【作者】 贾宏涛；

【导师】 王益权；

【作者基本信息】 西北农林科技大学 ， 土壤学， 2004， 硕士

【摘要】 本试验是在典型干旱区—新疆三工河流域（草地生态系统选择在巴音布鲁克草原）进行的，主要依托中国科学院新疆生态地理研究所阜康荒漠生态试验站，以干旱区典型陆地生态系统为研究对象，对干旱区典型陆地生态系统 CO2源汇关系进行了系统研究，并对三工河流域及巴音布鲁克亚高山草地生态系统进行了碳估算，为评价不同生态系统的环境效应提供理论依据。取得了如下主要结论：1. 绿洲农田生态系统 各种类型的绿洲农田生态系统对的 CO2固定量有一定日变化差异，在夜间的 11 个小时内，各农田生态系统都是碳源，即净释放 CO2。而白天小麦生态系统和棉花生态系统都有 1 个小时为碳源。研究表明玉米农田生态系统对 CO2的净固定能力最强，24 小时固定 CO238.47g/m2。其次是小麦生态系统和棉花生态系统。从年固碳量来看，绿洲玉米生态系统为最高，达到 141.66 t CO2/hm2·a；其次为小麦生态系统，为 122.60 tCO2/hm2·a；棉花生态系统最低，为 50.39 t CO2/hm2·a。2. 荒漠林地生态系统 在夜间的 11 个小时内，各林地生态系统都是碳源，即净释放 CO2。而在白天，云杉林地生态系统有 7 个小时为碳源，研究表明：云杉林地生态系统对 CO2的净固定能力最弱，24 小时内净释放 CO2 4.22g/m2。最强的是梭梭林地生态系统，24 小时净固定CO218.34 g/m2。红柳林地生态系统对 CO2 的固定能力稍弱于梭梭林地生态系统。从各观测样地的年固碳能力来看，梭梭林地生态系统固定量最大达到了 9.29 t CO2/hm2·a，红柳林地生态系统次之，为 2.68 t CO2/hm2·a。云杉林地生态系统总体来看是一个弱的碳源，年释放量达到 8.20 t CO2/hm2，这与传统的观点相左，尚需要进一步研究。3. 亚高山草地生态系统 围栏封育条件下，草地生态系统日 CO2净固定量达到了 12.76gCO2/m2·d，每天除18 时和 21 时是弱的碳源外，其余时间均是碳汇。其中 16 时以前是碳的强汇，对 CO2的净固定量达到 12.02gCO2/m2，占到日总 CO2净固定量的 94.20%；自然放牧条件下，草地生态系统日 CO2净固定量达到了 11.52gCO2/m2·d，除 9 时、13 时、14 时和 21 时是弱的碳源外，其余时间均是碳汇。其中 15～19 时是碳的强汇，对 CO2的净固定量达到 9.46gCO2/m2，占到日 CO2净固定量的 82.00%。13、14 时出现弱源的主要原因是由于植物的光合速率在中午有所下降即“午休”现象导致的。每年的 5~9 月份是牧草的生长期，对巴音布鲁克亚高山草地生态系统 CO2的年固定量的初步估算结果表明：其 CO2固定量达到 7.14 t CO2/hm2·a。4. 碳估算<WP=6>4.1 三工河流域土壤碳估算 新疆三工河流域总碳储量约为 11.18Pg，其中有机碳约为 5.43 Pg，占 48.54%，无机碳约为 5.75Pg，占 51.46%。 各土壤生态系统相比较，森林土壤、草甸土壤具有较大的有机碳通量和有机碳容量，但其无机碳通量和无机碳容量均明显低于其它土壤生态系统；荒漠土壤生态系统的有机碳通量、碳容量最低，但其具有较高的无机碳储量。4.2 巴音布鲁克亚高山草地生态系统碳估算 巴音布鲁克亚高山草地生态系统地上植物体碳总量约为 7.20 万 t。其中地上部分约为 3.20 万 t，约占 44.44%；地下部分根系约为 4.0 万 t，约占到 55.56%。 对巴音布鲁克亚高山草原生态系统的土壤有机碳进行了估算，结果表明：亚高山草原生态系统土壤有机碳的平均碳通量为 16.80Ckg/m2，土壤有机碳总贮藏量约为 3019.22万 t。5. 土壤条件对凋落物分解速率的影响 壤质土上的有机物料分解速率高于粘质土和砂质土；中等土壤湿度条件下有机物料的分解速率最高；深埋方式有机物料的分解速率高于浅埋方式；中等土壤盐分条件下，有机物料的分解速率最高；不同类型凋落物，在其它条件完全相同的条件下，分解速率也不完全相同，主要是由于其木质素含量有所差异所致。本研究是在固定了其它因子的条件下，仅对单因子逐项进行了研究，因子间的交互作用尚需要进一步研究。更多还原

【Abstract】 The experiment was conducted in the typical terrestrial ecosystem in arid region ----Sangong River drainage area in Xinjiang (and the selected grassland ecosystem is atBayinbuluke Grassland) with Fukang Desert Ecology Experimental Station of XinjiangEcological Geography Academic Institution of Chinese Academy of Sciences as the mainbacking, typical terrestrial ecosystem in arid region as the subject investigated. CO2source/sink relation of typical terrestrial ecosystem in arid region is studied systematicallybased on field-study data in the field, and carbon concerning Sangong River drainage area andBayinbuluke subalpine meadow ecosystem is estimated. The main conclusions are as follows:1. Oasis field ecosystem There are certain differences among the fixation quantity of CO2 of different types offield ecosystems. All field ecosystems are carbon source, i.e. net discharge of CO2 during the11 hours at night. However, there is one hour acting as carbon source for wheat-soilecosystem and cotton-soil ecosystem in the daytime. Study shows that maize-soil ecosystemhas biggest capability of CO2 net fixation with fixation quantity of 38.47g/m2 per hour. Andwheat-soil ecosystem and cotton-soil ecosystem stand second on the list. From the point ofview of annual carbon fixation quantity oasis maize-soil ecosystem is highest up to 141.66 tCO2 /hm2.a; the following one is wheat-soil ecosystem with 122.60 t CO2 /hm2.a; andcotton-soil ecosystem is lowest with 50.39 t CO2 /hm2.a.2. Desert forestland ecosystem All forestland ecosystems are carbon source, i.e. net discharge of CO2 during the 11hours at night. However, there is 7 hours acting as carbon source for Picea schrenkianaforestland ecosystem. Study shows that Picea schrenkiana forestland ecosystem has theweakest capability of CO2 net fixation with net discharge of 4.22g/m2 within 24 hours. AndHaloxylon ammodendron forestland ecosystem is of the strongest capability with CO2 netfixation of 18.34g/m2 within 24 hours. The CO2 fixation capability of Tamarix ramosissimaforestland ecosystem is slightly weaker than that of Haloxylon ammodendron forestlandecosystem. From the point of view of annual carbon fixation quantity of each observed plot,Haloxylon ammodendron forestland ecosystem is highest up to 9.29 t CO2 /hm2.a; thefollowing one is Tamarix ramosissima forestland ecosystem with 2.68 t CO2 /hm2.a; AndPicea schrenkiana forestland ecosystem is a weak carbon source as a whole with annualdischarge quantity of 8.20 t CO2 /hm2.a which is at variance with traditional opinion andfurther study is needed.3. Subapline meadow ecosystem Under the condition of animal raising shut with fencing, the daily net fixation of CO2 ofgrassland ecosystem is 12.76gCO2 /m2.d, it is a carbon sink during the day except at 18:00and 21:00 during which it is a weak source and of the rest time of the day it is an obviousstrong carbon sink before 16:00 with CO2 net fixation of 12.02g CO2/m2 which occupies94.20% of daily total CO2 net fixation. Under the natural pasturing condition, the daily netfixation of CO2 of grassland ecosystem is 11.52gCO2 /m2.d, it is a carbon sink during the dayexcept at 9:00, 13:00, 14:00 and 21:00 during which it is a weak source and from 15:00 to19:00 it is an obvious strong carbon sink with CO2 net fixation of 9.46gCO2/m2 whichoccupies 82.00% of daily total CO2 net fixation. The main reason why a weak source appearsat 13:00 and 14:00 is that photosynthesis rate of vegetation declines a little at noon, i.e. theso-called noon break. The period from May to September every year is growing period offorage grass, for which the annual CO2 fixation of Bayinbuluke Subapline meadow ecosystem<WP=8>is up to 7.14 t CO2 /hm2.a according to the preliminary estimate.4. Estimation of carbon4.1 Estimation of carbon in Sangong River drainage area Total reserves of carbon in Sangong River drainage area, Xinjiang is estimated to beabout 11.18Pg, of which organic carbon is about 5.43Pg whic更多还原