覆盖及堆积高度对肉牛粪便温室气体排放的影响

为了研究覆盖对不同堆积高度肉牛固体粪便温室气体（N2O、CH4和 CO2）排放量的影响,试验采用静态箱的方法研究了20和40 cm堆积高度时覆盖或者不覆盖情况下肉牛粪便温室气体的排放量。结果表明,堆积40 cm的牛粪CH4的累积排放量显著高于20 cm处理,而N2O和CO2累积排放量显著降低。覆盖显著增加了牛粪N2O的排放量和40 cm高度牛粪的CH4排放量,降低了40 cm高度牛粪CO2的排放量,而对20 cm高度牛粪CH4和CO2排放无显著影响。根据CH4和N2O在100 a 尺度上相对CO2的全球增温潜势计算出综合温室效应,无覆盖处理的20和40 cm牛粪的综合温室效应分别为(101.07±6.28）和(94.67±3.29)g/kg,覆盖处理的20和40 cm牛粪的综合温室效应分别为(104.20±6.78)和(103.43±3.21)g/kg,堆积高度为40 cm且无覆盖的综合温室效应最小。     

表面风速和模拟降水对奶牛粪便堆放过程中N2O排放的影响

奶牛场粪便的自然堆放过程中会造成大量的温室气体排放,排放过程和排放量受表面风速和自然降水等环境因素的影响显著。该文针对中国常用的奶牛粪便管理方式,采用动态箱法研究了不同表面风速(0.5、0.8、1.2、1.6 m/s)和模拟降水(降水量9.9 mm)对奶牛粪便自然堆放过程中典型的温室气体氧化亚氮(N2O)排放的影响。结果表明,在0.5~1.2 m/s风速范围内,奶牛粪便自然堆放过程中的N2O排放量随风速升高逐渐增加,1.2 m/s达到最大值,且不同风速下N2O的排放量存在显著差异。模拟降水后N2O排放量在短时间内急剧升高,之后迅速下降至降水前的排放水平,整个过程持续约10 h。由于降低了二氧化碳(CO2)和甲烷(CH4)的排放,与降水前一天相比2次降水分别降低了12.9%和10.9%的温室气体排放量。     

堆积肉牛粪便甲烷排放影响因子试验

通过测定肉牛粪便在不同温度和堆高时的甲烷排放量,探讨了中国肉牛粪便甲烷排放量及其主要影响因素。采用动态箱法测定了肉牛粪便在15℃、25℃和35℃中,堆高分别为10cm、20cm和40cm时的甲烷排放通量,同时分析了试验前后粪便的性质。结果表明,15℃时肉牛粪便堆放15d的鲜牛粪甲烷排放通量为(0.031±0.002)～(0.002±0.000)g/(d·kg),累积排放量为0.17～0.18g/kg;25℃中堆放26d的甲烷排放通量为(0.323±0.018)～(0.051±0.063)g/(d·kg),累积排放量为3.8～5.1g/kg;35℃中堆放26d的甲烷排放通量为(0.414±0.073)～(0.033±0.050)g/(d·kg),累积排放量为3.6～6.6g/kg。15℃中粪便甲烷排放量显著小于25℃和35℃中的排放量(P<0.01)。粪便堆高与单位表面积的累积甲烷排放量相应也高。     

水稻根系生物特性与稻田温室气体排放相关性研究

通过湖南双季稻区温室气体排放差异的水稻品种田间试验,研究了不同品种温室气体排放与根系特征的相关性。结果表明,早稻分蘖盛期CH4排放通量与根干重、伤流量均呈显著负相关（P〈0.05）;晚稻CH4排放通量与根伤流量呈极显著负相关（P〈0.01）;早稻N2O排放通量在分蘖盛期与根伤流量相关性极显著（P〈0.01）,在齐穗期与根体积、干重、根伤流量均呈极显著负相关（P〈0.01）;晚稻分蘖盛期,根系干重与体积均与N2O排放通量呈显著正相关（P〈0.05）;齐穗期,根系体积与N2O排放通量呈显著负相关（P〈0.05）;早稻分蘖盛期CO2排放通量与根系干重和根伤流量呈显著正相关关系（P〈0.05）,晚稻齐穗期根系伤流量与CO2排放通量负相关性达到极显著水平（P〈0.01）。因此,根系特性是影响水稻温室气体排放的重要因素。     

夏季猪场污水贮存过程中CO2、CH4排放试验

猪场粪污是重要的温室气体排放源,针对中国缺乏猪场污水贮存过程中温室气体排放参数的问题,该文选择温度较高的夏季,利用动态箱法于2007年6月对猪场的三格式化粪池进行了CO2、CH4气体排放测试.测试结果表明:当大气平均温度为28.4℃时,86%的温室气体排放源于一级和二级化粪池,一级、二级和三级化粪池的温室气体排放通量分别为407.5、383.0、127.7 g/(m2·h)二氧化碳当量;CH4是本污水贮存单元中产生的主要的温室气体,一、二、三级化粪池排放的温室气体总量中,CH4排放的贡献率分别为95%、96%、95%,控制一、二级化粪池甲烷排放将大幅度减少猪场污水温室气体排放.     

翻耕对冬闲农田CH4和CO2排放通量的影响初探

通过连续观测，比较了冬闲农田翻耕和不翻耕情况下甲烷(CH4)和二氧化碳(CO2)的排放通量。结果表明：翻耕能显著增加CO2的排放通量，但这种影响只在翻耕后的4d内较明显；翻耕对CH4排放通量的影响在翻耕后的3d内比较明显，表现为翻耕初期导致CH4的峰值排放，而在6～8h后，则对降低CH4的排放有一定的作用。且CH4和CO2排放通量与气温呈显著正相关。     

覆盖材料和厚度对堆存牛粪氨气和温室气体排放的影响

为了研究锯末和稻草2种材料覆盖以及不同厚度的锯末覆盖对牛粪堆存过程中氨气(NH3)和温室气体(N2O、CH4和CO2)排放量的影响,采用静态箱的方法测试了不同覆盖厚度(1、3和5 cm)和2种材料(锯末和稻草)覆盖下牛粪NH3、N2O、CH4和CO2排放量。结果表明,在不同厚度锯末覆盖的试验中,与不覆盖处理组相比,覆盖降低了牛粪NH3和CO2累积排放量,但覆盖显著增加了牛粪N2O和CH4累积排放量(P0.05);3个覆盖处理组内,NH3、N2O和CO2排放量随着覆盖厚度的增加而下降,然而,CH4排放量随着覆盖厚度的增加而升高;1、3和5 cm厚锯末覆盖的牛粪总温室气体排放量分别为108.61、103.57和101.36 g/kg,与1 cm锯末覆盖相比,3和5 cm厚锯末覆盖的牛粪总温室气体排放量显著降低(P0.05)。在相同质量的锯末(2 cm厚)和稻草(6 cm厚)2种材料覆盖的比较试验中,2种材料覆盖都显著降低了牛粪NH3和CO2的累积排放量(P0.05),但同时也显著增加了CH4的累积排放量(P0.05);锯末覆盖增加了牛粪N2O累积排放量(P0.05),而稻草覆盖则降低了牛粪N2O累积排放量(P0.05)。与锯末覆盖相比,稻草覆盖显著增加了CH4的累积排放量(P0.05),但同时显著降低了牛粪CO2的累积排放量(P0.05);锯末覆盖和稻草覆盖牛粪总温室气体排放量分别为101.51和109.46 g/kg,与锯末覆盖相比,稻草覆盖显著增加了牛粪总的温室气体排放量。试验结果表明,较厚的锯末(3和5 cm)覆盖对牛粪NH3和温室气体的减排效果更好。     

不同秸秆还田年限对稻麦轮作系统温室气体排放的影响

为揭示稻麦轮作系统不同秸秆还田年限下温室气体排放特征及减排调控机制,本研究采用大田小区试验,考察了稻麦轮作不同秸秆还田年限[空白对照(CK)、常规处理秸秆不还田(NT)、1年秸秆还田(SR1)和5年秸秆还田(SR5)]对CH4、CO2和N2O 3种温室气体排放规律的影响,同时测定了土壤固碳量,估算了秸秆焚烧产生的温室气体排放量,综合计算了4种处理对全球变暖的贡献。试验结果表明,SR1和SR5均显著提升CH4和CO2的排放通量,分别高出NT、CK处理73.52%、309.49%和13.29%、13.06%;同时显著降低N2O排放通量,较NT降低29.68%和42.55%;但SR1和SR5之间温室气体排放通量差异不显著;与NT相比,SR1和SR5可以显著提高土壤固碳量517.9%和709.03%,SR5土壤固碳量高出SR1达30.93%;NT秸秆焚烧产生的全球气温变暖贡献为9 698.49 kg(CO2-eqv)·hm?2,比CK高126.98%。综合分析温室气体排放、土壤固碳以及秸秆焚烧3个因素,SR1全球升温贡献最低,显著低于NT 4.72%。短期全量秸秆还田有助于降低总体温室气体排放,长期进行秸秆还田后降低幅度会逐步减小。     

冬季猪舍粪便贮存过程中CO2排放特征

利用丹麦猪舍和液态猪粪便进行了CO2气体排放测试,比较了3种粪坑内粪便高度（0.15,0.40和0.65 m）、3种通风量（211,650和1 852 m3/h）、粪坑内有无挡板下冬季猪舍粪便贮存过程中CO2排放通量。测试结果表明：通风量、粪便温度和粪坑挡板可以用来解释大部分的CO2排放通量变化的差异;对于使用渗透性天花板进气和负压通风排气,CO2排放通量随着舍内通风量的增加而增大,3种通风量之间CO2排放通量差异显著;使用粪坑挡板可以显著降低粪坑内的空气交换和减少CO2排放通量;粪便贮存高度的变化对CO2排放通量的作用不明显;敏感性分析表明CO2排放通量相对于粪便温度的敏感性（敏感度值大）要高于通风量,在较低的通风量变化区间,CO2排放通量变化的敏感性要高于较高的通风量变化区间,但对于粪便温度变化趋势正好相反。通风量的增加同时会降低舍内和粪坑内空气温度以及粪便温度,因此要综合考虑通风量和温度对气体排放通量的影响。     

团头鲂池塘养殖生态系统晒塘阶段温室气体排放通量分析

为探讨团头鲂池塘养殖生态系统晒塘阶段温室气体的排放规律及综合增温潜势,采用静态暗箱——气相色谱法对团头鲂池塘养殖生态系统晒塘阶段温室气体(CO2,CH4,N2O)的排放进行原位测定。结果显示,团头鲂池塘养殖生态系统晒塘阶段均表现为CO2,CH4和N2O的排放源,其中CO2排放通量达(86.72±12.46)g/m2,CH4排放量达(2.01±0.34)g/m2,N2O排放量达(7.44±0.98)mg/m2;在100 a的时间尺度上,团头鲂池塘养殖生态系统在晒塘阶段综合增温潜势为(157.28±24.31)g/m2,团头鲂池塘养殖生态系统温室气体减排空间较大。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.