北京养殖鸡舍发酵床废弃垫料资源化利用评价

发酵床养殖技术是基于控制畜禽粪便排放与污染而发展起来的一种新型养殖技术。通过对不同养殖场发酵床废弃垫料理化性质进行测定,判断其是否能够直接作为有机肥料施用到土壤中。结果表明,废弃垫料中富含有机质、全氮、全磷、全钾等营养元素。其中有机质43.19%~53.95%,全氮2.28%~2.66%,全磷(P2O5)2.36%~2.70%,全钾(K2O)2.80%~3.62%,均符合国家有机肥料农业行业标准(NY 525—2012)。但废弃垫料中p H值为8.03~8.93,EC为3 679~4 310μS/cm,大肠杆菌数量在48.00×104~52.00×104cfu/g之间,沙门氏菌数量在18.33×102~38.33×102cfu/g之间,种子发芽率指数为15.88%~31.52%。在废弃垫料资源化利用方面,发酵床废弃垫料虽具有有机肥料的基本性质,但是其p H值偏碱性,盐分含量偏高,存在使我国北方土壤碱化、土壤盐渍化风险;大肠杆菌严重超标,具有生物安全隐患;种子发芽率指数低,说明废弃垫料中存在抑制种子萌发的毒素。因此施用前必须对养殖发酵床废弃垫料进行无害化处理。     

养猪舍不同发酵床垫料重金属Zn累积特征初探

为了研究养猪舍不同发酵床垫料及发酵床底部表层土壤中重金属Zn的累积特征与活性大小,以节约经济成本和适宜猪生长发育为前提选取3种发酵床垫料组合:FJ(40%稻壳+60%菌糠)、FD(40%稻壳+60%锯木屑)、FW(40%稻壳+60%酒糟),采用物质流分析(MFA)和潜在生态危害评价的方法进行研究。结果表明,一个在养猪周期过后,重金属Zn在垫料FD中累积量较大;而不同垫料对Zn活性大小的影响不同,FD中有效态Zn活性显著高于其他2种,所占比例高达25.01%,其次是FJFW(P0.05);表层土壤中,有效态Zn活性高低差异不显著(P0.05)。所选取的3种垫料中,尽管Zn在FJ中累积量最小,渗漏到土壤中的全量Zn与有效态活性与其他2种垫料无明显差异,然而其潜在生态风险最小,因此从控制Zn污染角度出发,该配比垫料优于FD与FW。经过潜在生态危害评价分析,3种垫料在养殖结束后其潜在生态危害均未超过轻微生态危害临界值(Ei r≤40),在不断补充垫料的前提下发酵床可以使用约10年。     

发酵床养猪废弃垫料的资源化利用评价

发酵床养殖技术是基于控制畜禽粪尿排放与污染的一种新型生态养殖模式,但其有机废弃物的处理和应用值得进一步研究.本文测定了我国山东、吉林两省5个发酵床养猪场的废弃垫料的有机质、氮、磷、钾、重金属元素、抗生素和盐分含量以及有害微生物数量.结果表明,废弃垫料中富含有机质、氮、磷、钾等营养元素.其中有机质含量为42.62％～54.12％,全氮1.54％～2.12％,全磷(P2O5)2.24％～5.55％,全钾(K2O)0.57％～2.15％;Cu、Zn、Cr、As、Ni、Pb、Cd、Hg等8种重金属元素含量均符合国家有机肥料农业行业标准(NY 525-2012)和城镇垃圾农用控制标准(GB 8172-1987)的限量标准;土霉素(Oxytetracycline,OTC)、四环素(Tetracycline,TC)、金霉素(Chlortetracycline,CTC)等四环素类抗生素含量低,环境风险小;蛔虫卵和大肠杆菌含量均超过NY 525-2012和GB 8172-1987的规定限值,蛔虫卵死亡率范围为90％～94％,总大肠杆菌的数量范围为1.29×105～2.24×106cfus/g;垫料盐分含量达到22.11～45.71g/kg.评价结论:发酵床废弃垫料具有有机肥料的基本性质,但是盐分含量偏高;肠道寄生虫卵严重超标,具有生物安全隐患,施用前必须对其进行无害化处理.     

猪发酵床不同垫料中As、Hg累积规律

为研究在发酵床养猪过程中不同组成垫料的As、Hg累积规律,本文以木屑、稻壳和秸秆为原料,配制成3种垫料处理,分别为木屑(S)、木屑+稻壳(SR)和木屑+稻壳+秸秆段(SRS),在一年半的时间里,测定了4批育肥猪养殖结束时不同层次垫料中As、Hg含量,分析了长期使用后不同发酵床垫料中As、Hg累积情况,为发酵床废弃垫料的后续农用提供理论依据。结果表明,随着猪养殖批次的延长,3种处理及其不同层次垫料As、Hg含量均存在不同程度增加。4批猪养殖结束时,As累积量最大的是SRS处理的发酵床,为1 921.7 mg·栏~(-1),Hg累积量最大的也是SRS处理的发酵床,为21.1 mg·栏~(-1)。S、SR、SRS处理的As、Hg含量分别为2.921、2.190、2.621 mg·kg~(-1)和0.048、0.036、0.042 mg·kg~(-1),均符合《农业行业标准有机肥料》(NY 525—2012)、《食用农产品产地环境质量评价标准》(HJ/T 332—2006)的标准限值。     

养猪发酵床不同发酵程度垫料微生物群落结构特征的PLFA分析

发酵床养猪是一种新型的养殖技术,可有效缓解养猪的环境污染问题,微生物在其中起关键作用。为明确养猪发酵床发酵过程微生物群落的变化规律,为发酵床的科学管理提供依据,本研究采用磷脂脂肪酸生物标记（phospholipid fatty acids,PLFA）法分析养猪发酵床不同发酵等级垫料的微生物群落结构特征。采用色差法将垫料分为3个发酵程度等级：1级、2级和3级,采集不同发酵等级表层（0~15 cm）和里层（30~45 cm）垫料样本,测定各样本的PLFA。结果表明,共检测到61种PLFA,发酵2级垫料的PLFA种类最多,发酵3级垫料的PLFA种类最少。在各垫料中,PLFA分布量均表现为细菌 > 真菌 > 放线菌。指示细菌、真菌、放线菌、革兰氏阳性细菌（G⁺）、革兰氏阴性细菌（G^-）的PLFA及总PLFA在各发酵等级表层垫料的分布量均显著大于其在里层垫料的分布量,最大值出现在发酵1级表层垫料中。与对照（未发酵垫料）相比,发酵垫料总PLFA含量均显著增加（P<0.05）。发酵3级表层垫料的真菌/细菌值最大,发酵2级表层垫料的G⁺/G^-值最大。多样性分析表明,Shannon指数和Pielou指数最大值出现在发酵2级垫料中,而Simpson指数最大值出现在发酵3级表层垫料中。聚类分析表明,当欧氏距离为233.15时,可将不同发酵等级垫料聚为3个类群,同一发酵级别的垫料聚在相同类群中;主成分分析表明,发酵1级表层和里层垫料单独归一类群,其他发酵等级垫料和对照垫料归另一类群中。综上,不同发酵等级垫料的微生物种群结构不同,发酵1级表层垫料微生物分布量最大,发酵2级垫料的微生物种类最多,相同发酵级别表层和里层垫料微生物群落结构相似。     

养猪发酵床垫料有机肥对辣椒产量及土壤微生物多样性的影响

随着环保压力的日益增加和农户环保意识的逐渐增强,发酵床养猪技术逐渐被农户接受,但是发酵床熟化垫料再利用相对较难,限制了发酵床养猪技术的推广。本研究将两种发酵床熟化垫料分别进行高温堆肥处理,熟化垫料总养分(氮、磷、钾)含量均超过50 g/kg,重金属和粪大肠杆菌含量均未超标,蛔虫卵死亡率95%以上,符合商品有机肥标准。作物试验表明,在等氮量施用条件下,发酵床熟化垫料有机肥施用后辣椒产量与化肥和常规有机肥处理相当,并能提高辣椒品质,改善土壤肥力。PCR-DGGE结果表明,不同处理土壤细菌群落结构可大致分为3种类型,对照(CK)和化肥(CF)处理群落结构相似,为第一类;常规猪粪有机肥(POF)为第二类;两种发酵床熟化垫料有机肥(FOF和ROF)群落结构相似,为第三类。施肥处理能明显改变土壤微生物多样性,施用有机肥(POF、FOF、ROF)对土壤微生物多样性改变的效果比化肥(CF)大;不同来源的有机肥(POF和FOF、ROF)对土壤中微生物区系改变方向不一样,来源接近的有机肥(FOF和ROF)对土壤微生物区系改变方向接近。     

养猪发酵床垫料微生物及其猪细菌性病原群落动态的研究

微生物发酵床养猪是一种新型环保养殖技术。开展了微生物发酵床垫料微生物及其猪细菌性病原群落动态的研究,通过分离不同使用时间和层次基质垫层中的细菌、真菌和放线菌,分析微生物发酵床垫料微生物群落动态;分离基质垫料中大肠杆菌和沙门氏菌,研究其在发酵床垫料中的时间、空间分布动态,分析微生物发酵床对这两种病原细菌的抑制效果。结果表明,微生物发酵床中细菌分布数量最大,在各使用时间和层次的分布量均达到10~7 cfu·g~(-1)数量级以上,放线菌分布数量次之,真菌分布数量最小;细菌的分布数量呈现随着垫料使用时间的增加先上升后下降的趋势,而真菌和放线菌分布量随着垫料使用时间的增加而减少。基质垫料有一定量大肠杆菌和沙门氏菌的分布,分布数量与细菌呈显著的负相关,与真菌和放线菌呈显著正相关,在垫料使用的后期(使用5个月)比使用前期(使用1个月)分布数量明显减少,减少幅度分别为95.34%和44.41%,说明微生物发酵床对猪舍大肠杆菌和沙门氏菌病原能起到显著的抑制作用,控制由大肠杆菌和沙门氏菌病原引起的猪病害。     

棉隆消毒改善发酵床垫料基质连茬栽培西瓜的效果研究

以发酵床垫料为主要原料的复合基质作为栽培基质,采用槽式栽培方式,研究连茬种植西瓜效果、种后基质理化和微生物学性状的变化特征以及棉隆消毒后旧基质连茬种植西瓜效果。结果表明:种完1茬西瓜的旧基质继续种植西瓜会出现再植障碍,整个生育期枯萎病发病率可达35%;种植西瓜对基质中尖孢镰刀菌数量影响显著,连续种植2茬西瓜后,基质中尖孢镰刀菌数量可从0升高至8.0×10~3cfu·g~(-1)基质;种完1茬西瓜的旧基质经棉隆消毒处理后,真菌和尖孢镰刀菌数量均显著减少,且继续种植西瓜后其产量和单果重与新配基质相比均无显著差异。     

养猪微生物发酵床真菌空间分布特性研究

微生物发酵床养猪是一种新型环保的养殖方式,发酵床中的微生物在分解消纳、去污除臭方面发挥着重要的作用。为了解大栏养猪微生物发酵床的真菌空间分布特性,通过空间格局采样、分离鉴定发酵床中的真菌并统计其在不同空间的种类与含量;利用空间分布频次、空间分布型指数、多样性指数和生态位特征等指标,评估发酵床真菌种群的空间分布特性,为养猪发酵床管理、猪粪资源化利用、猪病防控等提供理论依据。结果表明:从32个空间样本中共分离鉴定出真菌18个种,归于10个属,其中种最多的是曲霉属,包含7个种。发酵床不同空间样本的真菌种与数量存在明显差异,种数为1~4,数量为4×102~5.8×105菌落数·g-1。高频次分布的种有总状毛霉和橘青霉,分布频次大于10次;高数量分布的种有短柄帚霉、构巢曲霉和亮白曲霉,大于2.00×105菌落数·g-1。利用6个空间分布型指数和Taylor幂法则的分析结果表明:发酵床的真菌种群呈聚集分布型。32个空间样本种群多样性指数分析结果表明:除两个空间样本仅分离到1个种类外,其他30个空间样本呈现明显的空间分布多样性,为集聚分布和不均匀分布。空间样本2-A和3-D真菌种群具有较高的丰富度、均匀度和优势度,包含出现频次和数量较高种类,如总状毛霉、尖孢枝孢菌、橘青霉和构巢曲霉。空间样本1-A和1-B的真菌数量最大、种类也较多,但它们的丰富度、均匀度和优势度均较低,所包含的多为出现频次低于3次的种类,如亮白曲霉、短柄帚霉和白地霉。生态位特征的分析表明:发酵床中真菌的生态位宽度与生态位重叠没有明显的正相关性。总状毛霉和尖孢枝孢菌生态宽度值大,分别为7.60和5.18,为广适应种;而亮白曲霉、薛氏曲霉、土曲霉、短柄帚霉、水贼镰刀菌和毛壳属菌等6个种的生态位宽度值较小,仅介于1.00~1.10,为窄适应种。总状毛霉可与其他12个种存在重叠,但尖孢枝孢菌仅与其他2个种存在重叠。总之,养猪微生物发酵床的真菌种群呈现明显的群落多样性,空间分布特性为聚集分布和不均匀分布,总状毛霉和尖孢枝孢菌为优势种群,在发酵床中分布广、适应性强。     

层叠式笼养肉鸭舍冬季环境测试及通风窗位置优化模拟

肉鸭产业规模化程度越来越高、空间集聚日益明显,层叠式笼养是发展最为迅速的立体养殖模式。该文对层叠式笼养鸭舍内的温湿度、气流、CO_2及NH_3质量浓度进行测试,构建了鸭舍的CFD模型,开展温度场和气流场的环境模拟,并提出现有鸭舍气流组织形式的优化方案。研究结果表明,测试期间(2018-12-18 00:00-2018-12-22 00:00),鸭舍内气温11.35～20.68℃,舍内外平均温差10.86℃;舍内平均相对湿度70.27%,略高于舍外;舍内CO_2、NH_3平均质量浓度分别为3285、0.33 mg/m~3。模拟原有鸭舍的温度场和气流场,与实测结果进行对比,平均相对误差为6.59%～8.87%,说明该文所建模型的数值模拟与试验数据具有很好的一致性。进一步通过降低一侧通风小窗的高度来优化鸭舍的气流组织,模拟发现优化后模型的舍内温度范围为11.07～19.71℃,其温度波动范围较原模型有明显减小,降低了肉鸭对温度的应激效应;优化后模型北侧第1列底层、第3列中层、第5列上层的平均风速分别为0.34、0.34、0.31 m/s,较原模型更加均匀。通过该研究,可为同类型鸭舍合理规划设计与改善舍内环境质量提供理论依据。     

半阶梯式笼养蛋种鸡舍冬季日间空气污染物排放特征

蛋鸡舍空气颗粒物、空气微生物和氨气等污染物的排放不但影响场区生物安全,更会造成环境污染问题。该文采用直线多点均匀采样新型系统,对北京地区某半阶梯式笼养蛋种鸡舍冬季空气颗粒物、微生物和氨气3种污染物的日间排放进行监测和分析,研究半阶梯式笼养蛋种鸡舍冬季日间空气污染物排放特征。结果表明,该蛋种鸡舍试验期间舍内温度保持在18.0~20.0℃;间歇性通风条件下,风机的开启时长和舍外温度具有正相关关系(P0.05,R2=0.883 7);在冬季8:00-18:00期间,空气颗粒物的排放质量浓度为0.5~0.8 mg/m~3,每只鸡排放量为1.0~1.5 mg/h;空气微生物的排放浓度为4.0~4.5 log10CFU/m~3,每只鸡排放量为4.3~4.8 log10 CFU/h;氨气排放浓度为7.6~14.3 mg/m~3,每只鸡排放量为8.1~13.7 mg/h。试验期间,舍外温度低于舍内温度,试验鸡舍通风量及波动范围小,空气颗粒物、空气微生物和氨气的排放浓度、排放量与舍外温度、通风量、舍内相对湿度之间均未发现相关关系(P0.05)。该研究结果可为中国蛋鸡舍空气污染物排放特征提供参考。     

Chemical Attributes of Soil and Forage Yield of Pasture Recovered with Phosphate Fertilization and Soil Management

Extensive and semi-extensive pastures are the basis of Brazilian livestock production. However, much of it is degraded or in degradation process, with low stocking rate per area. Even with this problem, this management type is 60% and 50% of Australia’s and the United States’ production costs, respectively. In order to research alternatives for Urochloa decumbens degraded pasture recovery in an Oxisol, Stylosanthes (Stylosanthes spp.) “Campo Grande” cultivar was introduced and phosphate fertilization was applied. The experimental design was of randomized blocks, 7 × 2 × 2 factorial design, with four replicates, involving seven systems to introduction (U. decumbens control; partial desiccation with 1.5 L ha^?1 glyphosate, total desiccation with 3.0 L ha^?1 glyphosate; direct planting; scarification, harrowing, and plowing + harrowing), phosphate fertilizer presence or absence, and two evaluation periods. “Campo Grande” Stylosanthes legume introduction increased shoot dry weight (SDW) yield, except in direct planting. Phosphorus fertilization increased SDW yield only in the first period, and Stylosanthes introduction in the pasture has not changed soil chemical properties. Phosphorus (P) fertilization also provided available P and exchangeable calcium (Ca²⁺) content in the soil increase, in addition to sum of bases and cation exchange capacity increase.     

Assessment of Bacterial and Fungal Aerosol in Different Residential Settings

The concentration and size distribution of bacterial and fungal aerosol was studied in 15 houses. The houses were categorized into three types, based on occupant density and number of rooms: single room in shared accommodation (type I), single bedroom flat in three storey buildings (type II) and two or three bedroomed houses (type III). Sampling was undertaken with an Anderson six-stage impactor during the summer of 2007 in the living rooms of all the residential settings. The maximum mean geometric concentration of bacterial (5,036 CFU/m³, ± 2.5, n?=?5) and fungal (2,124 CFU/m³, ± 1.38, n?=?5) aerosol were in housing type III. The minimum levels of indoor culturable bacteria (1,557 CFU/m³, ±1.5, n?=?5) and fungal (925 CFU/m³, ±2.9, n?=?5) spores were observed in housing type I. The differences in terms of total bacterial and fungal concentration were less obvious between housing types I and II as compared to type III. With reference to size distribution, the dominant stages for culturable bacteria in housing types I, II and III were stage 3 (3.3–4.7 μm), stage 1 (7 μm and above) and stage 5 (1.1–2.1 μm), respectively. Whereas the maximum numbers of culturable fungal spores were recovered from stage 2 (4.7–7 µm), in housing type I, and from stage 4 (2.1–3.3 μm) in both type II and III houses. The average geometric mean diameter of bacterial aerosol was largest in type I (4.7 μm), followed by type II (3.89 μm) and III (1.96 μm). Similarly, for fungal spores, type I houses had the highest average mean geometric diameter (4.5 μm), while in types II and III the mean geometric diameter was 3.57 and 3.92 μm, respectively. The results indicate a wide variation in total concentration and size of bioaerosols among different residential settings. The observed differences in the size distributions and concentrations reflect their variable airborne behaviour and, as a result, different risks of respiratory exposure of the occupants to bioaerosols in various residential settings.     

提高鸭蛋清洁度的层叠式笼养蛋鸭笼底网的优化设计

为解决层叠式蛋鸭笼养设备在笼养鸭过程中出现鸭蛋表面脏污严重的问题,该文优化设计了蛋鸭笼底网外形尺寸参数。该文建立鸭蛋滚落运动仿真模型,利用二分法确定笼底网坡度合理范围。基于笼底网坡度合理范围,综合考虑笼底网间距、笼底网直径、笼底网质量及最大位移变形,建立笼底网优化数学模型。以有限元软件ANSYS为计算平台,采用三因素四水平相应曲面分析法,并基于最大位移变形响应面对蛋鸭笼底网尺寸参数进行寻优,寻优结果中笼底篦漏孔最大的一组解为最优解。优化结果较优化前,笼底网坡度增大至8.5°,笼底篦漏孔增大29.2%,笼底网最大位移变形量下降18.1%;为进一步检验优化结果可行性,该文利用优化后笼底网进行蛋鸭笼养试验。试验结果显示,蛋鸭笼底网优化后显著提高了鸭蛋清洁度,对毛羽品相、产蛋率及鸭蛋破损率无显著影响。该研究可为禽类笼养设备笼网的研制提供参考。     

Quantitation of mule duck in goose foie gras using TaqMan real-time Polymerase Chain Reaction

A real-time quantitative Polymerase Chain Reaction (PCR) method has been developed for the quantitation of mule duck (Anas platyrhynchos x Cairina moschata) in binary duck/goose foie gras mixtures. The method combines the use of real-time PCR with duck-specific and endogenous control "duck + goose" primers to measure duck content and total foie gras content, respectively. Both PCR systems (duck-specific and duck + goose) were designed on the mitochondrial 12S ribosomal RNA gene (rRNA). The duck-specific system amplifies a 96 bp fragment from duck DNA, whereas the duck + goose system amplifies a 120 bp fragment from duck and goose DNA. The method measures PCR product accumulation through a FAM-labeled fluorogenic probe (TaqMan). The C(t) (threshold cycle) values obtained from the duck + goose system are used to normalize the ones obtained from the duck-specific system. Analysis of experimental duck/goose foie gras binary mixtures demonstrated the suitability of the assay for the detection and quantitation of duck in the range of 1-25%. This genetic marker can be very useful to avoid mislabeling or fraudulent species substitution of goose by duck in foie gras.     

Response of oat-triticale mixture to post-emergence weed harrowing

ABSTRACT

In experiments with weed harrowing crops are negatively affected by competing weeds but also by the destructive effect of used implement. This research was carried out to find growth stages during which mixture of oat (Avena sativa L.) and triticale (× Triticosecale Wittm.) was resistant to harrowing and was able to effectively recover from this physical disturbance. Plots were harrowed 1–3 times on the same day at six consecutive stages of mixture growth with spring-tine harrow. After the latest harrowing, all plots were sprayed with herbicide to exclude competitive effect of weeds on the mixture. Compared to non-harrowed plots plant density of mixture was significantly reduced after a single cultivation at 1- and 2-leaf stage (20% and 23% respectively), two cultivations at 3-leaf stage (22%) and three at the beginning of the tillering (21%). No yield penalty was noticed for the density reductions, thus showing high ability of mixture to recover from physical disturbance. We recommend plant emergence as an appropriate growth stage for single harrowing of oat-triticale mixture. Two cultivations on the same day should not be planned earlier than at the beginning of tillering.     

平养蛋鸭种蛋智能收集和标记系统设计与试验

目前平养蛋鸭只能采用家系选育法而不能采用个体选育法,这是因为在平养条件下很难实现蛋鸭与所产蛋的准确对应.蛋鸭家系选育法的主要缺点是复杂,劳动强度大,准确度低,严重影响选种的精度和效率.在平养环境下实现蛋鸭个体选育法的关键在于找到一种智能化无应激的精确识别和标记蛋鸭个体与其所产种蛋的方法.该文以蛋鸭为研究对象,提出了一种新型的平养蛋鸭种蛋智能收集和标记系统设计框架,给出了上位机和下位机的组网拓扑图和逻辑控制算法.该系统采用射频技术和光电传感器技术融合,实现了蛋鸭产蛋个体的准确识别,识别正确率为100%.利用非接触式喷码打印技术将蛋鸭个体编号信息记录在其所产种蛋蛋壳上,解决了蛋鸭个体与所产鸭蛋对应关系的无应激自动记录难题.设计并实现了集种蛋收集和标记于一体的新型集蛋装置.该装置由集蛋区、调整区和喷印区3部分组成.集蛋区采用梯形凹槽结构和EVA海绵弹性触面设计,消除了种蛋在加速滚落过程中积累的动能,种蛋的破损率低于1%.调整区采用滑触式种蛋姿态导向设计,种蛋姿态调整的合格率达到了99.80%,保证了蛋壳长轴截面作为喷印面,使喷印的字符最大程度保持完整性.喷印区采用连续式油墨喷码机完成蛋鸭个体与种蛋对应关系的标记,喷码标识清晰可读合格率为98.2%.该研究可为蛋鸭生产过程中个体产蛋行为分析和种蛋信息的自动收集提供参考.     

黑龙江省大庆地区植被和土壤碳氮储量的最新估算

利用1978年MSS多光谱数据、2008年中国资源卫星数据和野外实验数据,对黑龙江省土壤退化典型地区大庆地区的植被和土壤碳氮储量进行了估算。结果表明:大庆地区的植被平均碳密度1978年为0.58 kgm-2,2008年为0.67 kgm-2;土壤平均碳氮密度分别为(8.18±1.65)kgm-3和(0.37±0.11)kgm-3,土地覆被平均土壤碳氮密度分别为(7.53±2.16)kgm-3和(0.33±0.16)kgm-3。1978和2008年植被碳储量分别为9.38×106 t和1.04×107 t,30年期间植被碳储量增加了1.02×106 t;全区土壤总碳量为(1.65±0.33)×108 t,总氮量为(7.55±2.15)×106 t;全区土地覆被土壤总碳量为(1.52±0.44)×108 t,总氮量为(6.74±3.32)×106t。大庆地区的植被和土壤平均碳密度都低于中国的平均水平,应加强土地保护,防止土壤的进一步退化。     

Verification of traffic-induced soil compaction after long-term ploughing and 10 years minimum tillage on clay loam soil in South-East Norway

Grain yields are presented from a 10-year field trial with four tillage regimes (annual ploughing, harrowing only, ploughing/harrowing alternate years and minimum tillage) on clay loam. We also present soil physical analyses and use the compaction verification tool (CVT) to assess compaction on plots with annual ploughing and minimum tillage, after using slurry tankers with contrasting wheel loads (4.1 Mg, 6.6 Mg) and wheeling intensities (1×/10×) in the 11th trial year, and yields monitored two years after compaction. Winter wheat yields in the period before compaction were strongly affected by tillage, with annual ploughing giving on average 24% higher yield than direct drilling. Both wheat and oats were far less affected in treatments with harrowing only or ploughing/harrowing alternate years, on average within 6% of annual ploughing. Yields after compaction were affected by both previous tillage and compaction intensity. In the first year, single wheeling after annual ploughing gave 23% yield reduction with 4.1 Mg wheel load and 28% reduction with 6.6 Mg wheel load, whilst multiple wheeling gave 14% reduction at 6.6 Mg wheel load. Yield reductions after minimum tillage ranged from 63% (single wheeling with 4.1 Mg) to 100% (multiple wheeling with 6.6 Mg). Similar trends were found in the second year. The soil physical data indicated that all wheeling led to changes in bulk density, pore sizes and permeability in both topsoil and subsoil on both sampled tillage plots. However, effects in the subsoil were partly masked by the soil's high initial bulk density, partly due to its high clay content. The CVT, which plots air capacity against hydraulic conductivity, suggested some harmful compaction on both plots, with the minimum tillage plot being less affected than the ploughed plot. However, yield results did not support this conclusion, indicating that other factors limited yields on the minimum tilled plot.     

京津冀秸秆养分资源及秸秆焚烧气体污染物排放定量估算

为推动区域农作物秸秆综合利用,减少秸秆露天焚烧气体对环境的影响,以京津冀地区为研究对象,评估分析了各类农作物秸秆资源产生、利用状况及其应用潜力,并定量估算了该地区主要农作物秸秆露天焚烧气体污染物排放特征。结果表明,2012年京津冀地区农作物秸秆资源总产量为5 406.9万t,秸秆中氮、磷、钾养分资源总量分别达到3.7×10~4、7.4×10~4、1.0×10~6 t。秸秆资源化利用方式主要以还田为主,北京市、天津市、河北省还田量分别占秸秆量的67.7%、27.3%和61.2%。秸秆露天焚烧主要以小麦和玉米秸秆为主,占田间秸秆焚烧总量的93.03%,焚烧排放的污染物总量分别达到1.0×10~6和4.8×10~5 t。基于京津冀地区秸秆利用现状,建议因地制宜地推动秸秆全量化利用,并在秸秆还田机制、离田利用机制、组织管理机制、技术研发机制等方面出台系统配套的政策措施,以期为中国不同区域秸秆资源的科学利用提供参考。