秸秆带状覆盖对土壤有机碳及其活性组分的影响

为了探讨秸秆带状覆盖对旱地不同剖面深度土壤总有机碳(TOC)、可溶性有机碳(DOC)、微生物量碳(MBC)和易氧化态碳(EOC)的影响,于2017—2020年在甘肃省布设秸秆带状覆盖试验,设玉米整秆带状覆盖(TSM)处理,以黑膜双垄沟全膜覆盖(TPM)和传统露地平作(TNM)为对照.结果表明:土壤有机碳和活性碳组分含量...     

长期秸秆还田对褐土农田土壤有机碳、氮组分及玉米产量的影响

基于1992—2022年连续30 a的长期定位试验,研究秸秆不还田（CK）、秸秆覆盖还田（SM）、秸秆粉碎直接还田（SC）和秸秆过腹还田（CM）4种不同秸秆还田方式对土壤有机碳、氮组分和作物产量的影响。结果表明：（1）不同秸秆还田方式均可增加耕层土壤有机碳、全氮及其组分含量;与CK相比,CM处理0~20 cm土层土壤的总有机碳（SOC）、轻组有机碳（LFOC）、微生物量碳（MBC）、水溶性有机碳（DOC）和颗粒有机碳（POC）的含量分别显著增加42.85%、93.51%、80.09%、190.42%和123.38%;土壤全氮（TN）、轻组有机氮（LFON）、微生物量氮（MBN）、水溶性有机氮（WSON）和颗粒有机氮（PON）的含量分别显著增加49.37%、34.26%、69.49%、172.73%和129.29%。（2）各活性有机碳组分与土壤有机碳的比值表现为LFOC>POC>MBC>DOC;各氮组分与土壤全氮的比值表现为LFON>PON>MBN>WSON。（3）CM和SC处理下敏感指数最高的指标为DOC,DOC可作为CM和SC处理早期有机物变化的指示物;SM处理下敏感指数最高的指标为LFOC,LFOC可作为SM处理早期有机物变化的指示物。（4）土壤有机碳、氮组分间均呈显著正相关关系,其中DOC可以较好地反映SOC的变化情况,WSON可较好地反映TN的变化情况。（5）与CK相比,长期秸秆还田均可以显著提高玉米产量,SM、SC和CM处理30 a累计产量分别增加6.38%、7.82%和23.00%。综上,长期秸秆还田是提高土壤有机碳氮组分含量和作物产量的有效耕作措施,以秸秆过腹还田效果最为突出,可在黄土高原旱地玉米种植区域推广。     

外源铅在土壤中的年际变化及对土壤有机碳矿化和速效养分的影响

以关中土为供试土样进行田间试验,向耕层土壤中添加不同浓度外源铅(Pb0:背景值,CK;Pb1:175 mg·kg~(-1)+背景值;Pb2:350 mg·kg~(-1)+背景值),进行小麦—玉米轮作试验。分别于2011—2013年小麦收获季采集耕层(0~20 cm)土壤,分析土壤中铅全量及有效态铅含量的年际变化,以及铅对小麦-玉米轮作模式下土壤有机碳(SOC)、溶解性有机碳(DOC)、微生物量碳(MBC)、碱解氮、速效磷、速效钾含量的影响。结果表明,三年中,施铅处理下土壤中铅全量及有效态铅含量分别下降13.22%和30.65%,总体呈现逐年下降趋势。与对照(CK)相比,Pb1、Pb2处理下SOC平均含量分别下降了16.30%和11.86%;DOC平均含量分别下降了4.05%和7.34%,与土壤铅含量呈现显著负相关关系;低浓度铅污染下土壤微生物商(q M)显著高于对照土壤,微生物量碳含量变化不显著。此外,土壤速效养分的分析显示,土壤碱解氮含量在外源铅加入初期下降明显,且在Pb1处理下碱解氮减少量最大;土壤速效磷含量随土壤铅含量增加而呈现下降趋势;土壤速效钾含量则随土壤铅含量的增加而增加。试验表明,外源铅的加入影响了土壤有机碳的稳定性,对土壤碳、氮循环产生了一定的影响;能够与土壤溶液中的磷酸根生成难溶性盐,与土壤胶体或土壤矿物晶格中的K+发生置换,加大土壤速效养分的流失风险。     

The fate of fertilizer N applied to cotton in relation to irrigation methods and N dosage in arid area

Quantitative information on the fate and efficiency of nitrogen (N) fertilizer applied to coarse textured calcareous soils in arid farming systems is scarce but, as systems intensify, is essential to support sustainable agronomic management decisions. A mesh house study was undertaken to trace the fate of N fertilizer applied to cotton (Gossypium hirsutum L. cv., Huiyuan701) growing on a reconstructed profile (0-100 cm) of a calcareous (>15% CaCO 3 ) sandy loam soil. Two irrigation methods (drip irrigation, DI; and furrow irrigation, FI) and four N application rates (0, 240, 360 and 480 kg/hm 2 , abbreviated as N 0 , N 240 , N 360 , and N 480 , respectively) were applied. 15 N-labelled urea fertilizer was applied in a split application. DI enhanced the biomass of whole plant and all parts of the plant, except for root; more fertilizer N was taken up and mostly stored in vegetative parts; N utilization efficiency (NUE) was significantly greater than in FI. N utilization efficiency (NUE) decreased from 52.59% in N 240 to 36.44% in N 480 . N residue in soil and plant N uptake increased with increased N dosage, but recovery rate decreased consistently both in DI and FI. Plant N uptake and soil N residue were greater in DI than in FI. N residue mainly stayed within 0-40 cm depth in DI but within 40-80 cm depth in FI. FI showed 17.89% of N leached out, but no N leaching occurred in DI. N recovery rate in the soil-plant system was 75.82% in DI, which was markedly greater than the 55.97% in FI. DI exhibited greater NUE, greater residual N in the soil profile and therefore greater N recovery rate than in FI; also, N distribution in soil profile shallowed in DI, resulting in a reduced risk of N leaching compared to FI; and enhanced shoot growth and reduced root growth in DI is beneficial for more economic yield formation. Compared to furrow irrigation, drip irrigation is an irrigation method where N movement favors the prevention of N from being lost in the plant-soil system and benefits a more efficient use of N.     

长期秸秆和地膜覆盖对旱作冬小麦农田土壤碳组分的影响

地表覆盖秸秆和地膜是我国西北旱作农田土壤固碳的重要田间管理措施,但其对土壤碳组分的长期影响尚不明确。基于田间定位试验,设生育期高量秸秆覆盖(9 000 kg·hm^-2,HSM)、生育期低量秸秆覆盖(4 500 kg·hm^-2,LSM)、夏闲期秸秆覆盖(9 000 kg·hm^-2,FSM)、生育期地膜覆盖(PM)和无覆盖对照(CK)共5个处理,研究了秸秆覆盖和地膜覆盖12 a和13 a后旱作冬小麦农田土壤总有机碳(SOC)、颗粒有机碳(POC)、潜在矿化碳(PCM)和微生物量碳(MBC)含量的变化规律。2 a平均结果表明：与CK相比,HSM和LSM处理均显著提高了0～10 cm土层各碳组分含量以及10～20 cm土层SOC、POC、MBC含量,同时还显著提高了0～20 cm土层POC和MBC占SOC的比例;而FSM和PM处理对各土层土壤碳组分含量及其占SOC的比例均无显著影响。土壤碳组分含量相互之间均存在极显著正相关关系。综上可知,长期生育期秸秆覆盖能有效提高旱作冬小麦农田耕层土壤有机碳及其组分含量,且提高覆盖量有助于促进...     

水分优化对温室葡萄产量及土壤生物学特性的影响

为揭示滴灌不同水分调控下设施栽培葡萄产量与土壤学特性等相关指标的响应关系,在甘肃省永登县设施葡萄试验基地开展葡萄滴灌不同生育期水分调控田间灌溉试验,分析水分调控对设施栽培葡萄土壤积温、蔗糖酶和淀粉酶活性、有机碳(TOC)、微生物量碳(MBC)和微生物熵(qMB)等土壤学特性的影响,基于隶属函数综合分析明确影响葡萄产量及各项土壤生物学特性指标的最佳水分优化处理。结果表明:新梢期水分胁迫的土壤积温、土壤酶、TOC、MBC、qMB均显著(P <0. 05)高于对照;新梢期水分胁迫较对照可增产44. 6%;果实膨大期作为葡萄生长的关键阶段,此时水分胁迫对土壤淀粉酶影响不显著,但对其他土壤学特性指标具有一定的抑制作用,并且可减产9.7%;隶属函数综合分析表明,土壤生物学特性指标及产量综合隶属排名为:PS﹥FS﹥CS﹥CK﹥ES。     

覆盖方式对旱作小麦田土壤团聚体有机碳的影响

依托中国科学院长武黄土高原农业生态实验站的长期覆盖试验,分析研究秸秆覆盖和地膜覆盖对黄土高原旱作冬小麦田土壤团聚体分布和团聚体有机碳的影响,共包括4种处理:无覆盖(CK)、全年9 000 kg·hm~(-2)秸秆覆盖(M_(9000))、全年4 500 kg·hm~(-2)秸秆覆盖(M_(4500))和全年地膜覆盖(PM)。结果表明:(1)与CK处理相比,M_(9000)处理土壤总有机碳含量提高8.1%(P0.05),M_(4500)和PM处理较CK处理无显著差异。(2)M_(9000)、M_(4500)处理0.25 mm团聚体含量较CK处理分别提高6.6%、4.1%,PM处理降低1.7%。(3)与CK处理相比,M_(9000)处理平均重量直径(MWD)值提高9.2%,PM处理降低14.8%;M_(9000)处理几何平均直径(GMD)提高13.0%,PM处理降低15.7%(P0.05)。(4)土壤总有机碳与0.25 mm团聚体含量、MWD和GMD值呈显著正相关。(5)各处理中,5 mm和0.25 mm团聚体中有机碳含量较高;M_(9000)处理可不同程度地提高各级别团聚体中有机碳的含量,PM处理作用不明显;土壤有机碳主要储存在机械稳定性大团聚体中,且5 mm团聚体对总有机碳的贡献率最大,M_(9000)、M_(4500)处理可提高0.25 mm团聚体有机碳的贡献率。(6)各处理土壤总有机碳与5 mm和0.25 mm机械稳定性团聚体中有机碳呈极显著正相关。因此,长期秸秆覆盖不仅可以提升团聚体水平和稳定性,还可增加团聚体中有机碳含量,有利于土壤有机碳的固定。该区全年9 000 kg·hm~(-2)秸秆覆盖处理效果最好。     

Decomposition characteristics of organic materials and their effects on labile and recalcitrant organic carbon fractions in a semi-arid soil under plastic mulch and drip irrigation

Labile organic carbon(LC) and recalcitrant organic carbon(RC) are two major fractions of soil organic carbon(SOC) and play a critical role in organic carbon turnover and sequestration. The aims of this study were to evaluate the variations of LC and RC in a semi-arid soil(Inner Mongolia, China) under plastic mulch and drip irrigation after the application of organic materials(OMs), and to explore the effects of OMs from various sources on LC and RC by probing the decomposition characteristics of OMs using in-situ nylon mesh bags burying method. The field experiment included seven treatments, i.e., chicken manure(CM), sheep manure(SM), mushroom residue(MR), maize straw(MS), fodder grass(FG), tree leaves(TL) and no OMs as a control(CK). Soil LC and RC were separated by Huygens D's method(particle size-density), and the average soil mass recovery rate and carbon recovery rate were above 95%, which indicated this method was suitable for carbon pools size analysis. The LC and RC contents significantly(P0.01) increased after the application of OMs. Moreover, LC and RC contents were 3.2%–8.6% and 5.0%–9.4% higher in 2016 than in 2015. The applications of CM and SM significantly increased(P0.01) LC content and LC/SOC ratio, whereas they were the lowest after the application of TL. However, SOC and RC contents were significantly higher(P0.01) after the applications of TL and MS. The correlation analysis indicated the decomposition rate of OMs was positively related with LC content and LC/SOC ratio. In addition, lignin, polyphenol, WOM(total water-soluble organic matter), WHA(water-soluble humic acid), HSL(humic-like substance) and HAL(humic acid-like) contents in initial OMs played important roles in SOC and RC. In-situ nylon mesh bags burying experiment indicated the decomposition rates of CM, SM and MS were significantly higher than those of MR, FG, and TL. Furthermore, MS could result in more lignin derivatives, WHA, and HAL polymers in shorter time during the decomposition process. In conclusion, the application of MS in the semi-arid soil under a long-term plastic mulch and drip irrigation condition could not only improve soil fertility, but also enhance soil carbon sequestration.     

不同耕作措施对麦—豆轮作条件下土壤有机碳库与微生物商的影响

以长期定位试验为基础,对麦-豆轮作次序下不同耕作措施间的土壤有机碳、易氧化碳以及微生物生物量碳进行了测定,计算了土壤微生物商在各个序列中变化并对土壤各级有机碳库进行了相关分析.结果表明:两种轮作次序下传统耕作结合秸秆还田、免耕不覆盖、免耕秸秆覆盖与传统耕作不覆盖相比更有利于土壤有机碳库含量的提高,同时各处理表层有机碳含量明显高于其它层次并且随着土层的增加而递减.相关分析结果显示,土壤活性有机碳较大程度上依赖土壤有机碳的含量,同时也说明易氧化碳与微生物都在一定程度上表征了土壤中活性较高部分的有机碳含量.不同耕作处理的土壤微生物商均表现为NTS、NT、TS处理大于T处理,和不同耕作处理下土壤总有机碳含量的变化趋势一致.相较于其它处理免耕秸秆覆盖的土壤微生物商在各个序列中变化最明显,说明免耕秸秆覆盖对土壤有机碳含量的增加和土壤有机质的累积的贡献最大.     

耕作方式对旱地麦田土壤团聚体及其碳氮组分分布的影响

为明确蓄水保墒耕作方式下旱地麦田土壤团聚体稳定性、有机碳及碳组分和全氮及氮组分在不同粒径团聚体组分中的分布特征,深入了解不同耕作方式下土壤碳氮固持机制,以连续3 a(2017—2020年)实施不同耕作方式(免耕、深松、深翻)后冬小麦收获期0～20 cm土壤为研究对象,采用湿筛法测算土壤团聚体的构成与稳定性(R_0.25,>0.25 mm团聚体含量;MWD,平均重量直径;GMD,几何平均直径),并测定各粒径团聚体有机碳(SOC)和碳组分(重组有机碳,HFOC;轻组有机碳,LFOC;易氧化有机碳,EOC;可溶性有机碳,DOC;颗粒有机碳,POC)含量、全氮(TN)和氮组分(硝态氮,NO^-₃-N;铵态氮,NH⁺₄-N;可溶性有机氮,SON)含量,分析了碳氮组分的相关关系。结果显示：(1)免耕和深松处理>2 mm团聚体土壤比例较深翻处理分别提高8.8%和22.1%,免耕有利于增加<0.053 mm粉黏粒比例,较深松和深翻处理分别提高46.4%和27.7%。深松处理较深翻...     

青海湖环湖区表土有机碳氮储量估算

分析了沿青海湖湖岸采集的81个表土样品的总有机碳和氮含量得出：环湖区表土有机碳储量为27.81×10^6t,总氮储量为30.24×10^5t。占研究区面积最大的栗钙土,其表层土壤有机碳密度（8.19kg/m^2）显著高于同类研究,氮含量（3.63mg/g）亦高于青海省同类土壤的平均值,说明环湖区表土碳氮储量都是相当大的...     

有机污染水灌溉对土壤有机碳状况的影响

以长期采用有机污染型水灌溉的陕西交口灌区的农田土壤作为研究对象,并以气候条件、土壤条件以及耕作制度基本一致,长期采用未污染的地下水灌溉的农田土壤作为对照,分别测定土壤剖面上总有机碳含量、有机碳组成等指标,结合第二次全国土壤普查资料,分析长期采用有机污染水灌溉对土壤有机碳累积速率及有机碳密度的影响,探讨关中土壤"环境碳容量"水平及提升土壤有机碳潜力的途径。结果表明:长期采用有机污染水灌溉,土壤有机碳主要在耕层(0~20 cm)极显著地增加,且增加部分主要是活性有机碳组分,其累积速率是对照灌区的近3倍,非活性有机碳处于相对平衡状态。土壤有机碳的剖面分布发生了明显的分化现象,活性有机碳的变化比总有机碳的变化更为显著。有机污染水灌溉的土壤有机碳密度显著高于对照土壤,尤其在0~40 cm范围内其差异达极显著水平。结果证实渭河水中富含的有机污染物提升了灌溉农田土壤有机碳贮量,关中地区农田土壤环境碳容量仍未达到饱和水平,通过外源有机碳的输入,仍然有增加土壤有机碳含量的可能。     

不同生育阶段咸水滴灌对红枣根区土壤有机碳垂直分布特性的影响

为探索咸水滴灌对红枣根区土壤有机碳含量的影响,采用大田咸水滴灌试验,在不同的灌水定额和咸水矿化度条件下,对红枣不同生育阶段根区土壤有机碳的影响进行分析。结果表明：不同矿化度的咸水滴灌处理后,不同生育阶段红枣根区土壤有机碳,随着土层深度的增加呈“S”形变化,影响土壤有机碳的咸水矿化度依次为：3 g/L＞4 g/L＞淡水对照＞2 g/L,表层10～30 cm的土壤有机碳含量较30～50 cm处高,而30～40 cm土层的有机碳含量相对最小。当矿化度一定时,影响红枣根区土壤有机碳含量的灌水定额依次为：30 L＞20 L＞10 L,说明在利用咸水灌溉时,适度增加灌水量是弱化盐分对土壤有机碳产生影响的有效途径。相对于其他处理,灌水定额为30 L,矿化度为2 g/L的咸水滴灌在促进枣树根系对土壤有机碳利用方面的影响最显著。     

Effects of Caragana microphylla plantations on organic carbon sequestration in total and labile soil organic carbon fractions in the Horqin Sandy Land,northern China

Afforestation is conducive to soil carbon(C) sequestration in semi-arid regions. However, little is known about the effects of afforestation on sequestrations of total and labile soil organic carbon(SOC) fractions in semi-arid sandy lands. In the present study, we examined the effects of Caragana microphylla Lam. plantations with different ages(12-and 25-year-old) on sequestrations of total SOC as well as labile SOC fractions such as light fraction organic carbon(LFOC) and microbial biomass carbon(MBC). The analyzed samples were taken from soil depths of 0–5 and 5–15 cm under two shrub-related scenarios: under shrubs and between shrubs with moving sand dunes as control sites in the Horqin Sandy Land of northern China. The results showed that the concentrations and storages of total SOC at soil depths of 0–5 and 5–15 cm were higher in 12-and 25-year-old C. microphylla plantations than in moving sand dunes(i.e., control sites), with the highest value observed under shrubs in 25-year-old C. microphylla plantations. Furthermore, the concentrations and storages of LFOC and MBC showed similar patterns with those of total SOC at the same soil depth. The 12-year-old C. microphylla plantations had higher percentages of LFOC concentration to SOC concentration and MBC concentration to SOC concentration than the 25-year-old C. microphylla plantations and moving sand dunes at both soil depths. A significant positive correlation existed among SOC, LFOC, and MBC, implying that restoring the total and labile SOC fractions is possible by afforestation with C. microphylla shrubs in the Horqin Sandy Land. At soil depth of 0–15 cm, the accumulation rate of total SOC under shrubs was higher in young C. microphylla plantations(18.53 g C/(m~2·a); 0–12 years) than in old C. microphylla plantations(16.24 g C/(m~2·a); 12–25 years), and the accumulation rates of LFOC and MBC under shrubs and between shrubs were also higher in young C. microphylla plantations than in old C. microphylla plantations. It can be concluded that the establishment of C. microphylla in the Horqin Sandy Land may be a good mitigation strategy for SOC sequestration in the surface soils.     

长期定位施肥对旱作农田土壤有机碳及其组分的影响

基于田间定位试验,研究了长期施肥对旱作冬小麦农田土壤有机碳及其组分的影响,试验包括4个处理:不施肥(CK)、氮磷配施(NP)、化肥与有机肥配施(NPM)以及长期休闲地(BL)。结果表明:长期持续施肥30年后,在0~30 cm土层,NPM处理土壤有机碳、微生物量碳、潜在矿化碳以及碳库管理指数分别较CK提高了42.2%、55.9%、40.9%和40.0%(P0.05),NP处理土壤有机碳和微生物量碳与CK差异不显著,潜在矿化碳和碳库管理指数分别提高了29.1%和20.0%(P0.05),施肥对两种活性有机碳含量的影响在15~30 cm土层表现更加显著;与种植作物相比,长期休闲显著降低了土壤潜在矿化碳含量,BL处理较CK降低了20.5%(P0.05)。相关性分析表明,土壤有机碳、潜在矿化碳、微生物量碳以及碳库管理指数两两之间存在着显著的相关性,且有机碳组分含量与土壤有机碳含量在处理间变化具有一致性(除NP处理外),两种活性有机碳相对含量在各处理间差异均不显著。总的来说,长期持续施入有机肥能够有效地增加旱作农田土壤有机碳同时增加其活性组分,有助于培肥地力和土壤固碳。     

盐渍化弃耕地不同恢复年限土壤有机碳及其碳库管理指数变化

对干旱区盐渍化弃耕地不同恢复年限土壤有机碳及其碳库管理指数的变化进行分析,结果表明,弃耕地恢复初期土壤有机碳及活性有机碳（LOC）含量均低于弃耕地（CK）,恢复3年（R3）、恢复5（R5）年和恢复10（R10）年的 LOC 都显著高于弃耕地,分别高出20．28％、16．00％和16．45％,土壤有机碳及活性有机碳含量均随着土层加深而降低,土壤碳库管理指数 CMI 在恢复初期低于 CK ,随着恢复年限的增加,R3,R5,R10土壤 CMI 显著高于CK 54．72％、19．79％和17．73％,R3、R5和 R10分别是 R1的3．20、2．48 和 2．43倍,表明干旱区盐渍化弃耕地经垦殖恢复后显著改善了土壤碳库质量,增加了土壤碳汇功能。相关分析表明,土壤 LOC 和 CMI 与土壤 Olsen－P 呈显著正相关关系,与 TOC 相比更能反映不同恢复年限土壤碳库的变化。     

Long-term effects of gravel―sand mulch on soil organic carbon and nitrogen in the Loess Plateau of northwestern China

Gravel–sand mulch has been used for centuries to conserve water in the Loess Plateau of northwestern China. In this study, we assessed the influence of long-term(1996–2012) gravel–sand mulching of cultivated soils on total organic carbon(TOC), light fraction organic carbon(LFOC), microbial biomass carbon(MBC), total organic nitrogen(TON), particulate organic carbon(POC), mineral-associated organic carbon(MOC), permanganate-oxidizable carbon(KMn O4-C), and non-KMn O4-C at 0–60 cm depths. Mulching durations were 7, 11 and 16 years, with a non-mulched control. Compared to the control, there was no significant and consistently positive effect of the mulch on TOC, POC, MOC, KMn O4-C and non-KMn O4-C before 11 years of mulching, and these organic C fractions generally decreased significantly by 16 years. LFOC, TON and MBC to at a 0–20 cm depth increased with increasing mulching duration until 11 years, and then these fractions decreased significantly between 11 and 16 years, reaching values comparable to or lower than those in the control. KMn O4-C was most strongly correlated with the labile soil C fractions. Our findings suggest that although gravel–sand mulch may conserve soil moisture, it may also lead to long-term decreases in labile soil organic C fractions and total organic N in the study area. The addition of manure or composted manure would be a good choice to reverse the soil deterioration that occurs after 11 years by increasing the inputs of organic matter.     

镰叶锦鸡儿湿地土壤酶活性分布特征及其与活性有机碳表征指数的关系

选取伊犁河谷昭苏县镰叶锦鸡儿湿地土壤为研究对象,研究其土壤酶活性(脲酶活性,蔗糖酶活性,过氧化氢酶活性)与土壤活性有机碳(土壤水溶性有机碳WSOC,土壤易氧化碳ROC,土壤微生物量碳MBC)的分布特征及其内在关系,分析镰叶锦鸡儿湿地土壤酶活性和土壤有机碳表征指数两者的相互关系。研究表明:镰叶锦鸡儿湿地的土壤酶活性随着土层深度的增加而下降;活性有机碳含量随土壤深度的增加,其垂直剖面的含量呈下降趋势。镰叶锦鸡儿湿地解放桥有锦鸡儿剖面的土壤酶活性和活性有机碳表征指数的含量均大于无锦鸡儿剖面,表明镰叶锦鸡儿在生长过程中可以提高土壤酶活性与活性有机碳含量;蔗糖酶,脲酶和过氧化氢酶与土壤活性有机碳呈极显著相关关系(P0.01),表明土壤酶对土壤活性有机碳的迁移转化起着重要作用。     

人工防护林对风沙土有机碳动力学的影响

选取塔里木沙漠公路沿线定植年限为5、7、10、13、16 a的防护林,运用物理化学提取法及傅里叶变换红外光谱仪,研究人工防护林对风沙土发育过程中土壤有机碳动力学的影响。结果表明:(1)随定植年限增加,土壤碳储量变化不大;(2)土壤有机碳在0~50 cm随深度增加而降低,50 cm以下变化不大;(3)随防护林定植年限的增加,表层土壤(0~10 cm)中总有机碳(TOC)、微团聚体有机碳(OCMIA)、腐殖质有机碳(OCHS)、抗氧化性(OCNa Cl O)和抗酸解性有机碳(OCHCl)均有所升高,其中TOC、OCMIA、OCHS逐年增加,而OCNa Cl O和OCHCl在5~7 a时增加较快,以后趋于稳定,且各碳组分(OCHCl除外)在不同定植年限防护林风沙土间的差异极显著(P0.01),OCHCl差异显著(0.01P0.05);(4)所有碳组分极显著相关,其中OCMIA、OCHS与TOC的相关性比OCHCl、OCNa Cl O高;(5)惰性碳库中OCMIA和OCNa Cl O占总有机碳的比例较高,OCHS相对含量随定植年限增加而升高;(6)腐殖质结构中C=O相对含量(C=O/C-O-C)先降低后升高,脂族链聚亚甲基碳含量占末端甲基碳的比例(CH2/CH3)7 a时最高,后3个年限变化不大。因此,人工防护林引起了土壤有机碳累积,特别是惰性碳库在表层累积,腐殖化程度增加,提高了土壤固碳能力并促进了风沙土的发育。     

短期N、P添加对荒漠草原土壤非保护性有机碳的影响

以干旱、半干旱地区荒漠草原土壤为研究对象,研究N、P养分添加对荒漠草原0～30 cm土层土壤颗粒有机碳和轻组有机碳含量、分配比例、敏感指数的影响,探讨荒漠草原土壤非保护性有机碳分配比例及其向保护性有机碳的转化速率对N、P添加的响应.研究结果表明:短期N、P添加能促进荒漠草原表层土壤(0～10 cm)土壤颗粒有机碳和轻组...