕层土壤有机碳储量仍维持在试验前水平,NP和 SL 处理显著提高了耕层土壤有机碳储量,年均增加分别达到 347 kg/hm2 和518 kg/hm2, 此4个处理等质量耕层土壤无机碳储量均较试验开始前（Initial soil, IniS）显著下降,尤其是NP处理显著低于其它3个处理。与IniS和CK相比,除NK处理外的所有施肥处理均显著地提高了等质量耕层土壤有机碳储量,其大小顺序为 M2NPKM1NPKSNPKNPKNPPKN,最大年均增加量为M2NPK 944 kg/hm2,最小为N 127 kg/hm2。施肥处理除PK和M2NPK处理外,其它处理等质量耕层土壤无机碳储量均较试验前明显降低,可能是由于土壤酸化所致。PK和M2NPK处理无机碳储量能够维持不下降,表明土壤无机碳和有机碳在适合条件下可能有某种关系。试验结果还显示,长期试验20年除M1NPK和M2NPK处理外,其它处理耕层土壤容重均明显高于试验开始前,表明等质量土壤碳储量与等深度碳储量相比可以更好地反映土壤碳的变化。 相似文献
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基于30年水稻土长期施肥定位试验,在保证原有定位试验正常开展的前提下,将部分化肥处理变更为有机肥处理(或反之),通过观测一年水稻轮作周期内不同处理甲烷(CH_4)排放通量季节性变化,探讨不同肥力水稻土中外源有机碳及土壤有机碳含量对田间CH_4排放的影响。结果表明:施化肥处理和有机肥处理,水稻土全年CH_4累积排放量范围分别为1.73~4.72和35.09~86.60 g·m~(-2)。有机肥处理改施化肥后,田间土壤CH_4的排放量显著降低;化肥处理改施有机肥或有机肥处理增施有机肥后,田间土壤CH_4的排放量显著提高。外源有机碳的输入量是田间土壤CH_4年排放量的决定性因素,外源有机碳输入量(x)与水稻土CH_4年累积排放量(y)之间满足直线方程:y=0.087 7 x+3.265 7(R~2=0.965 9,n=21)。土壤有机碳同样也是影响稻田CH_4排放的因素,在不同有机碳水平的水稻土上施用等量相同化肥或有机肥,土壤有机碳含量高的水稻土都更有利于CH_4的产生。单施化肥稻田土壤CH_4排放的最主要碳源是土壤有机碳,有机碳含量(x)和水稻土CH_4年累积排放量(y)之间的指数方程:y=0.162 4 e~(0.162 2 x)(R~2=0.940 6,n=9)。有机肥可促进土壤有机碳分解释放CH_4,土壤有机碳含量相同的条件下,高量有机肥比常量有机肥的土壤有机碳分解比率高0.65%,等量相同有机肥但土壤有机碳含量不同的条件下,土壤有机碳分解比率无显著差异;同样,土壤有机碳也可促进有机物料碳分解释放CH_4,在常量有机肥或高量有机肥处理中,土壤有机碳含量高者比低者的有机物料碳分解比率分别多出3.57%和2.34%。 相似文献
14.
长期不同施肥下黑土与灰漠土有机碳储量的变化 总被引：6，自引：1，他引：5
采用长期试验,研究了20年不同施肥下1 m深黑土与灰漠土有机碳含量与碳储量的剖面变化。结果表明,单施化肥和不施肥对黑土1 m土层有机碳储量没有显著影响,但灰漠土略有降低。有机肥配施化肥能显著提高土壤有机碳含量和储量。高量有机肥配施化肥（NPKM2）能提高020 cm和2040 cm土层土壤有机碳含量,黑土分别提高56.6%和49.6%、灰漠土提高143.1%和46.9%;常量有机无机配施（NPKM）效果较差,增幅分别为黑土35.1%和35.3%,灰漠土80.2%和4.1%。两种土壤1 m土体的有机碳储量,NPKM2处理分别提高了C 30.7 t/hm2与C 40.6 t/hm2。显然,有机无机肥配施可以显著提高1 m深土体中有机碳储量,主要是由于提高了040 cm土层土壤有机碳含量。 相似文献
15.
Haiming Tang Xiaoping Xiao Wenguang Tang Chao Li Ke Wang Weiyan Li 《Communications in Soil Science and Plant Analysis》2018,49(16):1976-1989
The effects of manure and chemical fertilizer on soil bulk density, soil organic carbon (SOC), and the role of carbon management index (CMI) in soil quality evaluation were studied under a double-cropping rice system in a long-term experiment. The experiment included five fertilizer treatments: without fertilizer input (CK), chemical fertilizer alone (MF), rice straw residue plus chemical fertilizer (RF), 30% organic matter plus 70% chemical fertilizer (LOM), and 60% organic matter plus 40% chemical fertilizer (HOM). RF, LOM, HOM treatments increased SOC content relative to MF treatment in the paddy fields at 0–20 cm. RF, LOM, HOM treatments were more effective for increasing CMI, lability index, lability of C, and SOC stocks, as compared with MF treatment. Based on rice grain yield and carbon storage, integrated fertilization of chemical fertilizer and organic manure proved to be the most effective practices for improving crop productivity and SOC sequestration. 相似文献
16.
研究长期不同施肥处理对3种旱作土壤(黑土、潮土和红壤)及1种水田土壤(水稻土)活性有机碳含量(LOC)及碳库管理指数(CMI)的影响,为优化施肥管理措施提供科学依据。结果表明:水田土壤总有机碳含量(TOC)和LOC含量高于旱作土壤。单施化肥(NPK),旱作3种土壤TOC、LOC较不施肥对照(CK)显著增加,而水田较CK无显著差异。化肥配施秸秆处理(NPKS),旱作和水田土壤TOC、LOC、活性有机碳占总有机碳的比例(LOC/TOC)及CMI均显著增加,潮土TOC和LOC含量增加最多,增加比例分别为37.6%和66.9%。化肥配施有机肥处理(NPKM),旱作和水田土壤的TOC、LOC、LOC/TOC及CMI均显著增加,其中黑土增加比例最大,分别为90.3%、140.9%、5.1%及277%。旱作和水田土壤的活性有机碳及碳库管理指数均对施肥响应敏感,具有相对一致的响应特征,即长期有机无机肥配施能显著提高土壤活性有机碳含量及碳库管理指数,且效果优于化肥配施秸秆和单施化肥处理。 相似文献
17.
不同地表覆盖栽培对旱地土壤有机碳、无机碳和轻质有机碳的影响 总被引：10，自引：1，他引：9
通过田间长期定位试验,分层采集冬小麦-休闲种植体系0—40 cm土层的土样,研究了常规、地表覆膜和覆草栽培对土壤有机碳、无机碳和轻质有机碳的影响。结果表明,覆膜或覆草可以显著增加地上部小麦生物量和子粒产量。不同地表覆盖对0—40 cm土层的无机碳含量和分布无显著影响,但与常规栽培相比,地表覆膜使0—5 cm土层的有机碳含量显著降低,0—40 cm各土层轻质有机碳表现出明显降低趋势,平均降低 C 6.1~74.5 mg/kg;地表覆草却表现出明显增加土壤轻质有机碳的趋势,0—5,5—10,10—20 cm土层的轻质有机碳含量分别增加C 235.2、190.0和144.9 mg/kg,相当于常规的38.7%,32.9%和34.5%。同时,覆草栽培还表现出降低0—10 cm土层轻质有机质含碳量的趋势,并使0—20 cm土层轻质有机碳占有机碳的比例显著高于常规栽培和地表覆膜处理。可见,地表长期覆膜不利于旱地土壤有机碳累积,覆草不仅可以增加表层土壤的轻质有机碳累积,还可改善土壤碳氮组成。 相似文献
18.
黄土高原沟壑区不同年限苹果园土壤碳氮磷变化特征 总被引：10，自引：2，他引：8
管理措施是影响土壤质量演变的重要因素.分析和讨论了5、10、15年苹果园耕层(0―20 cm)和0―200 cm土壤有机碳、全氮、全磷、有效磷和硝态氮含量及其影响因素。结果表明,5年、10年和15年的塬面苹果园表层土壤有机碳依次为7.5、6.7和6.7 g/kg;全氮依次为0.94、0.85和0.83 g/kg;但土壤全磷和速效磷含量随着种植年限而增加,与5年苹果园相比,塬面10年苹果园土壤全磷、速效磷含量分别提高了11%、60%,并且磷素的变异性随年限而增加。坡地10年、15年和20年苹果园土壤有机碳依次为6.3、6.2 和6.5 g/kg,全氮依次为0.76、0.76 和0.81 g/kg;与10年苹果园相比,15年苹果园土壤全磷、速效磷含量分别提高了20%、28%。土壤剖面0―80 cm内不同土地利用方式土壤碳、氮、磷含量随土层加深而降低,80 cm以下不同利用条件苹果园土壤碳、磷含量差异不大,氮素含量在土壤100 cm下随苹果园种植年限增加而增加。 相似文献
19.
Restoration of degraded soils is a development strategy to reduce desertification, soil erosion and environmental degradation, and alleviate chronic food shortages with great potential in sub‐Saharan Africa (SSA). Further, it has the potential to provide terrestrial sinks of carbon (C) and reduce the rate of enrichment of atmospheric CO2. Soil organic carbon (SOC) contents decrease by 0 to 63 per cent following deforestation. There exists a high potential for increasing SOC through establishment of natural or improved fallow systems (agroforestry) with attainable rates of C sequestration in the range of 0·1 to 5·3 Mg C ha−1 yr−1. Biomass burning significantly reduces SOC in the upper few centimeters of soil, but has little impact below 10 to 20 cm depth. The timing of burning is also important, and periods with large amounts of biomass available generally have the largest losses of SOC. In cultivated areas, the addition of manure in combination with crop residues and no‐till show similar rates of attainable C sequestration (0 to 0·36 Mg C ha−1 yr−1). Attainable rates of SOC sequestration on permanent cropland in SSA under improved cultivation systems (e.g. no‐till) range from 0·2 to 1·5 Tg C yr−1, while attainable rates under fallow systems are 0·4 to 18·5 Tg C yr−1. Fallow systems generally have the highest potential for SOC sequestration in SSA with rates up to 28·5 Tg C yr−1. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
20.
菜地土壤有机碳分级以及总量变化的动态特征研究 总被引：1，自引：0，他引：1
Fertilisers significantly affect crop production and crop biomass inputs to soil organic carbon（SOC）. However, the long-term effects of fertilisers on C associated with aggregates are not yet fully understood. Based on soil aggregate and SOC fractionation analysis, this study investigated the long-term effects of organic manure and inorganic fertilisers on the accumulation and change in SOC and its fractions, including the C concentrations of free light fraction, intra-aggregate particulate organic matter（POM） and intra-aggregate mineral-associated organic matter（MOM）. Long-term manure applications improved SOC and increased the concentrations of some C fractions. Manure also accelerated the decomposition of coarse POM（cPOM） into fine POM（fPOM） and facilitated the transformation of fPOM encrustation into intra-microaggregate POM within macroaggregates. However, the application of inorganic fertilisers was detrimental to the formation of fPOM and to the subsequent encrustation of fPOM with clay particles, thus inhibiting the formation of stable microaggregates within macroaggregates. No significant differences were observed among the inorganic fertiliser treatments in terms of C concentrations of MOM, intra-microaggregate MOM within macroaggregate（imMMOM） and intra-microaggregate MOM（imMOM）. However, the long-term application of manure resulted in large increases in C concentrations of MOM（36.35%）, imMMOM（456.31%） and imMOM（19.33%） compared with control treatment. 相似文献