,, 高明,, 黎嘉成, 徐国鑫, 王富华, 李娇, 陈仕奇西南大学资源环境学院,重庆 400715Effects of Combined Application of Various Organic Materials and Chemical Fertilizer on Soil Nitrogen Formation and Greenhouse Gas Emission Under Equal Nitrogen Rates from Purple Soil
HUANG Rong,, GAO Ming,, LI JiaCheng, XU GuoXin, WANG FuHua, LI Jiao, CHEN ShiQiCollege of Resources and Environment, Southwest University, Chongqing 400715通讯作者:
责任编辑: 李云霞
收稿日期:2018-04-2接受日期:2018-08-10网络出版日期:2018-11-01
| 基金资助: |
Received:2018-04-2Accepted:2018-08-10Online:2018-11-01
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黄容, 高明, 黎嘉成, 徐国鑫, 王富华, 李娇, 陈仕奇. 有机物料等氮量施用对紫色土氮形态及温室气体排放的影响[J]. 中国农业科学, 2018, 51(21): 4087-4101 doi:10.3864/j.issn.0578-1752.2018.21.008
HUANG Rong, GAO Ming, LI JiaCheng, XU GuoXin, WANG FuHua, LI Jiao, CHEN ShiQi.
0 引言
【研究意义】全球气候变暖是当今世界面临的重要挑战,CO2、CH4和N2O等温室气体（GHG）浓度的变化是影响气候变暖的重要驱动因子[1]。农田生态系统是温室气体重要的排放源。我国土壤施肥（尤其是氮肥）量大,菜地土壤的氮肥施用量是其他农作物土壤的4倍多[2],但氮肥利用率约30%,剩余的氮肥或转为温室气体,或转为硝态氮等进入水体成为污染源[3];同时过多的氮投入会限制未来农田的碳封存[4]。据估算,菜地土壤因施肥产生的N2O直接排放量高达6.7万吨[5]。作物可以择优吸收土壤中不同的氮组分,其中矿质氮是作物吸收的最主要氮源,可以被作物直接吸收利用[6]。我国每年的农业废弃物产量大且品种多,包括秸秆、菇渣、牛粪等;但大部分以焚烧、直接丢弃或流入水体的形式流失,不仅污染环境而且也造成GHG排放[7]。农业废弃物富含氮、磷、钾等营养元素[8],将其归还到田间,不仅可以替代部分化肥,减少化肥的施用,提高氮素利用率,而且对改善因施用化肥（尤其是氮肥）和农业废弃物处理所带来的生态环境问题,控制化肥投入以缓解农田土壤温室气体排放具有重要的意义。【前人研究进展】秸秆、菌渣、生物质炭、畜禽粪便是重要的农业资源,其还田虽能增加农田固碳,提高土壤质量,但有机物料成分不同会影响其施用到农田后的温室气体排放[9]。有研究表明,秸秆与化肥减量30%配施处理能降低土壤CO2和CH4排放,缓解温室气体的增温潜势,但对土壤N2O减排效果不显著[10];秸秆配施70%—80%的化肥,可以有效提高土壤碱解氮含量[11]。段鹏鹏等[12]研究表明,氮肥与有机肥配合施用能显著提高矿质氮的含量。菌渣作为农业加工系统的产物,其富含营养物质,石生伟等[13]研究表明,腐熟的菌渣配施化肥后,不仅可以大幅度降低稻田的整体温室效应,而且能够替代部分化肥,保持高产。而李柘锦等[7]对比几种有机物料还田发现,菌渣+无机肥处理较无机肥处理增加了土壤温室气体排放,且全球增温潜势高于秸秆处理。张斌等[14]连续两年观测了生物质炭配施氮肥的管理对温室气体排放影响发现,高量施用生物质炭可以增加土壤氮素,显著降低稻田CH4和N2O痕量温室气体排放的综合温室效应;同时范靖尉等[15]研究表明在集约化农田减氮20%,不仅对作物的产量无显著影响,而且能降低农田土壤温室气体排放,但生物质炭对温室气体的排放与气候条件、土壤类型、生物质炭种类及其施用年限等因素密切相关[15,16,17]。张旭博等[18]研究表明,秸秆的可溶性碳含量高,能较快被微生物利用,增强土壤呼吸,因此动物类有机肥（猪粪、牛粪等）较秸秆类有机物料能较快提高土壤碳、氮源的有效性,增强微生物活性,促进养分转化和释放,显著降低了CO2释放量。【本研究切入点】尽管,有机物料还田可以替代部分化肥,减少化肥的施用量,但是有机物料还田对农田土壤温室气体排放的研究结果存在不完全一致性[19,20,21,22],且研究对象主要集中在水田,对旱地土壤尤其是菜地土壤的研究较少。不同有机物料（如秸秆、动物有机肥等）还田后,对土壤氮形态的影响也不同;且施入不同有机物料后的温室气体排放量尚不明确[18]。【拟解决的关键问题】本文拟通过田间试验,对蔬菜连作种植模式的菜地进行了不同有机物料等氮量施用处理下的土壤氮形态分布及土壤温室气体排放观测研究,以期为合理利用农业资源,且通过控制化肥投入以减少旱地农田温室气体排放提供科学依据。1 材料与方法
1.1 研究区概况及试验材料
试验地点位于重庆市北碚区“国家紫色土土壤肥力与肥料效益长期监测基地”,海拔266.3 m,年平均气温18.3℃。最高和最低气温平均为28.7℃和7.7℃,≥10℃的积温6 006℃,年降雨量1 086.6 mm,年日照时数1 276.7 h,属于亚热带季风气候。试验土壤为侏罗纪沙溪庙组紫色泥页岩发育形成的紫色土,中性紫色土亚类,灰棕紫泥土属,是重庆四川紫色土区分布最广的一种土壤。其基本理化性质为：有机碳含量11.12 g·kg-1,碱解氮83.02 mg·kg-1,速效磷44.10 mg·kg-1,速效钾208.75 mg·kg-1,pH 为5.8。试验用秸秆为玉米秸秆,取自试验基地农田,其有机碳含量338.8 g·kg-1,氮含量10.1 g·kg-1,C/N=33.9,磷含量2.2 g·kg-1,钾含量1.3 g·kg-1,经晒干后粉碎机粉碎成5—10 cm颗粒,备用。试验用菌渣取自重庆梨木食用菌专业合作社,为收获金针菇后的废弃菌棒,经晒干粉碎后还田,其有机碳含量391.2 g·kg-1,氮含量11.2 g·kg-1,C/N=34.9,磷含量1.9 g·kg-1,钾含量0.5 g·kg-1。试验用生物质炭以油菜秸秆为原料,500℃高温厌氧条件下热解2 h烧制,由四川省久晟农业有限农业公司提供,其有机碳含量625.8 g·kg-1,氮含量4.4 g·kg-1,C/N=142.2,磷含量1.0 g·kg-1,钾含量10.4 g·kg-1。试验用牛粪采自重庆北碚澄江上马台村天友乳业,经晒干粉碎后还田,其有机碳含量428.8 g·kg-1,氮含量为21.2 g·kg-1,C/N=20.2,磷含量5.9 g·kg-1,钾含量1.2 g·kg-1。1.2 试验设计
试验共设置6个处理：对照即不添加化肥和物料（CK）、常规化肥（F）、12 000 kg·hm-2秸秆配施化肥（SF）、9 000 kg·hm-2菌渣配施化肥（MF）、10 000 kg·hm-2生物质炭配施化肥（BF）、20 000 kg·hm-2牛粪配施化肥（CF）。每个处理3次重复,采用随机区组排列在18个2 m×1 m能独立排灌的微区内,各个微区的水肥管理均相同。试验于2016年10月开始,共种植3季蔬菜（莴笋、卷心菜、辣椒）,施用两次有机物料,分别在种植莴笋和辣椒前将秸秆、菌渣、生物质炭、牛粪均匀撒覆在土壤表面并进行翻耕,深度为30—40 cm,同时对照CK和常规处理F也进行同样的翻耕。各作物（莴笋、卷心菜、辣椒）的氮、磷、钾肥的常规施用量按《中国主要作物施肥指南》[23]化肥施用量,有机物料与化肥配施处理按照《中国主要作物施肥指南》的常规使用量的基础上减去有机物料中的含氮、磷,钾量,再补施一定量的化肥,各季作物栽培方式和灌溉、除草等田间管理按照当地习惯进行,灌溉时间通常在施肥和追肥后,以及土壤含水量较低的时候,每个处理均进行灌溉。氮、磷、钾化肥品种分别为尿素（N46%）、过磷酸钙（P2O512%）、氯化钾（K2O 60%）。具体种植及施肥方式见表1。
Table 1
表1
表1种植及施肥情况
Table 1
| 蔬菜 Vegetable | 常规需氮(N)量 Conventional nitrogen requirement (kg·hm-2) | 常规需磷(P2O5)量 Conventional phosphate requirement (kg·hm-2) | 常规需钾(K2O)量 Conventional potassium requirement (kg·hm-2) | 种植及施肥情况 Planting and fertilization |
|---|---|---|---|---|
| 莴笋 Lettuce | 300 | 90 | 150 | 2016年10月20日施入有机物料并翻耕,10月27日移栽莴笋苗,10月30日施基肥（氮肥60%,磷肥和钾肥一次性施入）,12月9日追肥（氮肥40%）,2017年1月9日收获莴笋 Organic material was incorporated into soil and plowed on 20 October 2016. The lettuce was transplanted on 27 October 2016. A total of P and K fertilizers were applied as basis along with 60% of N fertilizer on 30 October 2016, and 40% of N fertilizer was applied on 9 December 2016. The lettuce was harvested on 9 January 2017 |
| 卷心菜 Cabbage | 300 | 70 | 300 | 2017年1月10日施基肥（氮肥40%,钾肥40%,磷肥一次性施入）,1月11日移栽卷心菜苗,2月21日第一次追肥（氮肥30%,钾肥30%）,3月27日第二次追肥（氮肥30%,钾肥30%）,5月4日收获卷心菜 A total of P fertilizer, 40% of N fertilizer and 40% of K fertilizer was applied as basis on 10 January 2017. The cabbage was transplanted on 1 January 2017. The remaining N and K fertilizers were split into two parts of the same amount and top-dressed on 21 February and 27 March 2017, respectively. The cabbage was harvested on 4 May 2017 |
| 辣椒 Chili | 300 | 80 | 150 | 2017年5月5日施入有机物料并翻耕,5月10日施基肥（氮肥50%,钾肥50%,磷肥一次性施入）,5月11日移栽辣椒苗,6月19日追肥（氮肥50%,钾肥50%）,7月20日、8月18日、9月14日收获辣椒 Organic material was incorporated into soil and plowed on 5 May 2017. A total of P fertilizer, 50% of N fertilizer and 50% of K fertilizer was applied as basis on 10 May 2017. The chili was transplanted on 11 May 2017. The remaining of N and K fertilizers were applied on 19 June 2017. The chili was harvested on 20 July, 18 August and 14 September 2017, respectively |
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1.3 试验方法
采用静态箱-气相色谱法测定菜地土壤温室气体排放通量[24]。采样箱材质为不锈钢材料,由底座和顶箱两部分组成,底座（横截面为50 cm×50 cm）长期固定于田间,翻耕时将底座取出,翻耕结束后重新将底座安置回原处,底壁插入土中约10 cm,底座内种植作物。底座顶端有深、宽均为3 cm的密封水槽,采样前往槽内注水以防底座和顶箱结合处漏气。顶箱（50 cm×50 cm×50 cm）外覆绝热材料以减少采样箱内温度随外界气温升高对试验结果的影响,同时,顶箱内部安装2个小风扇,用于混合箱内气体。顶箱侧面安装电源插头、温度探头（JM624型便携式测温计）和采样管。试验期间,采样频率为每周1次,每次控制在当天9：00—11：00间进行,采样时用60 mL注射器采集第1次样品,之后每间隔10 min 采样1 次,罩箱时间为30 min,共采集4 个气体样品。在气体样品采集的同时,记下开始和结束时的气温和5 cm 深土壤温度,并采集表层土样测定土壤含水量、铵态氮及硝态氮含量,于每个月采集土样测定土壤碱解氮含量,待作物收获后采集表层土壤测定土壤总氮含量。遇到下雨及施肥情况,采样频率增加,为每2 d一次,持续一周。1.4 数据处理
采用气相色谱（Agilent 7890A气相色谱仪）测定温室气体CH4、CO2、N2O浓度。高纯氮气（N2）与氩甲烷（ArCH4）分别作为CH4和N2O的载气。N2O检测器为ECD（电子俘获检测器）,检测温度300℃;CO2和CH4检测器为FID（火焰离子化检测器）,检测温度为300℃,柱温50℃,气体排放速率由4个气样浓度值经线性回归分析得出具体工作条件详见文献[16]。温室气体排放量（f）的计算公式[10]为：
式中,f表示CO2排放量（mg·m-2·h-1）、N2O和CH4排放量（μg·m-2·h-1）;ρ表示标准状态下CO2-C、CH4-C和N2O-N的密度;V为采样箱体积（m3）;A为采样底座内土壤表面积（m2）;ΔC/Δt表示气体的排放速率,即通过每个小区每次采集的4个样品的气体浓度与时间进行一次线性回归,回归方程的系数就是ΔC/Δt;T为采样箱内温度（℃）。
各处理每次排放量用各重复平均值表示;作物季节平均排放通量则以每次采样时间间隔为权重进行加权平均求得;生长季累积排放量以每次排放量的加权和表示。
全球增温潜势（Global Warming Potential,GWP）：表示不同温室气体排放的综合指标,一般以CO2为标准,用CO2当量表示。计算公式为[25]：
式中,GWP为作物生长季温室气体排放的综合温室效应（kg CO2-e·hm-2）,R(CH4)和R(N2O)分别为作物生长季CH4和N2O的排放总量（kg·hm-2）。
土壤基本理化性质测定：土壤碱解氮采用碱解扩散法测定;土壤速效钾采用pH 7,1 mol·L-1醋酸铵浸提-火焰光度计法;土壤速效磷采用pH 8.5,0.5 mol·L-1NaHCO3浸提-钼蓝比色法测定;土壤有机质采用重铬酸钾容量法测定;土壤总氮采用H2SO4-H2O2消煮,蒸馏滴定测定;土壤铵态氮和硝态氮采用2 mol·L-1 KCl提取,取滤液分别用靛酚蓝比色法和紫外分光光度计法测定;土样具体测定详细步骤参见文献[26]。
采用SPSS20.0、Origin 8.5和Excel 2010软件进行数据处理、绘图制表。所有的结果均用 3 次测定结果的平均值表示。不同处理之间的多重比较采用LSD 最小显著差数法（P<0.05）,采用重复测定方差分析方法比较不同蔬菜季、试验处理及其交互作用对温室气体累积排放量的影响（P<0.05）。
2 结果
2.1 有机物料等氮量施用对土壤氮形态的影响
2.1.1 铵态氮 如图1-A所示,在每次施肥和追肥一周内,各处理（除CK外）的土壤铵态氮含量均出现峰值,随后呈下降趋势,可见施肥在短期内可以有效提高土壤铵态氮含量。莴笋季,施基肥一周内（2016年10月30）,MF处理的铵态氮含量出现了最高值（96.20 mg·kg-1）,相较于F处理的最高值增加了34.4%;在追肥后（2016年12月9日）,BF处理的铵态氮含量达到最高值,为160.74 mg·kg-1。卷心菜季,第一追肥后（2017年2月21日）,MF、BF和CF处理的铵态氮含量在一周内出现峰值后呈下降趋势,而F和SF处理的铵态氮含量均超过了95 mg·kg-1;在第二次追肥后（3月27日）,F处理的铵态氮含量达到最高值（114.44 mg·kg-1）,而各有机物料处理的铵态氮含量均低于78 mg·kg-1。辣椒季,CF处理的铵态氮含量低于其他处理（除CK外）,而F处理的土壤铵态氮含量普遍较高（72.35—161.39 mg·kg-1）。图1
新窗口打开|下载原图ZIP|生成PPT图1不同处理下的土壤氮形态变化
图中不同的小写字母表示处理间达到显著差异（P<0.05）,不同大写字母表示季节间达到显著差异（P<0.01）
Fig. 1Changes of soil nitrogen formation under different treatments
The different small letters indicate significant differences between treatments at P<0.05. The different capital letters indicate significant differences between planting at P<0.01
2.1.2 硝态氮 试验期内,土壤硝态氮含量的动态变化类似于铵态氮,主要表现为在施肥和追肥后,各处理（除CK外）的硝态氮含量出现了峰值。如图1-B所示,莴笋季,基肥施用后,各试验处理的硝态氮含量相比铵态氮而言峰值推迟,CF处理的硝态氮在基肥施用一周内的含量变化（8.91—28.85 mg·kg-1）高于其他处理。卷心菜季,各试验处理的硝态氮含量的峰值仍约处在基肥施用一个月后（2017年2月15日）,其中CF处理土壤硝态氮含量最高,较F处理提高了41.9%。辣椒季,各试验处理的硝态氮含量出现了两次明显的峰值,第一次峰值为基肥施用一周后,其中BF处理在出现了辣椒生育期的硝态氮含量的最高值（147.92 mg·kg-1）,比同期的F处理增加了30.0%;第二次峰值为追肥一个月后（2017年7月26日）,其中MF处理的硝态氮含量最高（148.82 mg·kg-1）,而CF处理最低（78.66 mg·kg-1）。
2.1.3 碱解氮 如图1-C所示,与CK相比,各试验处理的土壤碱解氮含量均增高,可见施肥可以增加土壤碱解氮的含量。莴笋季和辣椒季,F处理的土壤碱解氮含量普遍高于有机物料还田处理,最高可达152.31 mg·kg-1。卷心菜季,CF处理的碱解氮含量的最高值,较同期F处理增加了91.6%,其次为MF处理（增加56.5%）。总体上,试验期内,F处理的碱解氮含量的平均值最高（115.98 mg·kg-1）,其次为CF处理,而BF处理的碱解氮含量的平均值较低（99.28 mg·kg-1）。
2.1.4 总氮 从图1-D可以看出,同一处理下,不同作物生育期内土壤总氮含量存在差异,其中对照CK、CF处理的三季作物间的土壤总氮含量差异不显著（P>0.05）,而SF和MF处理的总氮含量随着试验时间的增加呈下降趋势,且辣椒季的土壤总氮明显低于前两季作物。在同一作物生物期内,除辣椒季的SF处理外,各有机物料处理的土壤总氮含量均高于对照CK和F处理;其中莴笋季的MF处理较F处理明显提高了14.0%,卷心菜季的有机物料处理的土壤总氮含量比F处理显著增加了0.15—0.40 g·kg-1,随着种植时间的增加,辣椒季,仅BF处理较F处理显著增加了0.17 g·kg-1（P<0.05）。
2.2 有机物料等氮量施用对N2O,CO2及CH4排放量的影响
2.2.1 N2O 排放量 如图2-A所示,各处理的N2O 排放高峰主要集中在4—7月,且每次化肥施用后均会提高N2O排放量。与对照CK相比,常规化肥施用和有机物配施化肥处理均提高了N2O排放量,其中CF处理的N2O排放量明显高于其他处理,其次为MF和SF处理,尤其是在牛粪刚施入的一周内（2016年11月3 日和2017年5月15日）出现排放高峰,分别为1 239.8和3 933.6 μg·m-2·h-1。与F处理相比,SF、MF和CF均提高了N2O排放量,而BF处理能降低N2O排放量,试验期内平均降低了7.5%。图2
新窗口打开|下载原图ZIP|生成PPT图2不同处理下的N2O,CO2及CH4排放量变化
Fig. 2Emission fluxes of N2O, CO2 and CH4 under different treatments
2.2.2 CO2排放量 如图2-B所示,卷心菜季（2017年1—5月）和辣椒季（2017年5—9月）的CO2排放量高于莴笋季（2016年10月—2017年1月）,试验期内,CO2排放出现了两次峰值,分别出现在2017年3—4月和8月。莴笋季前期即第一次有机物料施用后,MF处理的CO2排放量明显高于其他处理,最高可达1 219.5 mg·m-2·h-1,其次为CF处理。F、SF、MF和CF处理在2017年3月28日前后出现了CO2第一次排放峰值,BF处理则推迟了CO2第一次排放峰值（2017年4月13日）。试验期内,MF处理的CO2平均排放量最大（962.9 mg·m-2·h-1）,其次为CF,BF和SF,分别较F处理提高了39.3%、28.9%、25.3%和16.5%。
2.2.3 CH4排放量 与N2O和CO2排放量相比,各处理的CH4排放量波动并不明显。如图2-C所示,在有机物料第一还田后（2016年10月）,CH4排放量呈增加趋势,其中BF和CF处理的CH4排放量较高。在第二次有机物料还田后（2017年5月）,仅CF处理出现了CH4排放峰（146.7—186.7 μg·m-2·h-1）,而BF则出现了CH4排放负值（-109.8—-19.4 μg·m-2·h-1）。随着种植时间的增加,辣椒季后期各处理的CH4排放量波动较大,其中BF处理于2017年8月30日均达到排放峰值（668.7 μg·m-2·h-1）,而其他有机物料处理均为排放负值;SF和MF处理于同月9日出现CH4排放最低值,分别为-312.4和-455.5 μg·m-2·h-1。
2.3 有机物料等氮量施用对N2O,CO2,CH4累积排放量及增温潜势的影响
2.3.1 累积排放量 通过计算3种温室气体的累积排放量发现（图3）,辣椒季温室气体累积排放量明显高于卷心菜和莴笋季（P<0.01）。试验期内（图3-A）,各试验处理较对照CK均提高了N2O累积排放量,与F处理相比,CF、MF和SF处理的N2O累积排放量均显著提高了92.7%—202.8%,而BF明显降低了莴笋季的N2O累积排放量（P<0.05）。对CO2累积排放量而言（图3-B）,有机物料的添加增加了其排放量,尤其是辣椒季的CO2累积排放量明显高于F处理;而SF和MF处理较F处理明显降低了卷心菜季的CO2累积排放量;除BF处理较F处理降低667.4 kg·hm-2外,其他3种有机物料处理均显著提高了莴笋季的CO2累积排放量（P<0.05）。如图3-C所示,CF处理的莴笋季和卷心菜季的CH4累积排放量最高,分别为0.2和0.9 kg·hm-2;各有机物料处理均降低了辣椒季CH4累积排放量,除SF和MF处理的CH4累积排放量为负值外,BF和CF处理较F处理显著降低了72.1%和44.9%（P<0.05）。通过重复测定方差分析发现,不同蔬菜季、试验处理对N2O（F=152.088,P=0.000<0.05）,CO2（F=64.648,P=0.000<0.05）,CH4（F=151.072,P=0.000<0.05）累积排放量存在显著的交互效应。图3
新窗口打开|下载原图ZIP|生成PPT图3不同处理下的N2O,CO2及CH4累积排放通变化
图中不同的小写字母表示处理间达到显著差异（P<0.05）,不同大写字母表示季节间达到显著差异（P<0.01）
Fig. 3Cumulative emission of N2O, CO2 and CH4 under different treatments
The different small letters indicate significant differences between treatments at P<0.05. The different capital letters indicate significant differences between planting at P<0.01
2.3.2 增温潜势 从表2可以看出,试验期内,各处理较CK均提高了N2O和CO2平均排放通量。CF处理较F处理显著增加了N2O平均排放通量,增量可达31.5 kg·hm-2,其次为MF和SF处理（P<0.05）,而BF处理对N2O平均排放通量的影响相对于F处理而言并不显著。有机物料处理的CO2平均排放通量,表现为MF≈BF≈CF>SF,较F处理显著增加了12.8%— 35.6%（P<0.05）。对CH4平均排放通量而言,除CF外,其他有机物料处理均显著降低了CH4平均排放通量,其中MF和SF处理均表现为负值。进一步计算增温潜势发现,各有机物料均提高了增温潜势,其中CF较F处理显著提高了42.0%,其次为MF处理。
Table 2
表2
表2不同处理下的温室气体平均排放通量和增温潜势变化
Table 2
| 处理 Treatment | 平均排放通量 Mean greenhouse gas emission flux (kg·hm-2) | GWP (kg CO2-e·hm-2) | ||
|---|---|---|---|---|
| N2O | CO2 | CH4 | ||
| CK | 3.7±0.1e | 55537±2735c | 2.0±0.21a | 56578±2704d |
| F | 15.6±0.3d | 56544±1803c | 1.7±0.28b | 60716±1901d |
| SF | 30.0±1.4c | 63761±3623b | -0.1±0.0d | 71697±3989c |
| MF | 34.7±0.9b | 76675±1720a | -1.3±0.2e | 85828±1957a |
| BF | 16.8±0.4d | 75254±867a | 0.4±0.0c | 79709±883b |
| CF | 47.1±4.0a | 73665±2603a | 2.1±0.2a | 86216±3679a |
新窗口打开|下载CSV
2.4 环境因子与温室气体排放相关性分析
图4是试验期内,各处理的土温、气温以及土壤含水量变化。各处理的辣椒季温度（包括5 cm土温和气温）明显高于莴笋季和卷心菜季,且辣椒季的土壤含水量波动较大。通过相关性分析发现（表3）：N2O排放量与温度（包括5 cm土温和气温）存在显著的相关关系（P<0.05）;CO2排放量与与温度（包括5 cm土温和气温）存在极显著的正相关,而与土壤含水量呈极显著的负相关（P<0.01）;CH4排放量与土壤含水量呈显著正相关（P<0.05）,而与温度的相关性不大。图4
新窗口打开|下载原图ZIP|生成PPT图4各处理5 cm土层温度、气温及含水量变化
Fig. 4Variation characteristics of 5 cm soil temperature, air temperature and soil moisture content under different treatments
Table 3
表3
表3温室气体排放与温度、含水量相关分析
Table 3
| N2O排放量 N2O emission flux | CO2排放量 CO2 emission flux | CH4排放量 CH4 emission flux | 5 cm土温 5 cm soil temperature | 气温 Air temperature | 土壤含水量 Soil moisture content | |
|---|---|---|---|---|---|---|
| N2O排放量 N2O emission flux | 1 | 0.207** | 0.148** | 0.127* | 0.121* | 0.074 |
| CO2排放量 CO2 emission flux | 1 | 0.020 | 0.563** | 0.609** | -0.357** | |
| CH4排放量 CH4 emission flux | 1 | .075 | 0.066 | 0.111* | ||
| 5 cm土温 5 cm soil temperature | 1 | 0.975** | -0.637** | |||
| 气温 Air temperature | 1 | -0.629** | ||||
| 土壤含水量 Soil moisture content | 1 |
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3 讨论
3.1 施肥与土壤氮形态
本研究表明,施肥灌水后,各处理土壤铵态氮和硝态氮含量均出现峰值,随后呈下降趋势,这是由于氮肥的施用促进了作物通过根系归还土壤有机物数量,从而增加了微生物活性和根系分泌,促进了有机质的矿化,增加土壤矿质氮的含量[27],因此施肥在短期内可以有效提高土壤铵态氮和硝态氮的含量,为硝化和反硝化作用提供了底物,促进N2O排放（图2-A）。同时土壤中的铵态氮和硝态氮存在“此消彼长”关系,一般温度较高,含水量较少的条件下,硝化作用比较强烈,铵态氮含量比较少,以硝态氮为主[28],这与段鹏鹏等[12]研究结果一致。但是不同种植季度、不同处理对土壤氮形态含量的影响存在差异。这主要是因为不同种植季度的温度、水分含量存在差异,同时不同作物的生育期不同,最终导致土壤氮形态分布存在差异。HOPKINS和SHIEL[29]研究表明单施化肥对微生物有直接的毒害作用,从而减少了对土壤可溶性氮的吸收,因此本研究中F处理的土壤铵态氮、硝态氮及碱解氮含量并不低于甚至高于其他物料处理。相对于秸秆类有机物料,牛粪等有机肥还田后能较快地提高土壤微生物量和碳、氮的有效性,增强微生物活性,促进土壤养分的转化和释放[11],故在温度低,含水量变化不大的莴笋季和卷心菜季下,因硝化和反硝化作用的强度不大,故因二者作用消耗的氮底物也较少,从而导致CF处理的硝态氮和碱解氮含量均都高于其他物料处理。辣椒季,于6月19日追肥后,常规施肥处理较有机物料处理的微生物活性低,故造成碱解氮盈余,同时高温多雨的环境,频繁的干湿交替使得土壤厌氧和氧化环境也频繁交替,但由于生物质炭能改善土壤的通气状况,增加阳离子交换量,同时较高C/N比促使土壤中氮的固定,减少氮素流失,提高氮素的供应能力[11,30],因此BF处理的辣椒季的碱解氮含量高于其他物料处理。3.2 施肥与N2O,CO2及CH4排放
农业对温室气体（N2O、CO2、CH4）的排放具有重要的作用,其中旱地农田是N2O和CO2的重要排放源[31]。施肥是影响N2O排放的主要因素,肥料的类型对农田N2O排放的影响仍存在争议[32,33]。本研究中,牛粪、菌渣、秸秆有机物料与化肥配施处理的农田N2O平均排放量为362.8—630.1 μg·m-2·h-1,超过对照CK（44.0 μg·m-2·h-1）和常规化肥施用处理（F,189.0 μg·m-2·h-1）,尤其牛粪与化肥配施（CF,630.1 μg·m-2·h-1）处理,而生物质炭配施化肥（BF,174.8 μg·m-2·h-1）处理降低了N2O排放量。这是因为有机物料的施用提高了土壤碳素含量,为微生物参与下的N2O排放的硝化和反硝化过程提供充足的营养元素[21,34-35],因此相较于对照CK和常规施肥处理而言,有机物料与化肥配施处理提高了N2O排放;与秸秆、菌渣有机物料相比,牛粪的C/N较低（C/N=20.2）,还田后会刺激土壤中氮分解,增加N2O排放,因此牛粪与化肥配施处理的N2O排放量最大。但是由于生物质炭一方面具有吸附性,在土壤中添加生物质炭可以提高阳离子交换量,增加了土壤对NH4+的吸附,减少了参与硝化过程的NH4+浓度,从而减少了N2O的排放[30];另一方面生物质炭C/N较高,加之生物质炭能改善土壤的通气性,进而限制硝化作用及不利于在厌氧条件下氮素微生物的反硝化作用,加速氮素固定,从而减少N2O排放[36]。此外本试验中生物质炭增加了土壤硝态氮含量而减少了N2O排放量,可能是因为生物质炭的类型、施用量、土壤均会影响生物质炭的效果,因此生物质炭还田后会改变土壤性质以及硝化微生物活性,有利于形成硝化作用的最终产物（硝态氮）,不利于形成中间产物（N2O）,从而降低了土壤硝化作用中N2O产生比例[16]。在莴笋和卷心菜种植季,无论是常规化肥还是有机物料与化肥配施处理较对照CK均提高了CO2的排放;但是随着种植时间的进行,部分施用化肥处理的CO2排放量低于CK,早期研究认为长时间施用化肥（尤其氮肥）可以减弱土壤呼吸,从而促进了土壤中碳的贮存[37,38],但目前具体机理有待进一步研究。试验期内,MF处理的CO2平均排放量最大（962.9 mg·m-2·h- 1）,尤其是菌渣还田后的前期,与栗方亮等[39]研究结果类似。这是因为分解前期菌渣中可溶性有机物较多,同时菌渣中富含蛋白质,中微量元素以及灰分、粗脂肪、粗纤维等,其还田后为微生物提供了营养物质和能源物质,从而促进了土壤呼吸[39],增加了CO2排放。因此本试验中,菌渣还田的前期CO2排放量较大。但随着种植时间的延长,易分解组分被微生物分解利用殆尽,开始转向利用较难分解组分,有机碳分解量下降,从而导致CO2排放量减少[38]。夏季（7—9月）高温多雨使得土壤环境变化频繁,而生物质炭由于自身疏松多孔特点和吸附性能,能改善土壤的通气性、提高土壤的保水性和保持土壤养分,因此在变化频繁的土壤环境下,生物质炭与化肥配施处理较其他处理为微生物提供了较好的土壤环境,提高了土壤微生物量和酶活性[40,41],同时生物质炭的“正激发效应”即生物质炭中不稳定性碳组分的微生物的降解作用会促进土壤表观呼吸速率[42,43],因此在整个试验的夏季（7—9月）,BF处理的CO2排放量高于其他处理。此外,施肥灌水亦能增加各试验处理的CO2排放量,均出现了的CO2排放峰,这是因为施肥灌水一方面为土壤微生物提供营养物质,加速土壤微生物呼吸释放CO2;另一方面追施氮肥（尿素）,通过改变C/N,加速土壤有机物矿化,从而增加CO2排放[39]。
旱地土壤通透性较好,不易产生厌氧环境,在旱地土壤中CH4排放量较低,因此认为旱地是大气中CH4重要的吸收汇[44]。本研究中,在等养分量条件下,各处理的CH4排放的特点多表现为大气中CH4汇,这与韩园园等[45]研究结果类似。其中在第一次物料还田后,外源有机物料的增加,较对照CK和F处理为微生物提供了营养物质和能源物质,因此各有机物料添加前期的CH4排放量均呈增加趋势。牛粪的C/N比较低,还田后可以促进氮素的矿化生成铵态氮和硝态氮,但是由于铵态氮的分子结构类似于甲烷,同样会被甲烷单氧化酶氧化,从而铵态氮的存在会抑制土壤对CH4的吸收[46,47],因此试验期内,牛粪与化肥处理CH4平均排放量最大（39.1 μg·m-2·h-1）。张凯莉等[44]研究表明温度过低时,会抑制产甲烷菌和甲烷氧化菌的活动,因此本研究莴笋季和卷心菜季的温度较低,与CH4有关的微生物活性不高,使得该种植时期的土壤CH4排放量波动不明显;而辣椒季土壤CH4排放量波动大,并出现了排放峰值,且各处理的CH4排放量差别较大,尤其是8月BF处理达到排放峰,而其他有机物料处理多为排放负值,其中秸秆、菌渣与化肥配施处理的CH4排放量最低。这是因为8月高温多雨使得土壤干湿交替频繁,土壤的厌氧和氧化环境也交替频繁,从而导致甲烷氧化菌和产甲烷菌活性变化,最终使得辣椒季的土壤CH4排放量波动大。但是由于生物质炭的吸水性强,短期内较其他处理更能涵养水分,为产甲烷菌提供厌氧环境,促进了CH4排放,而且通过相关性分析（表3）：CH4排放量与土壤的含水量呈显著的相关关系,同时辣椒季的温度多为30℃以上,为产甲烷菌的适合温度（30—40℃）[44],因此在高温多水的短期内,生物质炭与化肥配施会促进CH4排放。
3.3 施肥与N2O,CO2及CH4累积排放量和增温潜势
水热条件是影响温室气体排放重要环境因子,有研究表明硝化作用的最适土壤温度为15—35℃,反硝化作用的最适土壤温度为5—75℃,土壤表层温度与土壤N2O排放速率存在显著的相关关系[48,49]。在本研究中,辣椒季的N2O累积排放量明显高于莴笋季和卷心菜季,通过相关性分析发现（表3）：N2O排放量与温度（包括5 cm土温和气温）存在显著的相关关系;这可能是由于辣椒生育期集中在夏季,高温多雨的环境,土壤中含水量较高,土壤通气性变差,有利于反硝化过程的发生,最终促进了N2O排放[17]。肥料（尤其氮肥）的施用会增加硝化和反硝化作用的底物,提高N2O的产生和排放,故各试验处理的N2O平均排放通量均显著高于对照CK;此外有机物料的添加能提高土壤的碳素含量,为微生物提供营养物质,提高了微生物活性[21,34],因此与F处理相比,其他物料处理的N2O平均排放通量均提高。而BF处理的N2O平均排放通量的增加量较少,这是由于生物质炭的自身特点会吸附NH4+,同时改善土壤的通气状况,最终减少了N2O的产生和排放。较低C/N的牛粪还田后,会刺激土壤中氮分解,增加N2O排放,因此CF处理的N2O平均排放通量最大。温度和土壤水分共同决定了土壤CO2排放的季节特征,尤其是5 cm土层温度能够解释土壤呼吸变化的82%—94%,但水分对土壤CO2排放的影响具有复杂性与不确定性[50,51,52]。通过相关分析发现,本试验中的CO2排放量与温度存在极显著的正相关关系,而与土壤含水量呈极显著的负相关关系。由于辣椒季生育期的表层土温较高,且生育期长于莴笋季和卷心菜季,从而导致辣椒季的CO2累积排放量明显高于其他两季作物。物料的添加,为土壤带入碳源,故有机物料的添加均显著增加了试验期内CO2平均排放通量;与其他物料相比,秸秆有机碳含量较低,还田后可供微生物利用的碳源较少,因此SF处理的CO2平均排放通量低于其他物料处理。旱地的含水量相较于水田少,在整个试验观测期内,CH4排放与土壤含水量存在显著的正相关关系（表3）,因此含水量成为CH4排放的重要决定因素。辣椒季高温多雨导致了该种植季的土壤环境变化频繁,故辣椒季,各处理的CH4 “源”或“汇”特征较含水量变化不大的莴笋和卷心菜季的明显。与对照CK和常规施肥处理相比,CF处理增加了CH4平均排放通量,而其他物料与化肥配施均显著降低CH4平均排放通量,促进了CH4累积吸收量。这可能是牛粪的C/N比较低,还田后可以促进有机氮矿化生成铵态氮和硝态氮,但是铵态氮的存在会抑制土壤对CH4的吸收[46,47],因此牛粪与化肥处理增加了CH4平均排放通量。由于N2O,CO2,CH4的增温潜势不同,为定量分析不同温室气体对全球变暖的相对影响,本研究采用IPCC确定的因素来评价100年尺度上不同处理的温室气体的综合增温效应（GWP）[53]。本研究中,物料处理的GWP均显著高于对照CK和常规化肥处理,这与李露等[54]研究结果类似,这可能是因为本试验条件下,N2O对GWP的贡献率高于CH4,同时物料处理的CO2平均排放通量高于CK和F处理,所以各物料处理均提高了综合增温效益。但是4种物料相比,SF和BF处理的GWP相对较低,这是因为虽然BF处理增加了CO2平均排放通量,但是明显降低了N2O和CH4平均排放通量,而SF处理主要表现在降低CO2和CH4平均排放通量,可见不同物料处理对3种温室气体的减排效果存在差异。
4 结论
牛粪配施化肥提高了莴笋和卷心菜季的铵态氮含量,生物质炭配施化肥则提高了辣椒季硝态氮和碱解氮含量。N2O、CO2、CH4排放高峰主要集中在夏季,且施肥灌水后会出现排放峰。与常规施肥相比,生物质炭配施化肥降低了N2O排放,牛粪配施化肥显著增加了N2O排放,但各处理均促进了CO2排放,生物质炭则推迟了CO2排放峰。秸秆、菌渣配施化肥减少了CH4排放,牛粪则显著增加了CH4平均排放通量。有机物料配施化肥提高了温室气体的综合增温效应,秸秆、生物质炭处理的增温潜势低于菌渣、牛粪处理。总体上,等养分投入下,有机物料配施化肥对蔬菜连作模式下的紫色土氮形态分布和温室气体的影响各异,与水热条件密切相关;生物质炭、秸秆与化肥配施处理能增加有效氮含量,减少温室气体的排放,缓解温室效应;而牛粪与化肥配施会增加温室气体排放。
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DOI:10.3864/j.issn.0578-1752.2014.02.011URLMagsci [本文引用: 1]
【目的】稻田生态系统的温室气体排放一直是气候变化领域的研究热点，对发展低碳农业和缓解全球变暖具有重要意义。研究控释肥和添加剂对双季稻（Oryza sative L）温室气体排放和产量的影响，旨在综合评价其减排效果，筛选既能保证产量又能有效减排的施肥措施。【方法】以华中江汉平原地区双季稻为研究对象，设置6种不同控释肥或添加剂处理，包括①习惯施肥作为对照，②硫包膜控释尿素，③树脂包膜控释尿素，④缓释碧晶尿素，⑤尿素中加入质量分数1%的硝化抑制剂二甲基吡唑磷酸盐（DMPP），⑥施肥时泼洒与尿素等量的1：200倍稀释有效微生物菌剂培养液（EM菌剂），采用自动静态箱-气相色谱法对温室气体排放通量进行长期连续监测，同步观测土壤无机氮素和产量，得出不同施肥处理的温室气体（CH4和N2O）排放特征，由内插加权法求得排放总量，最终计算出综合温室效应和排放强度。【结果】不同施肥处理下CH4和N2O排放通量具有较为明显的季节变化规律。早稻CH4排放总量以树脂包膜控释尿素最低，晚稻以碧晶尿素最低；而早稻和晚稻N2O排放总量均以硝化抑制剂DMPP最低。综合两个季节，各施肥处理的综合温室效应（以CO2当量100年算）差异显著（P＜0.05），其中常规施肥＞硫包膜控释尿素＞硝化抑制剂DMPP＞EM菌剂＞碧晶尿素＞树脂包膜控释尿素；控释肥和添加剂处理对比常规均有不同程度的减排效果，其中树脂包膜控释尿素减排效果最高为56.2%，碧晶尿素次之为45.6%，且晚稻减排效果明显高于早稻。早稻控释肥和添加剂处理产量与常规施肥差异不显著，晚稻则存在显著增产，增产幅度为13.5%—16.2%。各处理的温室气体排放强度GHGI以树脂包膜控释尿素最低，与常规施肥差异极显著（P＜0.01）。【结论】双季稻不同施肥处理CH4和N2O的排放总量差异显著，控释肥和添加剂处理均能达到不同程度的减排。控释肥和添加剂处理对早稻增产效果差异不显著，对晚稻增产效果差异显著，减排效果也高于早稻。综合考虑经济效益和减排效果，可得出在当前的稻田管理条件下施用包膜控释肥、抑制剂和生物菌剂，能保证产量并有效降低温室气体排放，是水稻低碳高产可行的施肥措施。
DOI:10.3864/j.issn.0578-1752.2014.02.011URLMagsci [本文引用: 1]
【目的】稻田生态系统的温室气体排放一直是气候变化领域的研究热点，对发展低碳农业和缓解全球变暖具有重要意义。研究控释肥和添加剂对双季稻（Oryza sative L）温室气体排放和产量的影响，旨在综合评价其减排效果，筛选既能保证产量又能有效减排的施肥措施。【方法】以华中江汉平原地区双季稻为研究对象，设置6种不同控释肥或添加剂处理，包括①习惯施肥作为对照，②硫包膜控释尿素，③树脂包膜控释尿素，④缓释碧晶尿素，⑤尿素中加入质量分数1%的硝化抑制剂二甲基吡唑磷酸盐（DMPP），⑥施肥时泼洒与尿素等量的1：200倍稀释有效微生物菌剂培养液（EM菌剂），采用自动静态箱-气相色谱法对温室气体排放通量进行长期连续监测，同步观测土壤无机氮素和产量，得出不同施肥处理的温室气体（CH4和N2O）排放特征，由内插加权法求得排放总量，最终计算出综合温室效应和排放强度。【结果】不同施肥处理下CH4和N2O排放通量具有较为明显的季节变化规律。早稻CH4排放总量以树脂包膜控释尿素最低，晚稻以碧晶尿素最低；而早稻和晚稻N2O排放总量均以硝化抑制剂DMPP最低。综合两个季节，各施肥处理的综合温室效应（以CO2当量100年算）差异显著（P＜0.05），其中常规施肥＞硫包膜控释尿素＞硝化抑制剂DMPP＞EM菌剂＞碧晶尿素＞树脂包膜控释尿素；控释肥和添加剂处理对比常规均有不同程度的减排效果，其中树脂包膜控释尿素减排效果最高为56.2%，碧晶尿素次之为45.6%，且晚稻减排效果明显高于早稻。早稻控释肥和添加剂处理产量与常规施肥差异不显著，晚稻则存在显著增产，增产幅度为13.5%—16.2%。各处理的温室气体排放强度GHGI以树脂包膜控释尿素最低，与常规施肥差异极显著（P＜0.01）。【结论】双季稻不同施肥处理CH4和N2O的排放总量差异显著，控释肥和添加剂处理均能达到不同程度的减排。控释肥和添加剂处理对早稻增产效果差异不显著，对晚稻增产效果差异显著，减排效果也高于早稻。综合考虑经济效益和减排效果，可得出在当前的稻田管理条件下施用包膜控释肥、抑制剂和生物菌剂，能保证产量并有效降低温室气体排放，是水稻低碳高产可行的施肥措施。
URL [本文引用: 1]
[1] The authors collect 54 direct N2O emission factors (EFds) obtained from 12 sites of Chinese croplands, of which 60% are underestimated by 29% and 30% are overestimated by 50% due to observation shortages. The biases of EFds are corrected and their uncertainties are re-estimated. Of the 31 site-scale EFds, 42% are lower by 58% and 26% are higher by 143% than the Intergovernmental Panel on Climate Change default. Periodically wetting/drying the fields or doubling nitrogen fertilizers may double or even triple an EFd. The direct N2O emission from Chinese croplands is estimated at 275 0103 109 g N2O-N yr0908081 in the 1990s, of which 09080420% is due to vegetable cultivation. The great uncertainty of this estimate, 09080879% to 135%, is overwhelmingly due to the huge uncertainty in estimating EFds (09080878 00± 15% to 129 00± 62%). Direct N2O emission intensities significantly depend upon the economic situation of the region, implicating a larger potential emission in the future.
[本文引用: 1]
DOI:10.1073/pnas.1700292114URLPMID:29666318 [本文引用: 1]
China’s croplands have experienced drastic changes in management practices, such as fertilization, tillage, and residue treatments, since the 1980s. There is an ongoing debate about the impact of these changes on soil organic carbon (SOC) and its implications. Here we report results from an extensive study that provided direct evidence of cropland SOC sequestration in China. Based on the soil sampling locations recorded by the Second National Soil Survey of China in 1980, we collected 4,060 soil samples in 2011 from 58 counties that represent the typical cropping systems across China. Our results showed that across the country, the average SOC stock in the topsoil (0–20 cm) increased from 28.6 Mg C ha611 in 1980 to 32.9 Mg C ha611 in 2011, representing a net increase of 140 kg C ha611 year611. However, the SOC change differed among the major agricultural regions: SOC increased in all major agronomic regions except in Northeast China. The SOC sequestration was largely attributed to increased organic inputs driven by economics and policy: while higher root biomass resulting from enhanced crop productivity by chemical fertilizers predominated before 2000, higher residue inputs following the large-scale implementation of crop straw/stover return policy took over thereafter. The SOC change was negatively related to N inputs in East China, suggesting that the excessive N inputs, plus the shallowness of plow layers, may constrain the future C sequestration in Chinese croplands. Our results indicate that cropland SOC sequestration can be achieved through effectively manipulating economic and policy incentives to farmers.
DOI:10.1016/j.atmosenv.2011.09.045URL [本文引用: 1]
The estimation of nitrous oxide (NO) emissions based on specific cropping systems is important for accurate national NO budgets. Intensively managed vegetable cultivation is responsible for large NO emissions in mainland China. However, little information can be obtained on the nationwide estimation of direct NO emissions from vegetable fields. Estimates of fertilizer-induced direct NO emissions from vegetable fields in mainland China were thus obtained by compiling and analyzing reported data in peer-reviewed journals and research reports. The results indicated that the seasonal NO emissions from vegetable fields significantly increased with nitrogen (N) fertilizer application ( O were estimated to be 0.55 ± 0.05% and 1.067 ± 0.277 kg N ha yr, respectively. The EF was reduced and the background emission of NO increased when the measurement duration was prolonged from ≤100 d to >100 and ≤200 d. Comparable results were obtained by the maximum likelihood (ML) model, with an EF of 0.49 ± 0.06% and background NO emissions of 1.228 ± 0.189 kg N ha yr. Based on the OLS-derived parameters, the fertilizer-induced direct emissions and background emissions of NO were estimated to be 66.95 Gg N and 19.63 Gg N, respectively, in 2009, and the annual NO emissions were much higher in the provinces of Shandong, Henan, Hebei and Sichuan. The estimated NO emissions from vegetable fields accounted for 21.4% of the total direct NO emissions from Chinese croplands, with large uncertainties. Therefore, the EF and background emissions of NO for each cropping system, particularly for intensively managed vegetable fields, should be specifically determined for accurate national NO inventories.Highlights? Estimation of EF and background emission of NO from Chinese vegetable fields. ? Comparable estimates of EF and background emission obtained by maximum likelihood- and ordinary least squares-models. ? Estimation of provincial distribution of direct NO emission from vegetable fields.
DOI:10.1016/j.soilbio.2010.09.011URL [本文引用: 1]
Plants are capable of taking up nitrogen (N) in both organic and inorganic forms, so the concentrations and relative proportions of different N forms in soils are likely to be important determinants of their N nutrition. Therefore, there is a need for greater knowledge of the N profiles of soils. In the study presented here we examined the potential plant-available N in soils from four sites with various agricultural histories (one recently fertilized), using small tension lysimeters to collect free and bound amino acids and inorganic N forms in solution, with minimal soil disturbance and with intact plants present. Subsequent analysis showed that concentrations of free amino acids ranged from 0.1 to 12.7 M, whereas concentrations of bound amino acids were on average 50 times higher, and higher than ammonium and nitrate concentrations in all three unfertilized soils. In contrast, nitrate strongly dominated in the fertilized soil. Bound amino acids are likely to represent a potential replenishment pool for free amino acids, so the abundance and rate at which amino acid-containing substances are depolymerized might be important determinants of the availability of free amino acids. Our results highlight the need for further research on the liberation of free amino acids from polymers in agricultural soil, and the importance of bound amino acids as N sources for plants.
DOI:10.11975/j.issn.1002-6819.2016.z2.015URL [本文引用: 2]
农业有机物料的循环利用不但能解决自身对环境的污染问题、为农田提供养分，而且对增加土壤碳库、减少温室气体（GHG）排放和应对气候变化也发挥着重要作用。该文选用来自5个涉农系统的有机物料（秸秆、沼渣、菌渣、酒渣和猪粪）进行还田，以单施化肥为对照，基于田间定位试验，研究不同有机物料还田对农田土壤碳库、土壤温室气体排放的影响，在此基础上采用土壤碳库法对农田系统净温室气体排放（NGHGE）进行综合评价。2013-2015年的结果表明：1）与无机肥对照相比，有机物料还田均不同程度地提高农田土壤固碳能力，2013-2015年平均提高0-20cm土壤碳储量63.52%，其中秸秆、沼渣、菌渣、酒渣和猪粪分别比无机肥提高33.13%、86.34%、75.97%、52.66%和69.48%，来自农田系统外的几种有机物料还田效果优于秸秆，更有利于土壤碳储量的增加。2）除秸秆外，有机物料还田均不同程度地增加土壤温室气体排放，与无机肥对照相比，土壤增温潜势（GWPsoil）平均增幅达到67.23%，其中，沼渣、菌渣、酒渣和猪粪处理的土壤GWPsoil分别比秸秆还田处理高30.23%、27.84%、62.10%和52.55%，秸秆还田低于酒渣和猪粪处理（P<0.05）。3）各处理的 NGHGE 均为正值，代表各处理均为温室气体的源，但是，除了菌渣还田处理的 NGHGE高于无机肥之外，其他有机物料还田的NGHGE显著低于无机肥处理（P <0.05），秸秆、沼渣、酒渣和猪粪的NGHGE分别比无机肥低52.78%、56.30%、54.19%和90.35%，说明猪粪、沼渣和酒渣经过农田系统外循环后还田之后减少温室效应效果优于直接还田的秸秆。综合显示，农业有机物料的循环利用有利于土壤碳储量的增加，除了菌渣之外，猪粪、沼渣、酒渣和秸秆还田虽均增加了土壤温室气体排放，综合土壤固碳和排放，整个农田系统的净温室气体排放还是减少了。
DOI:10.11975/j.issn.1002-6819.2016.z2.015URL [本文引用: 2]
农业有机物料的循环利用不但能解决自身对环境的污染问题、为农田提供养分，而且对增加土壤碳库、减少温室气体（GHG）排放和应对气候变化也发挥着重要作用。该文选用来自5个涉农系统的有机物料（秸秆、沼渣、菌渣、酒渣和猪粪）进行还田，以单施化肥为对照，基于田间定位试验，研究不同有机物料还田对农田土壤碳库、土壤温室气体排放的影响，在此基础上采用土壤碳库法对农田系统净温室气体排放（NGHGE）进行综合评价。2013-2015年的结果表明：1）与无机肥对照相比，有机物料还田均不同程度地提高农田土壤固碳能力，2013-2015年平均提高0-20cm土壤碳储量63.52%，其中秸秆、沼渣、菌渣、酒渣和猪粪分别比无机肥提高33.13%、86.34%、75.97%、52.66%和69.48%，来自农田系统外的几种有机物料还田效果优于秸秆，更有利于土壤碳储量的增加。2）除秸秆外，有机物料还田均不同程度地增加土壤温室气体排放，与无机肥对照相比，土壤增温潜势（GWPsoil）平均增幅达到67.23%，其中，沼渣、菌渣、酒渣和猪粪处理的土壤GWPsoil分别比秸秆还田处理高30.23%、27.84%、62.10%和52.55%，秸秆还田低于酒渣和猪粪处理（P<0.05）。3）各处理的 NGHGE 均为正值，代表各处理均为温室气体的源，但是，除了菌渣还田处理的 NGHGE高于无机肥之外，其他有机物料还田的NGHGE显著低于无机肥处理（P <0.05），秸秆、沼渣、酒渣和猪粪的NGHGE分别比无机肥低52.78%、56.30%、54.19%和90.35%，说明猪粪、沼渣和酒渣经过农田系统外循环后还田之后减少温室效应效果优于直接还田的秸秆。综合显示，农业有机物料的循环利用有利于土壤碳储量的增加，除了菌渣之外，猪粪、沼渣、酒渣和秸秆还田虽均增加了土壤温室气体排放，综合土壤固碳和排放，整个农田系统的净温室气体排放还是减少了。
URL [本文引用: 1]
URL [本文引用: 1]
DOI:10.1016/j.soilbio.2007.06.021URL [本文引用: 1]
Soil organic matter is extensively humified; some fractions existing for more than 1000 years. The soil microbial biomass is surrounded by about 50 times its mass of soil organic matter, but can only metabolize it very slowly. Paradoxically, even if more than 90% of the soil microbial biomass is killed, the mineralization of soil organic matter proceeds at the same rate as in an unperturbed soil. Here we show that soil organic matter mineralization is independent of microbial biomass size, community structure or specific activity. We suggest that the rate limiting step is governed by abiological processes (which we term the Regulatory Gate hypothesis), which convert non-bioavailable soil organic matter into bioavailable soil organic matter, and cannot be affected by the microbial population. This work challenges one of the long held theories in soil microbiology proposed by Winogradsky, of the existence of autochthonous and zymogenous microbial populations. This has significant implications for our understanding of carbon mineralization in soils and the role of soil micro-organisms in the global carbon cycle. Here we describe experiments designed to determine if the Regulatory Gate operates. We conclude that there is sufficient experimental evidence for it to be offered as a working hypothesis.
URL [本文引用: 2]
URL [本文引用: 2]
[本文引用: 3]
[本文引用: 3]
DOI:10.3864/j.issn.0578-1752.2015.23.013URL [本文引用: 2]
【目的】在氮肥与有机肥配施条件下，研究设施番茄生长期内土壤可溶性氮（矿质氮和可溶性有机氮）的动态变化，评估可溶性氮在设施土壤中的作用，为设施土壤的合理施肥提供理论参考。【方法】以连续两年不施肥（CK）、不同施氮量（N0、N1、N2、N3）、单施有机肥（M）以及不同氮量配施有机肥（MN0、MN1、MN2、MN3）的设施番茄栽培的田间小区试验的方法，研究氮肥与有机肥配施以及不同施氮量对番茄生长期、休耕期土壤可溶性氮动态变化的影响。【结果】在番茄生长期，与施用氮肥处理相比，氮肥与有机肥配施处理均能够显著增加0—30 cm土层土壤矿质氮和土壤可溶性有机氮的含量（P＜0.01），特别是提高了矿质氮的含量。土壤矿质氮和土壤可溶性有机氮均表现出比较大的动态变化，总体来说，土壤矿质氮和土壤可溶性有机氮含量均在第一穗果膨大期最高，在第二穗果膨大期土壤矿质氮含量大于可溶性有机氮含量，而在收获期土壤可溶性有机氮含量大于矿质氮含量，且在整个生长季内土壤矿质氮和土壤可溶性有机氮含量之间均有显著的正相关关系（P＜0.05）。在休耕期（番茄收获后60 d），与施用氮肥处理相比，氮肥与有机肥配施处理均能显著增加0—50 cm土层土壤矿质氮和0—10 cm土层土壤可溶性有机氮的含量（P＜0.05）；在0—50 cm土层内，土壤矿质氮和土壤可溶性有机氮的含量均随土层深度加深呈逐渐下降趋势，且在20—40 cm处有明显的累积。此外，不管是在番茄生育期还是在休耕期，总体上来看，不施有机肥处理下，土壤矿质氮和土壤可溶性有机氮的含量均以N2处理的含量为最高，而且土壤可溶性有机氮在可溶性氮中占有更大的比例；而在氮肥与有机肥配施处理中，MN2和 MN3处理的土壤矿质氮和土壤可溶性有机氮含量最高，而且在可溶性氮库中以土壤矿质氮为主。【结论】本试验条件下，适量氮肥与有机肥配施能够更好协调和改善设施土壤中可溶性氮的供应状况。
DOI:10.3864/j.issn.0578-1752.2015.23.013URL [本文引用: 2]
【目的】在氮肥与有机肥配施条件下，研究设施番茄生长期内土壤可溶性氮（矿质氮和可溶性有机氮）的动态变化，评估可溶性氮在设施土壤中的作用，为设施土壤的合理施肥提供理论参考。【方法】以连续两年不施肥（CK）、不同施氮量（N0、N1、N2、N3）、单施有机肥（M）以及不同氮量配施有机肥（MN0、MN1、MN2、MN3）的设施番茄栽培的田间小区试验的方法，研究氮肥与有机肥配施以及不同施氮量对番茄生长期、休耕期土壤可溶性氮动态变化的影响。【结果】在番茄生长期，与施用氮肥处理相比，氮肥与有机肥配施处理均能够显著增加0—30 cm土层土壤矿质氮和土壤可溶性有机氮的含量（P＜0.01），特别是提高了矿质氮的含量。土壤矿质氮和土壤可溶性有机氮均表现出比较大的动态变化，总体来说，土壤矿质氮和土壤可溶性有机氮含量均在第一穗果膨大期最高，在第二穗果膨大期土壤矿质氮含量大于可溶性有机氮含量，而在收获期土壤可溶性有机氮含量大于矿质氮含量，且在整个生长季内土壤矿质氮和土壤可溶性有机氮含量之间均有显著的正相关关系（P＜0.05）。在休耕期（番茄收获后60 d），与施用氮肥处理相比，氮肥与有机肥配施处理均能显著增加0—50 cm土层土壤矿质氮和0—10 cm土层土壤可溶性有机氮的含量（P＜0.05）；在0—50 cm土层内，土壤矿质氮和土壤可溶性有机氮的含量均随土层深度加深呈逐渐下降趋势，且在20—40 cm处有明显的累积。此外，不管是在番茄生育期还是在休耕期，总体上来看，不施有机肥处理下，土壤矿质氮和土壤可溶性有机氮的含量均以N2处理的含量为最高，而且土壤可溶性有机氮在可溶性氮中占有更大的比例；而在氮肥与有机肥配施处理中，MN2和 MN3处理的土壤矿质氮和土壤可溶性有机氮含量最高，而且在可溶性氮库中以土壤矿质氮为主。【结论】本试验条件下，适量氮肥与有机肥配施能够更好协调和改善设施土壤中可溶性氮的供应状况。
DOI:10.3878/j.issn.1006-9895.2011.04.10URL [本文引用: 1]
选取湖南典型红壤双季稻田为研究对象,采用静态箱—气相色谱法对不施肥对照(CK)、常规施化肥(NPK)、新鲜稻草与化肥配施(RS+NPK1)、菌渣与化肥配施(MR+NPK1)、新鲜牛粪与化肥配施(CD+NPK2)和沼渣与化肥配施(BD+NPK2)等6个处理的CH4和N2O排放通量进行为期一年的观测(早稻、晚稻和休闲期),研究排放特征与驱动因素。结果表明,不同处理的CH4排放均表现出"早稻生长期少,晚稻生长期多,休闲期弱"的特点,而N2O排放主要发生在水稻生长期内(78%以上),休闲期内排放较少。NPK的CH4排放比CK增加了35%,差异不显著(P0.05,P是拒绝原假设的犯错概率)。有机无机配施处理中,RS+NPK1和CD+NPK2的CH4全年累计排放量分别是MR+NPK1和BD+NPK2的2.44和2.45倍(P0.05),但后者的N2O全年累计排放量分别比前者提高了59%和102%(P0.05)。与单施化肥相比,有机无机配施使稻田氮肥N2O-N直接排放系数降低45%～80%。相关环境因素分析表明,水、热变化是驱动稻田CH4排放季节变化的主要因素。本研究未发现水分变化与N2O排放通量之间存在直接联系,而且CH4和N2O在排放时间上不存在消长关系。CH4和N2O的整体温室效应表明,CH4是当地双季稻田的主要温室气体。采用腐熟后的菌渣和沼渣代替新鲜的稻草和牛粪还田可以使稻田CH4排放量降低约60%,CH4和N2O的整体温室效应降低约50%,而稻谷产量保持不变。
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DOI:10.3878/j.issn.1006-9895.2011.04.10URL [本文引用: 1]
选取湖南典型红壤双季稻田为研究对象,采用静态箱—气相色谱法对不施肥对照(CK)、常规施化肥(NPK)、新鲜稻草与化肥配施(RS+NPK1)、菌渣与化肥配施(MR+NPK1)、新鲜牛粪与化肥配施(CD+NPK2)和沼渣与化肥配施(BD+NPK2)等6个处理的CH4和N2O排放通量进行为期一年的观测(早稻、晚稻和休闲期),研究排放特征与驱动因素。结果表明,不同处理的CH4排放均表现出"早稻生长期少,晚稻生长期多,休闲期弱"的特点,而N2O排放主要发生在水稻生长期内(78%以上),休闲期内排放较少。NPK的CH4排放比CK增加了35%,差异不显著(P0.05,P是拒绝原假设的犯错概率)。有机无机配施处理中,RS+NPK1和CD+NPK2的CH4全年累计排放量分别是MR+NPK1和BD+NPK2的2.44和2.45倍(P0.05),但后者的N2O全年累计排放量分别比前者提高了59%和102%(P0.05)。与单施化肥相比,有机无机配施使稻田氮肥N2O-N直接排放系数降低45%～80%。相关环境因素分析表明,水、热变化是驱动稻田CH4排放季节变化的主要因素。本研究未发现水分变化与N2O排放通量之间存在直接联系,而且CH4和N2O在排放时间上不存在消长关系。CH4和N2O的整体温室效应表明,CH4是当地双季稻田的主要温室气体。采用腐熟后的菌渣和沼渣代替新鲜的稻草和牛粪还田可以使稻田CH4排放量降低约60%,CH4和N2O的整体温室效应降低约50%,而稻谷产量保持不变。
DOI:10.3864/j.issn.0578-1752.2012.23.011URLMagsci [本文引用: 1]
【目的】研究生物质炭对连续两年稻田土壤性质、水稻产量和痕量温室气体排放的影响，为合理施用生物质炭而促进水稻生产可持续的低碳发展提供科学依据。【方法】选择成都平原稻田，2010年布设了施氮与否（0与240 kg N•hm-2）下生物质炭土壤施用（0、20、40 t•hm-2）试验，连续两年观测土壤性质、水稻产量、土壤CH4和N2O排放的变化。【结果】施氮肥条件下，生物质炭连续两年对主要土壤肥力性质表现出改善效应，提高了土壤有机碳、全氮含量和pH，同时降低土壤容重，但对水稻产量影响不显著。生物质炭对CH4排放的影响依氮肥施用而异。不施氮肥下，施用生物质炭提高当季土壤CH4排放（20 t•hm-2用量时），但次年无影响。施用氮肥下，不同用量生物质炭对土壤CH4排放无显著影响，仅40 t•hm-2用量时次年CH4排放有所增加；生物质炭对不施氮肥土壤当季N2O排放无显著影响，并降低次年的排放。然而，施氮肥下，生物质炭连续两年显著降低了土壤N2O的排放，其降幅高达66%。施氮肥条件下，连续两年生物质炭处理降低稻田痕量温室气体的综合温室效应及其水稻生产的碳强度，特别是40 t•hm-2的高用量下。【结论】在连续两年内，稻田采用生物质炭配施氮肥的管理措施对改善土壤性质和稳定水稻产量具有持续效应，高用量生物质炭(40 t•hm-2)显著降低稻田CH4和N2O痕量温室气体排放的综合温室效应和水稻生产的碳强度，且在连续两年内具有稳定的持续性。因此，在当前稻田管理措施下，生物质炭施用量为40 t•hm-2可实现稻田稳产和固碳减排的目标。
DOI:10.3864/j.issn.0578-1752.2012.23.011URLMagsci [本文引用: 1]
【目的】研究生物质炭对连续两年稻田土壤性质、水稻产量和痕量温室气体排放的影响，为合理施用生物质炭而促进水稻生产可持续的低碳发展提供科学依据。【方法】选择成都平原稻田，2010年布设了施氮与否（0与240 kg N•hm-2）下生物质炭土壤施用（0、20、40 t•hm-2）试验，连续两年观测土壤性质、水稻产量、土壤CH4和N2O排放的变化。【结果】施氮肥条件下，生物质炭连续两年对主要土壤肥力性质表现出改善效应，提高了土壤有机碳、全氮含量和pH，同时降低土壤容重，但对水稻产量影响不显著。生物质炭对CH4排放的影响依氮肥施用而异。不施氮肥下，施用生物质炭提高当季土壤CH4排放（20 t•hm-2用量时），但次年无影响。施用氮肥下，不同用量生物质炭对土壤CH4排放无显著影响，仅40 t•hm-2用量时次年CH4排放有所增加；生物质炭对不施氮肥土壤当季N2O排放无显著影响，并降低次年的排放。然而，施氮肥下，生物质炭连续两年显著降低了土壤N2O的排放，其降幅高达66%。施氮肥条件下，连续两年生物质炭处理降低稻田痕量温室气体的综合温室效应及其水稻生产的碳强度，特别是40 t•hm-2的高用量下。【结论】在连续两年内，稻田采用生物质炭配施氮肥的管理措施对改善土壤性质和稳定水稻产量具有持续效应，高用量生物质炭(40 t•hm-2)显著降低稻田CH4和N2O痕量温室气体排放的综合温室效应和水稻生产的碳强度，且在连续两年内具有稳定的持续性。因此，在当前稻田管理措施下，生物质炭施用量为40 t•hm-2可实现稻田稳产和固碳减排的目标。
[本文引用: 2]
[本文引用: 2]
DOI:10.11654/jaes.2016.02.026URL [本文引用: 3]
为比较秸秆和生物质炭对土壤氧化亚氮排放的影响，利用室内培养试验研究生物质炭、秸秆添加对土壤性质、硝化作用及N2O排放的影响。试验设生物质炭、秸秆和空白3个处理，试验培养条件为30℃和75%田间持水量。结果表明，添加秸秆和生物质炭显著提高土壤pH、有机碳和速效K含量，其中秸秆对土壤pH的增加作用更为突出。与对照（1604.82±168.93μgN2O-N·kg-1）相比，添加秸秆和生物质炭减少N2O排放量分别为58.0%和65.6%，但二者减排机理不同；秸秆对N2O的减排因生物的氮固定，降低了硝化反应底物的有效性，生物质炭对N2O减排可能源于硝化过程中较低的N2O产生比例。由于生物质炭显著促进土壤硝化速率，而产生较多的NO-3，使得热带地区砖红壤硝态氮的淋失风险增大。
DOI:10.11654/jaes.2016.02.026URL [本文引用: 3]
为比较秸秆和生物质炭对土壤氧化亚氮排放的影响，利用室内培养试验研究生物质炭、秸秆添加对土壤性质、硝化作用及N2O排放的影响。试验设生物质炭、秸秆和空白3个处理，试验培养条件为30℃和75%田间持水量。结果表明，添加秸秆和生物质炭显著提高土壤pH、有机碳和速效K含量，其中秸秆对土壤pH的增加作用更为突出。与对照（1604.82±168.93μgN2O-N·kg-1）相比，添加秸秆和生物质炭减少N2O排放量分别为58.0%和65.6%，但二者减排机理不同；秸秆对N2O的减排因生物的氮固定，降低了硝化反应底物的有效性，生物质炭对N2O减排可能源于硝化过程中较低的N2O产生比例。由于生物质炭显著促进土壤硝化速率，而产生较多的NO-3，使得热带地区砖红壤硝态氮的淋失风险增大。
DOI:10.5846/stxb201607281546URL [本文引用: 2]
以华北农田冬小麦-夏玉米轮作体系连续6a施用生物炭和秸秆还田的土壤为研究对象,于2013年10月—2014年9月,采用静态暗箱-气相色谱法,对CO_2、N_2O通量进行了整个轮作周期的连续观测,探究施用生物炭与秸秆还田对其排放通量的影响。试验共设4个处理:CK(对照)、C1(低量生物炭4.5 t hm~(-2)a~(-1))、C2(高量生物炭9.0 t hm~(-2)a~(-1))和SR(秸秆还田straw return)。结果表明:在整个轮作周期内,各处理CO_2、N_2O通量随时间的变化趋势基本一致。随着生物炭施用量的增加,CO_2排放通量分别增加了0.3%—90.3%(C1)、1.0%—334.2%(C2)和0.4%—156.3%(SR)。其中,C2处理对CO_2累积排放量影响最大,增幅为42.9%。对N_2O而言,C2处理显著降低了N_2O累积排放量,但增加了CO_2和N_2O排放的综合增温潜势,C1和SR处理对N_2O累积排放量及综合增温潜势均没有显著影响。相关分析表明,土壤温度和土壤含水量是影响CO_2通量最主要的因素,两者之间呈极显著的正相关关系;N_2O通量与土壤温度、土壤含水量、NO_3~--N和NH_4~+-N均表现出极显著的正相关关系,而与土壤p H值表现出极显著的负相关关系。由此可见,添加生物炭对于减少氮素的气体损失具有较大的潜力。
DOI:10.5846/stxb201607281546URL [本文引用: 2]
以华北农田冬小麦-夏玉米轮作体系连续6a施用生物炭和秸秆还田的土壤为研究对象,于2013年10月—2014年9月,采用静态暗箱-气相色谱法,对CO_2、N_2O通量进行了整个轮作周期的连续观测,探究施用生物炭与秸秆还田对其排放通量的影响。试验共设4个处理:CK(对照)、C1(低量生物炭4.5 t hm~(-2)a~(-1))、C2(高量生物炭9.0 t hm~(-2)a~(-1))和SR(秸秆还田straw return)。结果表明:在整个轮作周期内,各处理CO_2、N_2O通量随时间的变化趋势基本一致。随着生物炭施用量的增加,CO_2排放通量分别增加了0.3%—90.3%(C1)、1.0%—334.2%(C2)和0.4%—156.3%(SR)。其中,C2处理对CO_2累积排放量影响最大,增幅为42.9%。对N_2O而言,C2处理显著降低了N_2O累积排放量,但增加了CO_2和N_2O排放的综合增温潜势,C1和SR处理对N_2O累积排放量及综合增温潜势均没有显著影响。相关分析表明,土壤温度和土壤含水量是影响CO_2通量最主要的因素,两者之间呈极显著的正相关关系;N_2O通量与土壤温度、土壤含水量、NO_3~--N和NH_4~+-N均表现出极显著的正相关关系,而与土壤p H值表现出极显著的负相关关系。由此可见,添加生物炭对于减少氮素的气体损失具有较大的潜力。
DOI:10.3864/j.issn.0578-1752.2011.24.006URLMagsci [本文引用: 2]
【目的】对不同有机物料施入红壤后CO2释放特征及几种形态碳、氮变化进行了观测，并分析其相互关系，以阐明添加有机物料后红壤中CO2释放量及几种碳、氮形态的变化特征。【方法】采用室内恒温培养试验，向红壤中添加5种有机物料（猪粪、牛粪、鸡粪、玉米秸秆和小麦秸秆），培养期间定期采样分析红壤CO2释放量及土壤微生物量碳、氮（SMBC、SMBN）的动态变化。【结果】添加有机物料后，各处理CO2释放速率在培养前期较高，在培养18-20 d后基本趋于稳定。整个培养期间，土壤CO2-C的累积过程符合一级反应动力学方程。添加不同有机物料后红壤CO2潜在释放量从高到低顺序为：小麦秸秆（1.51 g•kg-1）＞玉米秸秆（1.38 g•kg-1）＞猪粪（0.89 g•kg-1）＞鸡粪（0.78 g•kg-1）＞牛粪（0.50 g•kg-1）。添加几种有机物料后红壤CO2释放量存在显著差异，秸秆类有机物料分解释放CO2量相当于动物有机肥的2倍以上，其中小麦秸秆最高，牛粪最低，且有机物料分解释放CO2量与SMBC、SMBN、土壤可溶性有机碳（WSOC）和有机物料C/N呈显著相关。【结论】等碳量的有机物料施入红壤后能显著提高土壤CO2的释放速率和释放量，且土壤CO2释放量与土壤微生物量、可溶性碳和有机物料的C/N紧密相关。添加有机物料处理，土壤微生物生物量和碳源、氮源的有效性较高，有利于土壤养分的转化和释放。
DOI:10.3864/j.issn.0578-1752.2011.24.006URLMagsci [本文引用: 2]
【目的】对不同有机物料施入红壤后CO2释放特征及几种形态碳、氮变化进行了观测，并分析其相互关系，以阐明添加有机物料后红壤中CO2释放量及几种碳、氮形态的变化特征。【方法】采用室内恒温培养试验，向红壤中添加5种有机物料（猪粪、牛粪、鸡粪、玉米秸秆和小麦秸秆），培养期间定期采样分析红壤CO2释放量及土壤微生物量碳、氮（SMBC、SMBN）的动态变化。【结果】添加有机物料后，各处理CO2释放速率在培养前期较高，在培养18-20 d后基本趋于稳定。整个培养期间，土壤CO2-C的累积过程符合一级反应动力学方程。添加不同有机物料后红壤CO2潜在释放量从高到低顺序为：小麦秸秆（1.51 g•kg-1）＞玉米秸秆（1.38 g•kg-1）＞猪粪（0.89 g•kg-1）＞鸡粪（0.78 g•kg-1）＞牛粪（0.50 g•kg-1）。添加几种有机物料后红壤CO2释放量存在显著差异，秸秆类有机物料分解释放CO2量相当于动物有机肥的2倍以上，其中小麦秸秆最高，牛粪最低，且有机物料分解释放CO2量与SMBC、SMBN、土壤可溶性有机碳（WSOC）和有机物料C/N呈显著相关。【结论】等碳量的有机物料施入红壤后能显著提高土壤CO2的释放速率和释放量，且土壤CO2释放量与土壤微生物量、可溶性碳和有机物料的C/N紧密相关。添加有机物料处理，土壤微生物生物量和碳源、氮源的有效性较高，有利于土壤养分的转化和释放。
DOI:10.13227/j.hjkx.2015.07.048URL [本文引用: 1]
秸秆还田后作物残体的分解是农田生态系统碳循环及养分周转平衡的一个至关重要环节.为了探索秸秆化学性质和土壤质地对黑土区土壤CO2排放和微生物量的影响,本文通过室内恒温培养实验研究了添加不同植株部位玉米秸秆(根、茎下部、茎顶部、叶)进入黑土区两种质地土壤(砂壤土和黏壤土)后的CO2排放、微生物量,并分析了它们与秸秆C/N、木质素含量的关系.结果表明,添加不同部位秸秆一致增加土壤CO2排放量,激发效应值介于216.53~335.17μmol·g-1,黏壤土大于砂壤土.激发效应值与木质素/N之间的线性回归关系明显好于激发效应与木质素含量、C/N、含氮量之间的线性关系.添加秸秆增加MBC和MBN含量,降低MBC/MBN,微生物群落氮固持的速率高于碳固持.添加秸秆后,砂壤土微生物量增加的幅度大于黏壤土,总溶解性氮含量小于黏壤土.结果说明,秸秆的木质素和氮含量均会对它的分解和CO2排放产生影响,木质素/N比木质素含量、C/N等更好地说明秸秆分解和CO2排放的差异;与黏壤土相比,在砂壤土中实施秸秆还田可以取得更好的土壤碳固存、微生物量和氮素保持效果.
DOI:10.13227/j.hjkx.2015.07.048URL [本文引用: 1]
秸秆还田后作物残体的分解是农田生态系统碳循环及养分周转平衡的一个至关重要环节.为了探索秸秆化学性质和土壤质地对黑土区土壤CO2排放和微生物量的影响,本文通过室内恒温培养实验研究了添加不同植株部位玉米秸秆(根、茎下部、茎顶部、叶)进入黑土区两种质地土壤(砂壤土和黏壤土)后的CO2排放、微生物量,并分析了它们与秸秆C/N、木质素含量的关系.结果表明,添加不同部位秸秆一致增加土壤CO2排放量,激发效应值介于216.53~335.17μmol·g-1,黏壤土大于砂壤土.激发效应值与木质素/N之间的线性回归关系明显好于激发效应与木质素含量、C/N、含氮量之间的线性关系.添加秸秆增加MBC和MBN含量,降低MBC/MBN,微生物群落氮固持的速率高于碳固持.添加秸秆后,砂壤土微生物量增加的幅度大于黏壤土,总溶解性氮含量小于黏壤土.结果说明,秸秆的木质素和氮含量均会对它的分解和CO2排放产生影响,木质素/N比木质素含量、C/N等更好地说明秸秆分解和CO2排放的差异;与黏壤土相比,在砂壤土中实施秸秆还田可以取得更好的土壤碳固存、微生物量和氮素保持效果.
DOI:10.2112/JCOASTRES-D-09-00120.1URLPMID:21046997 [本文引用: 1]
A field experiment was conducted for two years on a sandy loam (Typic Ustochrept) soil of Punjab to study the effect of organic materials and rice cultivars on methane emission from rice fields. The methane flux varied between 0.04 and 0.93 mg m-2 hr-1 in bare soil and transplanting of rice crop doubled the methane flux (0.07 to 2.06 mg m-2 hr-1). Among rice cultivars, significantly (p < 0.05) higher amount of methane was emitted from Pusa 44 compared to PR 118 and PR 111. Application of organic materials enhanced methane emission from rice fields and resulted in increased soil organic carbon content. The greatest seasonal methane flux was observed in wheat straw amended plots (229.6 kg ha-1) followed by farmyard manure (111.6 kg ha-1), green manure (85.4 kg ha-1) and the least from rice straw compost amended plots (36.9 kg ha-1) as compared to control (21.5 kg ha-1). The differential effect of organic materials in enhancing methane flux was related to total carbon or C:N ratio of the material. The results showed that incorporation of humified organic matter such as rice straw compost could minimize methane emission from rice fields with co-benefits of increased soil fertility and crop productivity.
DOI:10.1007/s00374-012-0711-4URL [本文引用: 3]
Amending vegetable soils with organic materials is increasingly recommended as an agroecosystems management option to improve soil quality. However, the amounts of NO, N2O, and N-2 emissions from vegetable soils treated with organic materials and frequent irrigation are not known. In laboratory-based experiments, soil from a NO (3) (-) -rich (340 mg N kg(-1)) vegetable field was incubated at 30A degrees C for 30 days, with and without 10 % C2H2, at 50, 70, or 90 % water-holding capacity (WHC) and was amended at 1.19 g C kg(-1) (equivalent to 2.5 t C ha(-1)) as Chinese milk vetch (CMV), ryegrass (RG), or wheat straw (WS); a soil not amended with organic material was used as a control (CK). At 50 % WHC, cumulative N-2 production (398-524 mu g N kg(-1)) was significantly higher than N2O (84.6-190 mu g N kg(-1)) and NO (196-224 mu g N kg(-1)) production, suggesting the occurrence of denitrification under unsaturated conditions. Organic materials and soil water content significantly influenced NO emissions, but the effect was relatively weak since the cumulative NO production ranged from 124 to 261 mu g N kg(-1). At 50-90 % WHC, the added organic materials did not affect the accumulated NO (3) (-) in vegetable soil but enhanced N2O emissions, and the effect was greater by increasing soil water content. At 90 % WHC, N2O production reached 13,645-45,224 mu g N kg(-1) from soil and could be ranked as RG > CMV > WS > CK. These results suggest the importance of preventing excess water in soil while simultaneously taking into account the quality of organic materials applied to vegetable soils.
DOI:10.1016/j.atmosenv.2013.02.009URL [本文引用: 1]
Crop residue returning is a common practice in agricultural system that consequently influences nitrous oxide (N2O) emissions. Much attention has been focused on the effects of crop residue on N2O release. However, no systematic result has yet been drawn because environmental factors among different studies vary. A meta-analysis was described to integrate 112 scientific assessments of crop residue returning on N2O emissions in this study. Results showed that crop residue returning, when averaged across all studies, had no statistically significant effect on N2O release compared with control treatments. However, the range of effects of crop residue returning on N2O emission was significantly affected by synthetic nitrogen (N) fertilizer application, type of crop residue, specific manner in which crop residue has returned, and type of land-use. N2O release was significantly inhibited by 11.7% and 27.1% (P < 0.05) when crop residue was with synthetic N fertilizer and when type of land-use was paddy, respectively. While N2O emissions were significantly enhanced by 42.1% and 23.5% (P < 0.05) when crop residue was applied alone and when type of land-use was upland, respectively. N2O emissions were likewise increased when crop residue with lower C/N ratio was used, mulching of crop residue was performed, and type of land-use was fallow. Our study provides the first quantitative analysis of crop residue returning on N2O emissions, indicating that crop residue returning has no statistically significant effect on N2O release at regional scale, and underlining that the Intergovernmental Panel on Climate Change guidelines should take the opposite effects of crop residue returning on upland and paddy into account when estimating the N2O emission factor of crop residue for different land-use types. Given that most of data are dominated by certain types of crop residue and specific application methods, more field data are required to reduce uncertainty.
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DOI:10.1046/j.1365-2389.2001.00415.xURL [本文引用: 1]
Summary Despite decades of research to define optimal chamber design and deployment protocol for measuring gas exchange between the Earth's surface and the atmosphere, controversy still surrounds the procedures for applying this method. Using a numerical simulation model we demonstrated that (i) all non-steady-state chambers should include a properly sized and properly located vent tube; (ii) even seemingly trivial leakiness of the seals between elements of a multiple-component chamber results in significant risk of measurement error; (iii) a leaking seal is a poor substitute for a properly designed vent tube, because the shorter path length through the seal supports much greater diffusive gas loss per unit of conductance to mass flow; (iv) the depth to which chamber walls must be inserted to minimize gas loss by lateral diffusion is smaller than is customary in fine-textured, wet or compact soil, but much larger than is customary in highly porous soils, and (v) repetitive sampling at the same location is not a major source of error when using non-steady-state chambers. Finally, we discuss problems associated with computing the flux of a gas from the non-linear increase in its concentration in the headspace of a non-steady-state chamber.
[R].
[本文引用: 1]
北京: 中国大地出版社,
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Beijing: China Land Press,
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DOI:10.1016/S1002-0160(12)60013-7URL [本文引用: 1]
DOI:10.1007/BF00384434URL [本文引用: 1]
We determined the size, activity, and affinity of the microbial community for glucose in soils from long-term experimental grassland plots. The plots had been treated annually with either farmyard manure, inorganic NPK fertilizers, farmyard manure+inorganic NPK fertilizers, (NH 4 ) 2 SO 4 only, or no experimental amendment sine 1897. The largest biomass and activity differences were between the (NH 4 ) 2 SO 4 -treated soil, which was very acid, and the rest, which were nearer neutral. In the (NH 4 ) 2 SO 4 -treated soil, the biomass C to organic C ratio was small, but overall the community had high respiratory activity per unit of biomass ( q CO 2 ) and high overall affinity for glucose (low K m ). The effects of the manure treatment were a greater biomass C and a lower overall glucose affinity than in the control plot. In the presence farmyard manure, NPK led to smaller biomass and a lower biomass to organic C ratio while having no significant effect on either glucose K m or q CO 2 . In the absence of farmyard manure, NPK led to significantly greater glucose affinity but had no significant effect on the biomass, the biomass C to organic C ratio or q CO 2 .
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DOI:10.3864/j.issn.0578-1752.2015.21.018URL [本文引用: 1]
[目的]等施氮量条件下,比较有机肥与化肥田间施用后农田温室气体(CO2和N2O)的排放量及其增温潜势,正确认识有机肥与化肥在田间温室气体排放过程中的贡献,为制定田间合理的减排措施提供理论依据。[方法]在华北平原冬小麦-夏玉米种植制度下,以8年的长期定位试验为平台,利用静态箱-气相色谱法,于2014年6—10月,持续监测了化肥和有机肥在不同施肥水平下潮土玉米季土壤N2O和CO2的排放特征,并估算玉米季温室气体排放量及其产生的综合温室效应。[结果]施用有机肥与化肥农田土壤N2O的排放通量变化基本一致,施肥后出现短暂的排放高峰,之后逐渐趋于平稳;等氮条件下,化肥处理的N2O日排放通量明显高于有机肥处理,峰值过后的稳定期内有机肥处理的N2O排放通量略高于化肥处理。化肥的施用对农田土壤CO2的排放规律影响不明显,有机肥施用后CO2会出现持续的排放高峰。施用有机肥与化肥均会增加N2O的排放总量,且随施氮增加N2O排放总量显著增加;等氮量条件下,化肥处理的N2O排放总量显著高于有机肥。有机肥处理显著增加了农田土壤CO2的排放量,而化肥对CO2排放总量的影响不明显。施氮量为240kg·hm-2时,有机肥和化肥处理作物产量均达到较高水平,而温室气体的排放强度(GHGI)最低,分别为0.27、0.63 kg·hm-2,高于此施氮量,有机肥和化肥处理的GHGI均会明显增加。[结论]大量施用有机肥和化肥都会产生过多的温室气体。由于有机肥的固碳效应,化肥处理GHGI高于有机肥处理,适量施用有机肥是实现农田固碳减排的重要途径。
DOI:10.3864/j.issn.0578-1752.2015.21.018URL [本文引用: 1]
[目的]等施氮量条件下,比较有机肥与化肥田间施用后农田温室气体(CO2和N2O)的排放量及其增温潜势,正确认识有机肥与化肥在田间温室气体排放过程中的贡献,为制定田间合理的减排措施提供理论依据。[方法]在华北平原冬小麦-夏玉米种植制度下,以8年的长期定位试验为平台,利用静态箱-气相色谱法,于2014年6—10月,持续监测了化肥和有机肥在不同施肥水平下潮土玉米季土壤N2O和CO2的排放特征,并估算玉米季温室气体排放量及其产生的综合温室效应。[结果]施用有机肥与化肥农田土壤N2O的排放通量变化基本一致,施肥后出现短暂的排放高峰,之后逐渐趋于平稳;等氮条件下,化肥处理的N2O日排放通量明显高于有机肥处理,峰值过后的稳定期内有机肥处理的N2O排放通量略高于化肥处理。化肥的施用对农田土壤CO2的排放规律影响不明显,有机肥施用后CO2会出现持续的排放高峰。施用有机肥与化肥均会增加N2O的排放总量,且随施氮增加N2O排放总量显著增加;等氮量条件下,化肥处理的N2O排放总量显著高于有机肥。有机肥处理显著增加了农田土壤CO2的排放量,而化肥对CO2排放总量的影响不明显。施氮量为240kg·hm-2时,有机肥和化肥处理作物产量均达到较高水平,而温室气体的排放强度(GHGI)最低,分别为0.27、0.63 kg·hm-2,高于此施氮量,有机肥和化肥处理的GHGI均会明显增加。[结论]大量施用有机肥和化肥都会产生过多的温室气体。由于有机肥的固碳效应,化肥处理GHGI高于有机肥处理,适量施用有机肥是实现农田固碳减排的重要途径。
URL [本文引用: 1]
氧化亚氮(N2O)作为一种重要的温室气体,其全球排放总量仍然在持续上升.它不仅可以产生温室效应,还可以间接破坏臭氧层,使其在全球气候变化和生态环境变化研究中备受关注.土壤生态系统是大气中N2O的最重要排放源.本文详细论述了农田土壤中反硝化作用、硝化作用、硝化微生物的反硝化作用以及硝酸盐异化还原成铵作用等过程产生N2O的微生物学机制,并从土壤理化性质(土壤pH、氮素、有机质、土壤温度和湿度)和土壤生物等方面对农田土壤N2O排放的影响进行综述,在此基础上对农田土壤N2O的减排措施进行总结,并就今后农田土壤N2O排放的研究重点和方向进行了展望,为调控农田土壤温室气体排放、氮转化过程和提高氮素利用效率提供科学依据.
URL [本文引用: 1]
氧化亚氮(N2O)作为一种重要的温室气体,其全球排放总量仍然在持续上升.它不仅可以产生温室效应,还可以间接破坏臭氧层,使其在全球气候变化和生态环境变化研究中备受关注.土壤生态系统是大气中N2O的最重要排放源.本文详细论述了农田土壤中反硝化作用、硝化作用、硝化微生物的反硝化作用以及硝酸盐异化还原成铵作用等过程产生N2O的微生物学机制,并从土壤理化性质(土壤pH、氮素、有机质、土壤温度和湿度)和土壤生物等方面对农田土壤N2O排放的影响进行综述,在此基础上对农田土壤N2O的减排措施进行总结,并就今后农田土壤N2O排放的研究重点和方向进行了展望,为调控农田土壤温室气体排放、氮转化过程和提高氮素利用效率提供科学依据.
DOI:10.1016/j.jclepro.2013.04.033URL [本文引用: 1]
61This study analyzed soil carbon sequestration based on long-term tillage experiment and DNDC model simulation.61Carbon footprint including farm input, GHG emissions and crops yields was studied.61No tillage can be an important innovation for C-friendly and cleaner technology in North China.
DOI:10.1002/jsfa.7196URLPMID:25847361 [本文引用: 2]
BACKGROUND Crop residue management and nitrogen loss are two important environmental problems in the rice–wheat rotation system in China. This study investigated the effects of burial of straw on water percolation, nitrogen loss by leaching, crop growth and yield. Greenhouse mesocosm experiments were conducted over the course of three simulated cropping seasons in a rice1–wheat–rice2 rotation. RESULTS Greater amounts of straw resulted in more water percolation, irrespective of crop season. Burial at 20 and 3565cm significantly reduced, but burial at 5065cm increased nitrogen leaching. Straw at 50065kg65ha611 reduced, but at 100065kg65ha611 and at 150065kg65ha611 straw increased nitrogen leaching in three consecutive crop rotations. In addition, straw at 50065kg65ha611 buried at 3565cm significantly increased yield and its components for both crops. CONCLUSIONS This study suggests that N losses via leaching from the rice–wheat rotation may be reduced by the burial of the appropriate amount of straw at the appropriate depth. Greater amounts of buried straw, however, may promote nitrogen leaching and negatively affect crop growth and yields. Complementary field experiments must be performed to make specific agronomic recommendations. 08 2015 Society of Chemical Industry
DOI:10.1016/j.agee.2009.08.003URL [本文引用: 1]
Agricultural production plays an important role in affecting atmospheric greenhouse gas concentrations. Field measurements were conducted in Quzhou County, Hebei Province in the North China Plains to quantify carbon dioxide (CO 2) and nitrous oxide (N 2O) emissions from a winter wheat aize rotation field, a common cropping system across the Chinese agricultural regions. The observed flux data in conjunction with the local climate, soil and management information were utilized to test a process-based model, Denitrification ecomposition or DNDC, for its applicability for the cropping system. The validated DNDC was then used for predicting impacts of three management alternatives (i.e., no-till, increased crop residue incorporation and reduced fertilizer application rate) on CO 2 and N 2O emissions from the target field. Results from the simulations indicated that (1) CO 2 emissions were significantly affected by temperature, initial SOC, tillage method, and quantity and quality of the organic matter added in the soils; (2) increases in temperature, initial SOC, total fertilizer N input, and manure amendment substantially increased N 2O emissions; and (3) temperature, initial SOC, tillage, and quantity and quality of the organic matter added in the soil all had significant effects on global warming. Finally, five 50-year scenarios were simulated with DNDC to predict their long-term impacts on crop yield, soil C dynamics, nitrate leaching losses, and N 2O emissions. The modelled results suggested that implementation of manure amendment or crop residue incorporation instead of increased fertilizer application rates would more efficiently mitigate GHG emissions from the tested agro-ecosystem. The multi-impacts provided a sound basis for comprehensive assessments on the management alternatives.
DOI:10.1016/j.soilbio.2012.03.017URL [本文引用: 1]
Biochar application to soil has significant potential as a climate change mitigation strategy, due to its recalcitrant C content and observed effect to suppress soil greenhouse gas emissions such as nitrous oxide (N2O). Increased soil aeration following biochar amendment may contribute to this suppression. Soil cores from a Miscanthus X. giganteus plantation were amended with hardwood biochar at a rate of 2% dry soil weight (2202t02ha611). The cores were incubated at three different temperatures (4, 10 and 1602°C) for 126 days, maintained field moist and half subjected to periodic wetting events. Cumulative N2O production was consistently suppressed by at least 49% with biochar amendment within 4802h of wetting at 10 and 1602°C. We concluded that hardwood biochar suppressed soil N2O emissions following wetting at a range of field-relevant temperatures over four months. We hypothesised that this was due to biochar increasing soil aeration at relatively high moisture contents by increasing the water holding capacity (WHC) of the soil; however, this hypothesis was rejected. We found that 5% and 10% biochar amendment increased soil WHC. Also, 10% biochar amendment decreased bulk density of the soil. Sealed incubations were performed with biochar added at 0–10 % of dry soil weight and wetted to a uniform 87% WHC (78% WFPS). Cumulative N2O production within 6002h of wetting was 19, 19, 73 and 98% lower than the biochar-free control in the 1, 2, 5 and 10% biochar treatments respectively. We conclude that high levels of biochar amendment may change soil physical properties, but that the enhancement of soil aeration by biochar incorporation makes only a minimal contribution to the suppression of N2O emissions from a sandy loam soil. We suggest that microbial or physical immobilisation of NO361 in soil following biochar addition may significantly contribute to the suppression of soil N2O emissions.
DOI:10.1038/18205URL [本文引用: 1]
Humans have altered global nitrogen cycling such that more atmospheric Nis being converted (`fixed') into biologically reactive forms by anthropogenic activities than by all natural processes combined. In particular, nitrogen oxides emitted during fuel combustion and ammonia volatilized as a result of intensive agriculture have increased atmospheric nitrogen inputs (mostly NOand NH) to temperate forests in the Northern Hemisphere. Because tree growth in northern temperate regions is typically nitrogen-limited, increased nitrogen deposition could have the effect of attenuating rising atmospheric COby stimulating the accumulation of forest biomass. Forest inventories indicate that the carbon contents of northern forests have increased concurrently with nitrogen deposition since the 1950s. In addition, variations in atmospheric COindicate a globally significant carbon sink in northern mid-latitude forest regions. It is unclear, however, whether elevated nitrogen deposition or other factors are the primary cause of carbon sequestration in northern forests. Here we use evidence from N-tracer studies in nine forests to show that elevated nitrogen deposition is unlikely to be a major contributor to the putative COsink in forested northern temperature regions.
DOI:10.1016/j.foreco.2004.03.011URL [本文引用: 2]
DOI:10.13930/j.cnki.cjea.160678URL [本文引用: 3]
菌渣是栽培食用菌后的下脚料,可作为有机肥再利用.本文通过实验室条件下培养不同比例的菌渣和稻田土壤混合物[不施用菌渣(TS),土壤与菌渣质量比为10∶1(SM1)、5∶ 1(SM2)和2∶1(SM3),全部菌渣(TM)],研究不同处理有机碳和全氮的变化,探讨菌渣在稻田土壤中的分解过程,并分析CO2释放特征,为菌渣合理利用提供参考.结果表明,在相同培养时间,添加不同比例菌渣处理有机碳和氮含量均比TS处理高,其中TM处理的有机碳和全氮分别比TS处理提高了10.7倍和11.0倍.有机碳、氮含量的提高量主要依赖于菌渣的添加量.总体来说,各处理随培养时间的延长,由于碳氮的分解,有机碳、氮均有下降趋势;在35 d后TM处理有机碳氮下降较快.添加菌渣越多,有机碳残留率也越大.在培养63 d后,菌渣有机碳(Yc)和氮(YN)的分解残留率与菌渣添加量(X)的关系式分别为:Yc=71.26X-0.607 5,r2=1.000 0**和YN=74.039X-0.413 3,r2=0.999 9**.各处理土壤CO2释放速率均表现出先增后降然后趋于稳定趋势.菌渣用量越高,CO2释放速率越高,各处理在不同培养时间CO2释放速率均表现为TM＞SM3＞SM2＞SM1 ＞TS.在第7d时各处理CO2释放速率最高,在第14d时渐渐处于平稳下降状态,培养35 d后,各处理土壤有机碳矿化强度很小,大部分有机碳被固定在土壤中,其中TM处理有机碳矿化强度最小.总之,还田菌渣越多,土壤中被固定的碳越多.
DOI:10.13930/j.cnki.cjea.160678URL [本文引用: 3]
菌渣是栽培食用菌后的下脚料,可作为有机肥再利用.本文通过实验室条件下培养不同比例的菌渣和稻田土壤混合物[不施用菌渣(TS),土壤与菌渣质量比为10∶1(SM1)、5∶ 1(SM2)和2∶1(SM3),全部菌渣(TM)],研究不同处理有机碳和全氮的变化,探讨菌渣在稻田土壤中的分解过程,并分析CO2释放特征,为菌渣合理利用提供参考.结果表明,在相同培养时间,添加不同比例菌渣处理有机碳和氮含量均比TS处理高,其中TM处理的有机碳和全氮分别比TS处理提高了10.7倍和11.0倍.有机碳、氮含量的提高量主要依赖于菌渣的添加量.总体来说,各处理随培养时间的延长,由于碳氮的分解,有机碳、氮均有下降趋势;在35 d后TM处理有机碳氮下降较快.添加菌渣越多,有机碳残留率也越大.在培养63 d后,菌渣有机碳(Yc)和氮(YN)的分解残留率与菌渣添加量(X)的关系式分别为:Yc=71.26X-0.607 5,r2=1.000 0**和YN=74.039X-0.413 3,r2=0.999 9**.各处理土壤CO2释放速率均表现出先增后降然后趋于稳定趋势.菌渣用量越高,CO2释放速率越高,各处理在不同培养时间CO2释放速率均表现为TM＞SM3＞SM2＞SM1 ＞TS.在第7d时各处理CO2释放速率最高,在第14d时渐渐处于平稳下降状态,培养35 d后,各处理土壤有机碳矿化强度很小,大部分有机碳被固定在土壤中,其中TM处理有机碳矿化强度最小.总之,还田菌渣越多,土壤中被固定的碳越多.
DOI:10.1021/es9031419URLPMID:20099810 [本文引用: 1]
Abstract Char black carbon (BC), the solid residue of incomplete combustion, is continuously being added to soils and sediments due to natural vegetation fires, anthropogenic pollution, and new strategies for carbon sequestration ("biochar"). Here we present a molecular-level assessment of the physical organization and chemical complexity of biomass-derived chars and, specifically, that of aromatic carbon in char structures. Brunauer-Emmett-Teller (BET)-N(2) surface area (SA), X-ray diffraction (XRD), synchrotron-based near-edge X-ray absorption fine structure (NEXAFS), and Fourier transform infrared (FT-IR) spectroscopy are used to show how two plant materials (wood and grass) undergo analogous but quantitatively different physical-chemical transitions as charring temperature increases from 100 to 700 degrees C. These changes suggest the existence of four distinct categories of char consisting of a unique mixture of chemical phases and physical states: (i) in transition chars, the crystalline character of the precursor materials is preserved; (ii) in amorphous chars, the heat-altered molecules and incipient aromatic polycondensates are randomly mixed; (iii) composite chars consist of poorly ordered graphene stacks embedded in amorphous phases; and (iv) turbostratic chars are dominated by disordered graphitic crystallites. Molecular variations among the different char categories likely translate into differences in their ability to persist in the environment and function as environmental sorbents.
DOI:10.3969/j.issn.10017216.2013.01.014Magsci [本文引用: 1]
通过向水稻土中添加秸秆和黑炭进行水稻盆栽实验（秸秆的添加量为2 g/kg和10 g/kg，黑炭的添加量为5 g/kg和25 g/kg），分别在孕穗期和成熟期取样研究土壤碳氮转化及微生物代谢剖面的变化。对土壤有机碳、全氮、铵氮等含量的测定结果显示，秸秆和黑炭均能于一定程度上促进土壤碳氮转化，提高水稻产量；Microresp方法检测的微生物代谢图谱表明，秸秆和黑炭的添加量越大，对微生物的代谢影响越大。造成这些差异的主要原因是添加秸秆和黑炭后微生物对果糖、丙氨酸、乙酰葡萄糖胺和赖氨酸盐酸盐的利用率上升。另外，秸秆对微生物碳和净碳矿化速率的影响显著高于黑炭，而黑炭对水稻产量和土壤固碳的影响更大。
DOI:10.3969/j.issn.10017216.2013.01.014Magsci [本文引用: 1]
通过向水稻土中添加秸秆和黑炭进行水稻盆栽实验（秸秆的添加量为2 g/kg和10 g/kg，黑炭的添加量为5 g/kg和25 g/kg），分别在孕穗期和成熟期取样研究土壤碳氮转化及微生物代谢剖面的变化。对土壤有机碳、全氮、铵氮等含量的测定结果显示，秸秆和黑炭均能于一定程度上促进土壤碳氮转化，提高水稻产量；Microresp方法检测的微生物代谢图谱表明，秸秆和黑炭的添加量越大，对微生物的代谢影响越大。造成这些差异的主要原因是添加秸秆和黑炭后微生物对果糖、丙氨酸、乙酰葡萄糖胺和赖氨酸盐酸盐的利用率上升。另外，秸秆对微生物碳和净碳矿化速率的影响显著高于黑炭，而黑炭对水稻产量和土壤固碳的影响更大。
[本文引用: 1]
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DOI:10.13227/j.hjkx.201701002URL [本文引用: 3]
以位于西南大学农业部重庆紫色土生态环境重点野外科学观测试验站内辣椒-萝卜轮作菜地为研究对象,采用静态暗箱/气相色谱法,通过1 a的田间原位观测,研究地膜覆盖对菜地生态系统土壤的水热条件、CH4排放通量及各土层CH4剖面浓度的影响.结果表明,地膜覆盖能显著提高春夏辣椒种植季的土壤温度(P0.05);覆膜种植土壤含水率在萝卜季显著高于常规种植(P0.05);在整个观测周期内,覆膜和常规种植条件下,土壤CH4的排放通量均无明显变化规律,CH4排放通量的均值分别为-7.64μg?(m2?h)-1和-9.00μg?(m2?h)-1,整个观测期CH4净吸收量分别为0.54 kg?hm-2和0.64 kg?hm-2,表明地膜覆盖在一定程度上能削弱土壤作为CH4汇的能力.在各土层CH4浓度观测方面,发现两种种植方式在整个观测周期内各土层CH4浓度变化趋势大致相同,表现为:10 cm>20 cm>30 cm,覆膜土壤CH4浓度在20 cm、30 cm深土层显著低于常规种植(P0.05).相关性分析结果表明,覆膜种植土壤CH4的排放通量与5 cm地温显著正相关(P<0.05),与土壤含水率之间显著负相关(P<0.05),而在常规种植条件下,CH4排放通量与地表温度、5 cm地温及土壤含水率均无相关性;两处理10 cm、20 cm土层CH4浓度均与地表CH4浓度呈显著正相关(P<0.01),30 cm土层CH4浓度与地表温度及5 cm地温均呈显著正相关,各土层CH4浓度与土壤含水率无显著相关关系.
DOI:10.13227/j.hjkx.201701002URL [本文引用: 3]
以位于西南大学农业部重庆紫色土生态环境重点野外科学观测试验站内辣椒-萝卜轮作菜地为研究对象,采用静态暗箱/气相色谱法,通过1 a的田间原位观测,研究地膜覆盖对菜地生态系统土壤的水热条件、CH4排放通量及各土层CH4剖面浓度的影响.结果表明,地膜覆盖能显著提高春夏辣椒种植季的土壤温度(P0.05);覆膜种植土壤含水率在萝卜季显著高于常规种植(P0.05);在整个观测周期内,覆膜和常规种植条件下,土壤CH4的排放通量均无明显变化规律,CH4排放通量的均值分别为-7.64μg?(m2?h)-1和-9.00μg?(m2?h)-1,整个观测期CH4净吸收量分别为0.54 kg?hm-2和0.64 kg?hm-2,表明地膜覆盖在一定程度上能削弱土壤作为CH4汇的能力.在各土层CH4浓度观测方面,发现两种种植方式在整个观测周期内各土层CH4浓度变化趋势大致相同,表现为:10 cm>20 cm>30 cm,覆膜土壤CH4浓度在20 cm、30 cm深土层显著低于常规种植(P0.05).相关性分析结果表明,覆膜种植土壤CH4的排放通量与5 cm地温显著正相关(P<0.05),与土壤含水率之间显著负相关(P<0.05),而在常规种植条件下,CH4排放通量与地表温度、5 cm地温及土壤含水率均无相关性;两处理10 cm、20 cm土层CH4浓度均与地表CH4浓度呈显著正相关(P<0.01),30 cm土层CH4浓度与地表温度及5 cm地温均呈显著正相关,各土层CH4浓度与土壤含水率无显著相关关系.
URL [本文引用: 1]
URL [本文引用: 1]
DOI:10.3724/SP.J.1011.2013.00297URL [本文引用: 2]
研究不同农业管理措施下小麦农田N2O、CO2、CH4等温室气体的综合增温潜势,有助于科学评价农业管理措施在减少温室气体排放和减缓全球变暖方面的作用,为制定温室气体减排措施提供依据。本研究采用静态明箱气相色谱法对华北平原高产农区4种农业管理措施下冬小麦农田土壤温室气体(CO2、CH4和N2O)季节排放通量进行了监测,估算了不同农业管理措施下小麦季的综合温室效应。结果表明,华北太行山前平原冬小麦农田土壤是CO2、N2O的排放源,CH4的吸收汇。不同农业管理措施对不同温室气体的排放源和吸收汇强度的影响不同,增施氮肥、充分灌溉促进了土壤CO2、N2O的生成,强化了土壤CO2和N2O排放源的特征;但却抑制了土壤对CH4的氧化,弱化了土壤作为大气CH4吸收汇的特征。2009—2010年和2010—2011年冬小麦生长季T1(传统模式)、T2(高产高效模式)、T3(再高产模式)和T4(再高产高效和土壤生产力提高模式)处理土壤排放的温室气体碳当量分别依次为8 880 kg(CO2).hm 2、8 372 kg(CO2).hm 2、9 600 kg(CO2).hm 2、9 318kg(CO2).hm 2和13 395 kg(CO2).hm 2、12 904 kg(CO2).hm 2、13 933 kg(CO2).hm 2、13 189 kg(CO2).hm 2。各处理间温室气体排放差异主要是由于施肥和灌溉措施的不同引起的,秸秆还田与否是造成年度间温室气体排放存在差异的主要原因。T2处理综合增温潜势相对较低,产量和产投比相对较高,为本区域冬小麦优化管理模式。
DOI:10.3724/SP.J.1011.2013.00297URL [本文引用: 2]
研究不同农业管理措施下小麦农田N2O、CO2、CH4等温室气体的综合增温潜势,有助于科学评价农业管理措施在减少温室气体排放和减缓全球变暖方面的作用,为制定温室气体减排措施提供依据。本研究采用静态明箱气相色谱法对华北平原高产农区4种农业管理措施下冬小麦农田土壤温室气体(CO2、CH4和N2O)季节排放通量进行了监测,估算了不同农业管理措施下小麦季的综合温室效应。结果表明,华北太行山前平原冬小麦农田土壤是CO2、N2O的排放源,CH4的吸收汇。不同农业管理措施对不同温室气体的排放源和吸收汇强度的影响不同,增施氮肥、充分灌溉促进了土壤CO2、N2O的生成,强化了土壤CO2和N2O排放源的特征;但却抑制了土壤对CH4的氧化,弱化了土壤作为大气CH4吸收汇的特征。2009—2010年和2010—2011年冬小麦生长季T1(传统模式)、T2(高产高效模式)、T3(再高产模式)和T4(再高产高效和土壤生产力提高模式)处理土壤排放的温室气体碳当量分别依次为8 880 kg(CO2).hm 2、8 372 kg(CO2).hm 2、9 600 kg(CO2).hm 2、9 318kg(CO2).hm 2和13 395 kg(CO2).hm 2、12 904 kg(CO2).hm 2、13 933 kg(CO2).hm 2、13 189 kg(CO2).hm 2。各处理间温室气体排放差异主要是由于施肥和灌溉措施的不同引起的,秸秆还田与否是造成年度间温室气体排放存在差异的主要原因。T2处理综合增温潜势相对较低,产量和产投比相对较高,为本区域冬小麦优化管理模式。
DOI:10.1111/j.1574-6941.2006.00127.xURLPMID:16907749 [本文引用: 2]
The effect of nitrogen (N) additions on the dynamics of carbon monoxide consumption in temperate forest soils is poorly understood. We measured soil CO profiles, potential rates of CO consumption and uptake kinetics in temperate hardwood and pine control plots and plots amended with 50 and 150 kg N ha 0908081 year 0908081 for more than 15 years. Soil profiles of CO concentrations were above atmospheric levels in the high-N plots of both stands, suggesting that in these forest soils the balance between consumption and production may be shifted so that either production is increased or consumption decreased. Highest rates of CO consumption were measured in the organic horizon and decreased with soil depth. In the N-amended plots, CO consumption increased in all but one soil depth of the hardwood stand, but decreased in all soil depths of the pine stand. CO enzyme affinities increased with soil depth in the control plots. However, enzyme affinities in the most active soil depths (organic and 00900095 cm mineral) decreased in response to low levels of N in both stands. In the high-N plots, affinities dramatically-increased in the hardwood stand, but decreased in the organic horizon and increased slightly in the 00900095 cm mineral soil in the pine stand. These findings indicate that long-term N addition either by fertilization or deposition may alter the size, composition and/or physiology of the community of CO consumers so that their ability to act as a sink for atmospheric CO has changed. This change could have a substantial effect on the lifetime of greenhouse gases such as CH 4 and therefore the future of Earth's climate.
DOI:10.1016/j.agrformet.2010.10.008URL [本文引用: 1]
Quantifying the nitrous oxide (N 2O) and nitric oxide (NO) fluxes emitted from croplands remains a major challenge. Field measurements in different climates, soil and agricultural conditions are still scarce and emissions are generally assessed from a small number of measurements. In this study, we report continuously measured N 2O and NO fluxes with a high temporal resolution over a 2-year crop sequence of barley and maize in northern France. Measurements were carried out using 6 automatic chambers at a rate of 16 mean flux measurements per day. Additional laboratory measurements on soil cores were conducted to study the response of NO and N 2O emissions to environmental conditions. The detection limit of the chamber setup was found to be 3 ng N m 612 s 611 for N 2O and 0.1 ng N m 612 s 611 for NO. Nitrous oxide fluxes were higher than the threshold 37% of the time, while they were 72% of the time for NO fluxes. The cumulated annual NO and N 2O emissions were 1.7 kg N 2O-N ha 611 and 0.5 kg NO-N ha 611 in 2007, but 2.9 kg N 2O-N ha 611 and 0.7 kg NO-N ha 611 in 2008. These inter-annual differences were largely related to crop types and to their respective management practices. The forms, amounts and timing of nitrogen applications and the mineralization of organic matter by incorporation of crop residues were found to be the main factor controlling the emissions peaks. The inter-annual variability was also due to different weather conditions encountered in 2007 and 2008. In 2007, the fractioned N inputs applied on barley (54 kg ha 611 in March and in April) did not generate N 2O emissions peaks because of the low rainfall during the spring. However, the significant rainfall observed in the summer and fall of 2007, promoted rapid decomposition of barley residues which caused high levels of N 2O emissions. In 2008, the application of dairy cattle slurry and mineral fertilizer before the emergence of maize (107 kg N min ha 611 or 130 kg N tot ha 611 in all) coincided with large rainfalls promoting both NO and N 2O emissions, which remained high until early summer. Laboratory measurements corroborated the field observations: NO fluxes were maximum at a water-filled pore space (WFPS) of around 27% while N 2O fluxes were optimal at 68% WFPS, with a maximum potentially 14 times larger than for NO.
DOI:10.1134/S1064229310080090URL [本文引用: 1]
The effect of the temperature and moisture on the emission of N 2 O from arable soils was studied in model experiments with arable soils at three contrasting levels of wetting and in a wide temperature range (from 615 to +25°C), including freeze-thaw cycles. It was shown that the losses of fertilizer nitrogen from the soils with water contents corresponding to 60 and 75% of the total water capacity (TWC) did not exceed 0.01–0.09% in the entire temperature range. In the soils with an elevated water content (90% of the TWC) at 25°C, the loss of fertilizer nitrogen in the form of N 2 O reached 2.35% because of the active denitrification. The extra N 2 O flux initiated by the freeze-thaw processes made up 88–98% of the total nitrous oxide flux during the entire experiment.
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DOI:10.1038/ngeo686URL [本文引用: 1]
Climate change negotiations aim to reduce net greenhouse-gas emissions by encouraging direct reductions of emissions and crediting countries for their terrestrial greenhouse-gas sinks. Ecosystem carbon dioxide uptake has offset nearly 10% of Europe's fossil fuel emissions, but not all of this may be creditable under the rules of the Kyoto Protocol. Although this treaty recognizes the importance of methane and nitrous oxide emissions, scientific research has largely focused on carbon dioxide. Here we review recent estimates of European carbon dioxide, methane and nitrous oxide fluxes between 2000 and 2005, using both top-down estimates based on atmospheric observations and bottom-up estimates derived from ground-based measurements. Both methods yield similar fluxes of greenhouse gases, suggesting that methane emissions from feedstock and nitrous oxide emissions from arable agriculture are fully compensated for by the carbon dioxide sink provided by forests and grasslands. As a result, the balance for all greenhouse gases across Europe's terrestrial biosphere is near neutral, despite carbon sequestration in forests and grasslands. The trend towards more intensive agriculture and logging is likely to make Europe's land surface a significant source of greenhouse gases. The development of land management policies which aim to reduce greenhouse-gas emissions should be a priority.
DOI:10.1038/nature03226URL [本文引用: 1]
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DOI:10.11766/trxb201407160357URL [本文引用: 1]
A field experiment was carried out in a paddy field under rice-wheat rotation, to study effects of biochar amended at the rice or wheat season on paddy CH and NO emissions throughout the cycle of rotation, their consequential global warming potential (GWP) and greenhouse gas intensity (GHGI), with a view to providing some scientific basis for extrapolation of the use biochar in mitigating global warming potentials and in agricultural production as well. The field experiment was designed to last an entire cycle of crop rotation, that is, two cropping seasons, rice season and wheat season, and to have eight treatments in triplicate, i.e. Treatment RB-N or CK (zero N fertilizer applied & zero biochar amended in the rice season), Treatment RB-N (250 kg hm N fertilizer applied & zero biochar amended in the rice season), Treatment RB-N (250 kg hm N fertilizer applied & 20 t hm biochar amended in the rice season), Treatment RB2-N1 (250 kg hm N fertilizer applied & 40 t hm-2 biochar amendment at rice season), Treatment WB-N (zero N fertilizer applied & zero biochar amended in the wheat season), Treatment WB-N (250 kg hm N fertilizer applied & biochar amended in the wheat season), Treatment WB-N (250 kg hmN fertilizer applied & 20 t hm biochar amended in the wheat season), and Treatment WB-N (250 kg hm N fertilizer applied & 40 t hm biochar amended in the wheat season). Biochar was amended before rice transplanting on June 10, 2012 and wheat seeding on November 10, 2012. CH and NO gas emission fluxes were monitored with the static chamber and gas chromatography method. Results show that Relative to Treatment RB-N Treatment RB-N did not have much significant effect on NO and CH emissions, GWP and GHGI, while Treatment RB-N significantly improved crop yield by 17.2%, and significantly reduced total CH emissions and GWP by 8.6% and 9.3%, respectively. Treatment WB-N did not have much effect on GHGI and GWP, but did increase wheat yield by 21.6%, which in turn significantly reduced GHGI by 21.7%. Treatment WB-N significantly reduced NO and CHemissions by 20.9% and 11.3%, respectively and GWP and GHGI by 15.7% and 23.5%, respectively. In terms of total GWP on a 100-year horizon, the treatments followed an order of RB-N > RB-N > WB-N > WB-N > RB-N > WB-N > RB-N > RB-N, while in terms of GWPs per unit crop grain yield, they followed another, i.e. RB-N > WB-N > RB-N > RB-N > RB-N > WB-N > WB-N > WB-N. Obviously biochar application is more effective in the wheat season than in the rice season, in reducing NO and CH emissions, lowering the GWP and GHGI and increasing crop yield of the rotation system. Although Treatment WBN was lower than Treatment WBN in NO and CH emission, and also in wheat yield which to use depends on balance between GHG mitigation and grain yield. However, consequential effects and underlying mechanisms of the use of biochar in the field on scale need further field study Results incorporation at rice season had no significant difference on NO and CHemissions, GWP and GHGI. Relative to the RB-N treatment, the RB-Ntreatment significantly improved crop yield by 17.2%, significantly reduced the total CH emissions and GWP by 8.6% and 9.3%, respectively. The crop yield of biochar incorporation at wheat season with 20 t h significantly improved by 21.6%, and significantly reduced 21.7% GHGI compare with WB-N. Biochar incorporation at wheat season with 40 t h significantly reduced NO and CH CHmissions by 20.9% and 11.3%, respectively, significantly reduced GWP and GHGI by 15.7% and 23.5%, respectively. Biochar application at wheat season was better than rice season. iochar incorporation at wheat season on improved crop production, reduced NO and CH emissions, while simultaneously lower the GWP and GHGI were superior to the biochar incorporation at rice season in the rice-wheat rotation system.
DOI:10.11766/trxb201407160357URL [本文引用: 1]
A field experiment was carried out in a paddy field under rice-wheat rotation, to study effects of biochar amended at the rice or wheat season on paddy CH and NO emissions throughout the cycle of rotation, their consequential global warming potential (GWP) and greenhouse gas intensity (GHGI), with a view to providing some scientific basis for extrapolation of the use biochar in mitigating global warming potentials and in agricultural production as well. The field experiment was designed to last an entire cycle of crop rotation, that is, two cropping seasons, rice season and wheat season, and to have eight treatments in triplicate, i.e. Treatment RB-N or CK (zero N fertilizer applied & zero biochar amended in the rice season), Treatment RB-N (250 kg hm N fertilizer applied & zero biochar amended in the rice season), Treatment RB-N (250 kg hm N fertilizer applied & 20 t hm biochar amended in the rice season), Treatment RB2-N1 (250 kg hm N fertilizer applied & 40 t hm-2 biochar amendment at rice season), Treatment WB-N (zero N fertilizer applied & zero biochar amended in the wheat season), Treatment WB-N (250 kg hm N fertilizer applied & biochar amended in the wheat season), Treatment WB-N (250 kg hmN fertilizer applied & 20 t hm biochar amended in the wheat season), and Treatment WB-N (250 kg hm N fertilizer applied & 40 t hm biochar amended in the wheat season). Biochar was amended before rice transplanting on June 10, 2012 and wheat seeding on November 10, 2012. CH and NO gas emission fluxes were monitored with the static chamber and gas chromatography method. Results show that Relative to Treatment RB-N Treatment RB-N did not have much significant effect on NO and CH emissions, GWP and GHGI, while Treatment RB-N significantly improved crop yield by 17.2%, and significantly reduced total CH emissions and GWP by 8.6% and 9.3%, respectively. Treatment WB-N did not have much effect on GHGI and GWP, but did increase wheat yield by 21.6%, which in turn significantly reduced GHGI by 21.7%. Treatment WB-N significantly reduced NO and CHemissions by 20.9% and 11.3%, respectively and GWP and GHGI by 15.7% and 23.5%, respectively. In terms of total GWP on a 100-year horizon, the treatments followed an order of RB-N > RB-N > WB-N > WB-N > RB-N > WB-N > RB-N > RB-N, while in terms of GWPs per unit crop grain yield, they followed another, i.e. RB-N > WB-N > RB-N > RB-N > RB-N > WB-N > WB-N > WB-N. Obviously biochar application is more effective in the wheat season than in the rice season, in reducing NO and CH emissions, lowering the GWP and GHGI and increasing crop yield of the rotation system. Although Treatment WBN was lower than Treatment WBN in NO and CH emission, and also in wheat yield which to use depends on balance between GHG mitigation and grain yield. However, consequential effects and underlying mechanisms of the use of biochar in the field on scale need further field study Results incorporation at rice season had no significant difference on NO and CHemissions, GWP and GHGI. Relative to the RB-N treatment, the RB-Ntreatment significantly improved crop yield by 17.2%, significantly reduced the total CH emissions and GWP by 8.6% and 9.3%, respectively. The crop yield of biochar incorporation at wheat season with 20 t h significantly improved by 21.6%, and significantly reduced 21.7% GHGI compare with WB-N. Biochar incorporation at wheat season with 40 t h significantly reduced NO and CH CHmissions by 20.9% and 11.3%, respectively, significantly reduced GWP and GHGI by 15.7% and 23.5%, respectively. Biochar application at wheat season was better than rice season. iochar incorporation at wheat season on improved crop production, reduced NO and CH emissions, while simultaneously lower the GWP and GHGI were superior to the biochar incorporation at rice season in the rice-wheat rotation system.
