生物炭配施氮肥对典型黄河故道区土壤理化性质和冬小麦产量的影响

探讨典型黄河故道区生物炭配施氮肥对耕层土壤理化性质和作物产量的影响,阐明生物炭配施氮肥后土壤碳氮含量和理化性质的变化规律,可为合理培肥土壤、提升耕地质量、提高冬小麦产量提供科学依据。本研究以黄河故道典型区域潮土和中性生物炭为供试材料,连续两年进行田间定位试验,开展不同生物炭用量(0、15、30 t·hm^-2)配施氮肥(N 270、330 kg·hm^-2)对土壤理化性质的影响研究。结果表明: 生物炭施入2年后,土壤广义土壤结构指数(GSSI)增大、土壤三相结构距离指数(STPSD)减小,显著改善了土壤三相比,其中在30 t·hm^-2施炭量条件下土壤三相比最接近理想状态;土壤紧实度和容重降低,土壤总孔隙度和毛管孔隙度增加,田间持水量和透水透气性增大,土壤板结状况得到缓解;>0.25 mm粒径团聚体显著增加(增幅70.6%～94.4%),团聚体平均重量直径(MWD)增大(增幅24.0%～48.0%),土壤团聚体结构得到改善。施加生物炭可显著增加土壤有机碳含量(增幅15.8%～67.0%),并可调节土壤C/N,降低氮素释放强度,提高氮肥利用率,显著增加土壤肥力,但未提高土壤pH值,其中10～20 cm土层土壤pH值呈显著下降趋势。在相同施氮条件下,施用生物炭比不施用处理的冬小麦产量2年平均增加9.6%～25.6%,增产效果显著;在相同生物炭施用量下,高氮处理比常规氮处理的冬小麦平均增产2.5%～4.4%,但差异不显著。综上,生物炭配施氮肥能够改善土壤微生态环境,提高土壤肥力,增加作物产量。从改善土壤理化性质、作物增产效果和投入成本等方面综合考虑,推荐在黄河故道区耕作层施入生物炭30 t·hm^-2并配施氮肥330 kg·hm^-2较为适宜。     

生物炭施用3年后对稻麦轮作系统CH4和N2O综合温室效应的影响

本试验对比观测研究了在稻田土壤中经3年陈化后的生物炭(B₃)和新施入生物炭(B₀)对稻麦轮作系统CH₄和N₂O综合温室效应和温室气体强度的影响,旨在明确生物炭对土壤温室气体排放的长期效应.田间试验设置4个处理,分别为对照(CK)、施用氮肥不施用生物炭(N)、施用氮肥和新生物炭(NB₀)以及施用氮肥和陈化生物炭(NB₃)处理.结果表明: NB₀和NB₃处理均显著提高了稻田土壤pH值、有机碳和全氮含量,并且显著影响与温室气体排放相关的微生物潜在活性.与N处理相比,NB₃处理显著增加了作物产量,增幅14.1%,并且显著降低了CH₄和N₂O排放,降幅分别为9.0%和34.0%;而NB₀处理显著增加作物产量,增幅9.3%,显著降低N₂O排放,降幅38.6%,但增加了CH₄排放,增幅4.7%;同时NB₀和NB₃处理均能降低稻麦轮作系统的综合温室效应和温室气体强度,且NB₃处理能更有效地减少温室气体的排放并提高作物产量.在土壤中经3年陈化后的生物炭仍然具有固碳减排能力,因此,施用生物炭对稻麦轮作系统固碳减排和改善作物生产具有长期效应.     

施用生物炭6年后对稻田土壤酶活性及肥力的影响

利用田间定位试验,研究0(BC₀)、7.5(BC₁)、15(BC₂)和22.5(BC₃)t·hm^-2水稻秸秆生物炭及3.75 t·hm^-2水稻秸秆(STR)一次性施加6年后对稻田土壤肥力及酶活性的影响.结果表明: 施用生物炭6年后土壤有机碳、有效磷和速效钾含量显著增加,增幅分别为34.6%、12.4%和26.2%,土壤pH值和容重显著降低,但对土壤全氮含量无显著影响.土壤脲酶和酸性磷酸酶的活性显著增加,土壤荧光素二乙酸酯酶(FDA水解酶)和芳基硫酸酯酶的活性受到不同程度的抑制,其中,BC₂处理的土壤脲酶活性增加量最大,增幅为36.5%.土壤酸性磷酸酶活性随着生物炭施加量的增加而增加,与土壤速效磷含量呈显著正相关关系;土壤FDA水解酶和脲酶主要与土壤速效钾含量有关;酸性磷酸酶和芳基硫酸酯酶与土壤容重呈显著正相关.施用生物炭6年后土壤脱氢酶和多酚氧化酶活性明显升高,增幅分别为48.8%和27.5%,而过氧化氢酶活性逐渐下降,且显著低于对照BC₀.STR处理显著增加了土壤脲酶、FDA水解酶、脱氢酶、酸性磷酸酶和芳基硫酸酯酶的活性,降低了过氧化氢酶和多酚氧化酶的活性,降幅分别为23.4%和15.9%.     

生物炭施用3年后对稻麦轮作系统CH4和N2O综合温室效应的影响

本试验对比观测研究了在稻田土壤中经3年陈化后的生物炭(B_3)和新施入生物炭(B_0)对稻麦轮作系统CH_4和N_2O综合温室效应和温室气体强度的影响,旨在明确生物炭对土壤温室气体排放的长期效应.田间试验设置4个处理,分别为对照(CK)、施用氮肥不施用生物炭(N)、施用氮肥和新生物炭(NB_0)以及施用氮肥和陈化生物炭(NB_3)处理.结果表明:NB_0和NB_3处理均显著提高了稻田土壤pH值、有机碳和全氮含量,并且显著影响与温室气体排放相关的微生物潜在活性.与N处理相比,NB_3处理显著增加了作物产量,增幅14.1%,并且显著降低了CH_4和N_2O排放,降幅分别为9.0%和34.0%;而NB_0处理显著增加作物产量,增幅9.3%,显著降低N_2O排放,降幅38.6%,但增加了CH_4排放,增幅4.7%;同时NB_0和NB_3处理均能降低稻麦轮作系统的综合温室效应和温室气体强度,且NB_3处理能更有效地减少温室气体的排放并提高作物产量.在土壤中经3年陈化后的生物炭仍然具有固碳减排能力,因此,施用生物炭对稻麦轮作系统固碳减排和改善作物生产具有长期效应.     

生物炭对塿土水热特性及团聚体稳定性的影响

试验设生物炭用量为0 (B₀)、20 (B₂₀)、40 (B₄₀)、60 (B₆₀)、80 (B₈₀) t·hm^-2 5个处理,研究了施用果树树干、枝条生物炭2年后,对塿土容重、含水率、土壤温度和团聚体稳定性及其分布的影响.结果表明： 在0～30 cm土层,施炭处理与B₀相比,土壤容重显著降低7.7%～10.9%;土壤含水率显著增加10.0%～13.4%;施用40～60 t·hm^-2生物炭可以缓冲土壤的温度变化,提高土壤的保温性能;大于0.25 mm的水稳性团聚体（WR_0.25）显著增加30.3%;平均质量直径（MWD）在干筛、湿筛条件下分别显著增加15.2%和31.6%;团聚体破坏率（PAD）和不稳定团粒指数（E_LT）分别显著降低19.1%和17.5%.说明生物炭的施用明显改善了塿土的水热特性,提高了团聚体的含量和稳定性;其施用量为40～60 t·hm^-2时综合表现较优.     

生物炭对玉米/大豆、玉米/花生间作系统土壤水肥热及产量的影响

于2019年5—9月在沈阳农业大学水利学院科研试验基地进行田间试验,设置2种种植模式MS、MP(玉米/大豆间作、玉米/花生间作)和3个生物炭施用量T0、T1和T2(0、15和30 t·hm^-2)的田间小区试验,研究施入生物炭对玉米/大豆、玉米/花生间作系统土壤水热、养分吸收和产量的影响。结果表明:施入生物炭对作物生育初期0~30 cm土壤储水量影响不显著,随着生育期的推进,由于受降雨等因素的影响,生物炭处理显著提高了0~30 cm土壤储水量,其中在抽雄期MPT2处理的增幅最大,达15.49%;在苗期与拔节期,由于降雨少,生物炭对30~60 cm土壤储水量的影响并不显著,从抽雄期开始至生育末期表现出显著性差异,但提升效果不如0~30 cm土层。生物炭可以显著提高苗期与拔节期土壤有效积温,在苗期MPT2处理下提升效果最为显著,增幅达20.97%,而在作物生育中后期,生物炭对土壤有效积温的影响减弱,在抽雄期和灌浆期的影响最小。生物炭施入土壤后虽然显著降低了作物生育前期土壤的矿质氮含量,但显著提高了作物生长发育中后期的矿质氮含量(25.19%~48.82%),因而增加了MS总产量(12.79%~13.71%)和MP总产量(15.86%~18.01%)。因此,生物炭有效调控了作物生长发育关键期土壤的水肥热状况,改善了间作系统的作物生长环境,使得间作这一本来就有着产量优势的种植模式产生了更大的增产效应。     

连续施用炭基肥及生物炭对棕壤有机氮组分的影响

为了揭示连续施用炭基肥及生物炭条件下棕壤有机氮组分的变化情况,本文基于田间定位试验,研究了连续定位施用炭基肥及生物炭对棕壤有机氮组分的影响。试验共设置5个处理:不施肥、低量生物炭、高量生物炭、氮磷钾配施、炭基肥。于2014年花生收获后每个小区按"S"型设置3个采样点,采集0~20、20~40 cm的土壤样本,利用Branmer有机氮分组方法对土壤有机氮组分进行测定与分析。结果表明:经过连续4年的不同施肥处理,不同处理土壤全氮含量均有所提升;炭基肥处理土壤全氮含量显著高于原始土和CK处理,增幅分别达到69.8%、4.8%;不同施肥处理中有机氮各组分的含量顺序为酸解铵态氮氨基酸态氮非酸解氮酸解未知态氮氨基糖态氮;施用炭基肥显著增加了土壤酸解有机氮中酸解铵态氮、氨基酸态氮的含量,与原始土相比增加了65.9%、128.0%;随着生物炭用量的增加,酸解铵态氮含量处于增加趋势,但增加幅度远低于等碳投入的炭基肥处理;对于未知态氮、非酸解有机氮总量无论施用生物炭、氮磷钾化肥或炭基肥均提高了其含量,但各处理间差异不显著;连续施用炭基肥或生物炭显著提高了土壤酸解有机氮中酸解铵态氮和氨基酸态氮的含量,促进了氮素的活化,有利于花生中低产田氮素的吸收和运转。     

酸性稻田添加生物炭对水稻生长发育及产量的影响——基于5年大田试验

开展生物炭对农田生态系统长期效应的大田试验对全面评价生物炭调控农田生产力的效果具有重要意义。以南方酸性稻田为对象,采用单因素随机区组设计开展了5年大田试验,探讨不同水平生物炭(0、20、40、60、80 t/hm~2和100 t/hm~2)一次性添加对水稻生长和产量的多年效应。主要结果为:(1)水稻齐穗期的LAI、倒4叶叶绿素含量及地上部干物质积累量和产量均随生物炭添加量增加而增加;(2)生物炭对齐穗期剑叶叶绿素含量以及粒叶比的影响不显著;(3)生物炭显著促进稻田增产的添加量分别为:≥60 t/hm~2(增幅17.0%—23.7%,第1年)、≥40 t/hm~2(增幅15.5%—32.4%,第2年)、20—100 t/hm~2(增幅9.6%—21.8%,第3年)、均无显著差异(第4年)、100 t/hm~2(增幅15.7%、第5年);(4)生物炭对稻田累计产量的增幅分别为:5.9%—23.7%(第1年)、5.5%—27.8%(第2年)、6.8%—25.9%(第3年)、5.4%—22.0%(第4年)、4.6%—20.6%(第5年);(5)产量与齐穗期的LAI、倒4叶叶绿素含量、干物质积累量及每穗粒数显著正相关。综上表明:酸性稻田生物炭一次性添加有利于改善水稻群体质量,促进稻田增产,高炭量添加(80 t/hm~2和100 t/hm~2)相比于中低炭量添加持续增产效应更好,至少可稳定维持3年。研究结果可为指导生产实践中利用生物炭以实现稻田增产提供科技支撑。     

生物炭对植烟土壤微生态和烤烟生理的影响

生物炭是农林废弃物资源化利用的研究热点之一.通过田间试验,研究了烟杆炭不同施用量(0、1、10、50 t·hm^-2)对植烟土壤微生态和烤烟生理特性的影响.结果表明: 烤烟各时期土壤含水量均随生物炭用量增加而增加;在烤烟旺长阶段,50 t·hm^-2处理的土壤含水量显著高于其他处理.随着生物炭用量的增加,土壤总孔隙度和毛管孔隙度逐渐增加,细菌、放线菌、真菌的数量表现为先增后减的趋势,其中生物炭用量10 t·hm^-2处理下数值最大.土壤早期呼吸速率随生物炭用量的增加而增大,与对照相比,生物炭处理土壤呼吸速率增幅为7.9%～36.9%,生物炭高用量(50和10 t·hm^-2)与对照差异显著.生物炭提升了烤烟叶片水势,增加了叶片类胡萝卜素和叶绿素含量,显著增加了根系、地上部和总干质量.说明生物炭在改良植烟土壤微生态和调控烤烟生理特性等方面具有积极效应.     

施用南荻生物炭对不同类型土壤氨挥发的影响

在洞庭湖区农田施用秸秆生物炭不仅能实现秸秆资源化利用,还可降低环境污染压力。本研究于2020年采用水稻盆栽试验,研究了不同南荻秸秆生物炭施用量对土壤氨挥发速率、累积氨挥发量、表面水pH值和NH₄⁺-N浓度的影响。供试土壤为第四纪红土发育的红黄泥和花岗岩发育的麻砂泥水稻土,设置6个南荻秸秆生物炭添加处理,即分别以土柱0～20 cm土壤重量的0%、1%、2%、4%、6%和8%比例添加生物炭,每盆施用复合肥200 kg N·hm^-2。结果表明: 施用生物炭导致两种土壤之间或不同生物炭处理之间的氨挥发速率和累积量均存在显著差异。麻砂泥施用生物炭处理在施肥后第2天出现氨挥发峰值,且较不施生物炭处理峰值降低了23.6%～53.4%;红黄泥氨挥发峰值出现在施肥后第7～13天,且其峰值随着生物炭添加量的增加而升高。整体上,麻砂泥土壤的氨挥发速率均高于红黄泥。麻砂泥土壤＜4%生物炭添加量能抑制土壤氨挥发速率及累积量,其中以2%处理降幅最大(46.9%),但生物炭添加对水稻生长前期表面水pH值的影响不显著;红黄泥土壤随着南荻生物炭用量的增加,表面水中pH值和NH₄⁺-N浓度增加,导致氨挥发速率及累积量增幅达1.3～10.5倍。回归分析显示,生物炭添加量是影响两种土壤氨挥发的关键因素。Elo-vich方程能较好地拟合两种土壤的氨挥发累积量随时间的变化动态,各施炭处理的相关系数均达极显著水平。总体上,对于偏中性的麻砂泥土壤,施用一定量的南荻生物炭对氨排放有一定的抑制作用,而对于酸性的红黄泥土壤,增施南荻生物炭会通过提高表面水的pH值和NH₄⁺-N浓度促进氨挥发,因此针对不同类型土壤施用南荻秸秆生物炭应注意选择适宜用量,以降低氮素损失。     

Successive straw biochar application as a strategy to sequester carbon and improve fertility: A pot experiment with two rice/wheat rotations in paddy soil

Aims

A pot study spanning four consecutive crop seasons was conducted to compare the effects of successive rice straw biochar/rice straw amendments on C sequestration and soil fertility in rice/wheat rotated paddy soil.

Methods

We adopted 4.5 t ha^?1, 9.0 t ha^?1 biochar and 3.75 t ha^?1 straw for each crop season with an identical dose of NPK fertilizers.

Results

We found no major losses of biochar-C over the 2-year experimental period. Obvious reductions in CH₄ emission were observed from rice seasons under the biochar application, despite the fact that the biochar brought more C into the soil than the straw. N₂O emissions with biochar were similar to the controls without additives over the 2-year experimental period. Biochar application had positive effects on crop growth, along with positive effects on nutrient (N, P, K, Ca and Mg) uptake by crop plants and the availability of soil P, K, Ca and Mg. High levels of biochar application over the course of the crop rotation suppressed NH₃ volatilization in the rice season, but stimulated it in the wheat season.

Conclusions

Converting straw to biochar followed by successive application to soil is viable for soil C sequestration, CH₄ mitigation, improvements of soil and crop productivity. Biochar soil amendment influences NH₃ volatilization differently in the flooded rice and upland wheat seasons, respectively.     

Response of soil carbon dioxide fluxes,soil organic carbon and microbial biomass carbon to biochar amendment: a meta‐analysis

Biochar as a carbon‐rich coproduct of pyrolyzing biomass, its amendment has been advocated as a potential strategy to soil carbon (C) sequestration. Updated data derived from 50 papers with 395 paired observations were reviewed using meta‐analysis procedures to examine responses of soil carbon dioxide (CO₂) fluxes, soil organic C (SOC), and soil microbial biomass C (MBC) contents to biochar amendment. When averaged across all studies, biochar amendment had no significant effect on soil CO₂ fluxes, but it significantly enhanced SOC content by 40% and MBC content by 18%. A positive response of soil CO₂ fluxes to biochar amendment was found in rice paddies, laboratory incubation studies, soils without vegetation, and unfertilized soils. Biochar amendment significantly increased soil MBC content in field studies, N‐fertilized soils, and soils with vegetation. Enhancement of SOC content following biochar amendment was the greatest in rice paddies among different land‐use types. Responses of soil CO₂ fluxes and MBC to biochar amendment varied with soil texture and pH. The use of biochar in combination with synthetic N fertilizer and waste compost fertilizer led to the greatest increases in soil CO₂ fluxes and MBC content, respectively. Both soil CO₂ fluxes and MBC responses to biochar amendment decreased with biochar application rate, pyrolysis temperature, or C/N ratio of biochar, while each increased SOC content enhancement. Among different biochar feedstock sources, positive responses of soil CO₂ fluxes and MBC were the highest for manure and crop residue feedstock sources, respectively. Soil CO₂ flux responses to biochar amendment decreased with pH of biochar, while biochars with pH of 8.1–9.0 had the greatest enhancement of SOC and MBC contents. Therefore, soil properties, land‐use type, agricultural practice, and biochar characteristics should be taken into account to assess the practical potential of biochar for mitigating climate change.     

Effect of biochar amendment on maize yield and greenhouse gas emissions from a soil organic carbon poor calcareous loamy soil from Central China Plain

Aims

A field experiment was conducted to investigate the effect of biochar on maize yield and greenhouse gases (GHGs) in a calcareous loamy soil poor in organic carbon from Henan, central great plain, China.

Methods

Biochar was applied at rates of 0, 20 and 40?t?ha^?1 with or without N fertilization. With N fertilization, urea was applied at 300?kg?N ha^?1, of which 60% was applied as basal fertilizer and 40% as supplementary fertilizer during crop growth. Soil emissions of CO₂, CH₄ and N₂O were monitored using closed chambers at 7?days intervals throughout the whole maize growing season (WMGS).

Results

Biochar amendments significantly increased maize production but decreased GHGs. Maize yield was increased by 15.8% and 7.3% without N fertilization, and by 8.8% and 12.1% with N fertilization under biochar amendment at 20?t?ha^?1 and 40?t?ha^?1, respectively. Total N₂O emission was decreased by 10.7% and by 41.8% under biochar amendment at 20?t?ha^?1 and 40?t?ha^?1 compared to no biochar amendment with N fertilization. The high rate of biochar (40?t?ha^?1) increased the total CO₂ emission by 12% without N fertilization. Overall, biochar amendments of 20?t?ha^?1 and 40?t?ha^?1 decreased the total global warming potential (GWP) of CH₄ and N₂O by 9.8% and by 41.5% without N fertilization, and by 23.8% and 47.6% with N fertilization, respectively. Biochar amendments also decreased soil bulk density and increased soil total N contents but had no effect on soil mineral N.

Conclusions

These results suggest that application of biochar to calcareous and infertile dry croplands poor in soil organic carbon will enhance crop productivity and reduce GHGs emissions.     

Amending biochar affected enzyme activities and nitrogen turnover in Phaeozem and Luvisol

Soil nitrogen (N) is a vital source of nutrients for maintaining soil fertility and crop production. However, the effect of biochar application rate on the mechanism of organic N transformation and the contribution of enzyme mineralization is still unclear. Therefore, we conducted two 5-year field experiments in contrasting soils (Phaeozem and Luvisol) with biochar application rate at 0 t hm⁻² (CK, 0), 22.5 t hm⁻² (D₁, 1%), 67.5 t hm⁻² (D₂, 3%), and 112.5 t hm⁻² (D₃, 5%) to investigate the potential effects of biochar application rate on soil organic nitrogen (N) turnover and its linkage to enzymatic mineralization in contrasting soil. The results showed that soil organic carbon (SOC) and microbial biomass nitrogen (MBN) contents, microbial biomass carbon to nitrogen ratio (MBC:MBN) and protease activity are significantly influenced by biochar application rate whereas not by soil type. Ammonium nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃⁻-N) contents, and dehydrogenase activity are significantly changed by soil type whereas not by biochar application rate. Based on the redundancy analysis, we found that organic N fractions are associated with MBN, SOC, and protease in Phaeozem, but related to protease activity in Luvisol. Our findings indicate that organic N turnover is not only related to the bioavailability of N but also requires carbon substrates in Phaeozem, whereas the transformation of organic N in Luvisol is dominated by enzymatic mineralization as the relatively low level of bioavailable N.     

生物炭添加对不同水氮条件下芦苇生长和氮素吸收的影响

生物炭能改良土壤从而促进植物生长和氮素吸收，但其作用效果是否受水氮条件的影响尚不清楚。以湿地植物芦苇为研究对象，在3种氮添加水平（无添加，30 kg hm^-2 a^-1和60 kg hm^-2 a^-1）和两种水分（淹水和非淹水）条件下分别进行生物炭添加和不添加处理，结果表明：（1）生物炭添加能促进芦苇根系生长，在非淹水条件下根系生物量增加了40.5%，在淹水条件下根系生物量增加了20.1%。（2）生物炭添加能促进非淹水条件下芦苇的氮素吸收，能提高淹水条件下芦苇的氮素生产力。（3）生物炭添加加剧了土壤氮素损失，且在非淹水高氮条件下作用最强，可能是由于生物炭促进了芦苇的氮素吸收。芦苇氮素吸收速率与土壤氮损失之间存在显著的正相关关系。因此，在添加生物炭时，需要考虑土壤水分状况和氮素富集程度以及植物的氮素吸收偏好。该研究结果可为生物炭在湿地生态系统中的应用提供参考。     

Comparative efficiency of wheat straw and sugarcane bagasse biochar reduces the cadmium bioavailability to spinach and enhances the microbial activity in contaminated soil

Abstract

Biochar is considered a novel soil amendment for cadmium (Cd) stabilization in contaminated soils. A pot experiment was conducted to examine the efficiency of wheat straw and sugarcane bagasse induced biochar on Cd mobility in soil and its bioavailability to spinach in contaminated soil. Soil pH, Cd contents in plant tissues and microbial biomass were examined. Results showed that Cd was significantly decreased by 30.95% and 20.83% with wheat straw and sugarcane bagasse biochar at 2% application rate respectively, relative to the control. Similarly, Cd contents were decreased in plants shoots by 15.41 and 14.33%, while in roots by 48.3 and 35.54%, when wheat straw and sugarcane biochar were added at 2% application rate respectively. Moreover, soil microbial biomass was significantly increased with the application of all biochar types and their applications rates. Finally, wheat straw biochar at 2% application rate can be considered as an effective approach for Cd stabilization in contaminated soils.     

生物焦对土壤生态系统的影响效应

生物焦是生物残体在厌氧条件下高温裂解产生的,其主要成分为碳,芳香化程度很高,具有孔隙多、比表面积大、电荷密度高、不易分解等特点。目前的一些研究显示,生物焦具有提高土壤阳离子交换量（CEC）和pH、改善土壤肥力和健康状况、增加作物产量、减少温室气体排放等作用。生物焦施于土壤后,还具有增加土壤微生物量、改变土壤微生物群落结构,促进部分微生物生长等影响效应。然而,目前有关生物焦的研究还大都局限于表观效应上,缺乏对其微观内在机制的深入探讨。     

秸秆生物质炭对土壤结构体与活性碳分布、转化酶动力学参数及小麦生长的影响

为探明生物质炭输入土壤后与水稳性团聚体的作用机理,及对土壤活性碳库、微生物活性、作物生长的促进作用。以生物质炭和秸秆碳为外源碳材料,两者等碳量添加条件下,在小麦不同生育期采用湿筛法、电镜扫描、酶动力学方程等方法,测定土壤结构、酶活性、活性有机碳、及小麦产量等指标的响应情况。结果表明:生物质炭添加下,土壤0.25 mm大颗粒团聚体显著增加了16.9%—45.8%;土壤结构体分布以土壤大颗粒团聚体为主,含量约为小颗粒团聚体的2倍。生物质炭少量或适量添加(0.8%或2.4%),土壤微生物量碳增加了9.7%—33.6%,溶解性有机碳降低了12.6%—27.5%;而过量添加下(8%),则呈现正好相反的规律。生物质炭输入下,转化酶动力学参数Km、Vmax、k分别下降了17.3%、17.0%、16.1%。生物质炭适量添加下,小麦产量增加了14.9%—19.1%;秸秆3%和10%添加水平下,小麦产量则下降了37.3%和90.1%。整体而言,生物质炭通过增加0.25 mm大颗粒团聚体的形成及土壤转化酶的活性来促进土壤结构和作物的生长的改善,且生物质炭在2.4%水平下的生物质炭添加改善作用最为突出,有助于研究区域过剩秸秆资源的资源化利用。     

Can biochar reduce soil greenhouse gas emissions from a Miscanthus bioenergy crop?

Energy production from bioenergy crops may significantly reduce greenhouse gas (GHG) emissions through substitution of fossil fuels. Biochar amendment to soil may further decrease the net climate forcing of bioenergy crop production, however, this has not yet been assessed under field conditions. Significant suppression of soil nitrous oxide (N₂O) and carbon dioxide (CO₂) emissions following biochar amendment has been demonstrated in short‐term laboratory incubations by a number of authors, yet evidence from long‐term field trials has been contradictory. This study investigated whether biochar amendment could suppress soil GHG emissions under field and controlled conditions in a Miscanthus × Giganteus crop and whether suppression would be sustained during the first 2 years following amendment. In the field, biochar amendment suppressed soil CO₂ emissions by 33% and annual net soil CO₂ equivalent (eq.) emissions (CO₂, N₂O and methane, CH₄) by 37% over 2 years. In the laboratory, under controlled temperature and equalised gravimetric water content, biochar amendment suppressed soil CO₂ emissions by 53% and net soil CO₂ eq. emissions by 55%. Soil N₂O emissions were not significantly suppressed with biochar amendment, although they were generally low. Soil CH₄ fluxes were below minimum detectable limits in both experiments. These findings demonstrate that biochar amendment has the potential to suppress net soil CO₂ eq. emissions in bioenergy crop systems for up to 2 years after addition, primarily through reduced CO₂ emissions. Suppression of soil CO₂ emissions may be due to a combined effect of reduced enzymatic activity, the increased carbon‐use efficiency from the co‐location of soil microbes, soil organic matter and nutrients and the precipitation of CO₂ onto the biochar surface. We conclude that hardwood biochar has the potential to improve the GHG balance of bioenergy crops through reductions in net soil CO₂ eq. emissions.     

不同磷水平配施生物炭对土壤磷有效性

生物炭在提高土壤磷素有效性及促进作物生长方面具有显著作用,但其效果因土壤类型不同存在较大差异。试验以赤红壤(pH 4.91)和褐土(pH 7.24)为供试土壤,设置3种磷肥水平(0、30、90 kg P·hm^-2,分别以不施磷、低磷、高磷表示)配施稻秆生物炭(0、4%)的大豆盆栽试验,研究了不同磷水平下配施生物炭对土壤磷有效性、磷酸单酯酶活性和植株磷吸收的影响。结果表明: 不同磷水平配施生物炭显著提高了两种土壤的速效磷和全磷含量,且低磷水平添加生物炭处理速效磷增幅最大,在赤红壤和褐土的增幅分别为192.6%和237.1%。与低磷相比,赤红壤中低磷配施生物炭处理的碱性磷酸单酯酶活性显著增加78.9%,活性有机磷含量降低39.3%,同时显著促进了植株生长与磷吸收;生物炭添加显著降低了褐土活性有机磷含量,但不同处理对土壤磷酸单酯酶活性和植株生长无显著影响。土壤活性有机磷含量与速效磷含量均呈显著负相关。综上,生物炭对土壤磷有效性的作用因土壤类型和磷肥水平差异而不同,其在赤红壤上对植株生长和磷吸收的促进效应强于褐土,且在低磷条件下效果更佳。本研究为生物炭在减施磷肥和促进大豆磷吸收,特别是在赤红壤上的应用提供了科学依据。