地表臭氧浓度增加对南京地区冬小麦生长和产量的影响   总被引：5，自引：0，他引：5  

刘宏举  郑有飞  吴荣军  赵泽  胡程达  石春红 《中国农业气象》2009,30(2):195-200

利用改进后的开顶式气室（OTC）,开展了O3浓度增加对冬小麦生长与产量影响的大田实验研究。实验设置三种处理：CK为未经处理的空气,CF100处理O3浓度为100nL／L,CF150处理O3浓度为150nL／L。结果表明,地表O3浓度增加,冬小麦生育期缩短,籽粒的灌浆期缩短,植株提前老化;同时,冬小麦的株高、生物量、叶面积等生长指标均显著下降（P〈0．05）,最大降幅分别达到了10．01％、36．56％和29．17％;冬小麦的穗数、穗粒数、单位面积产量等产量指标也都出现了显著下降（P〈0．05）,其中CF100、CF150处理的单位面积产量分别比CK下降了16．11％和39．17％。试验结果对于评估地表O3浓度增加对粮食安全的影响具有重要的指导意义。  相似文献   

土壤矿物吸附和土壤团聚体对土壤有机碳含量的影响研究   总被引：3，自引：1，他引：2  

WU Qing-Biao  WANG Xiao-Ke  OUYANG Zhi-Yun 《土壤圈》2009,19(2):258-264

Soil organic carbon (SOC) can act as a sink or source of atmospheric carbon dioxide; therefore, it is important to understand the amount and composition of SOC in terrestrial ecosystems, the spatial variation in SOC, and the underlying mechanisms that stabilize SOC. In this study, density fractionation and acid hydrolysis were used to assess the spatial variation in SOC, the heavy fraction of organic carbon (HFOC), and the resistant organic carbon (ROC) in soils of the southern Hulunbeier region, northeastern China, and to identify the major factors that contribute to this variation. The results showed that as the contents of clay and silt particles (0--50 μm) increased, both methylene blue (MB) adsorption by soil minerals and microaggregate contents increased in the 0--20 and 20--40 cm soil layers (P < 0.05). Although varying with vegetation types, SOC, HFOC, and ROC contents increased significantly with the content of clay and silt particles, MB adsorption by soil minerals, and microaggregate content (P < 0.05), suggesting that soil texture, the MB adsorption by soil minerals and microaggregate abundance might be important factors influencing the spatial heterogeneity of carbon contents in soils of the southern Hulunbeier region.  相似文献   

大孔隙对土壤水分入渗特性影响的物理模拟试验   总被引：8，自引：6，他引：2  

吴继强  张建丰  高瑞 《农业工程学报》2009,25(10):13-18

利用不同粒径砂石和大孔隙域模具模拟同一深度、不同有效面孔隙度,在特制试验装置中研究积水条件下大孔隙流的三维运移行为。结果表明：湿润峰平齐且稳定的转折时间和有效面孔隙度相关性较高;不同有效面孔隙度条件下累积入渗量符合Kostiakov模型但其参数是有效面孔隙度的函数;大孔隙的连通性在一定条件下对土壤水分的优先入渗起主导作用;大孔隙的存在导致大孔隙中心特征剖面湿润面积发生典型变化,给出了大孔隙中心特征剖面湿润面积增量的定量概念及其与有效面孔隙度之间的数学模型,并进行了验证,精度满足要求。  相似文献   

Energy balance and partition in Inner Mongolia steppe ecosystems with different land use types   总被引：3，自引：0，他引：3  

Shiping Chen  Jiquan Chen  Guanghui Lin  Wenli Zhang  Haixia Miao  Long Wei  Jianhui Huang  Xingguo Han 《Agricultural and Forest Meteorology》2009,149(11):1800

Land use change and grassland degradation are two of the most critical problems ubiquitously found in arid and semi-arid areas in Northern China. Energy fluxes, including net radiation (R_n), latent heat flux (LE), sensible heat flux (H) and soil heat flux (G), were examined over an entire year (December 2005 to November 2006) in different steppe ecosystems – the steppe and cropland in Duolun and the fenced and grazed steppe in Xilinhot – in Inner Mongolia based on direct measurements from four eddy-covariance flux towers. The seasonal changes in R_n, LE, H and G of the four sites were similar, with very low values during the period of snow cover from December to February, followed by a gradual increase in the growing season. The opposite seasonal patterns of the LE and H fraction resulted in significant seasonal changes in Bowen ratio (β). Human activity in cropland ecosystems not only resulted in a rapidly shift between LE and H, but also triggered a decrease in latent heat fraction because of a shortened growing season of crop plants. The significantly positive relationships between canopy surface conductance (g_c) and LE/LE_eq of all of the study sites suggested that a lack of precipitation coupled with high VPD conduced remarkable decreases of stomatal conductance. This could impede the latent heat partitioning of available energy (R_n − G) in semi-arid ecosystems, Inner Mongolia. The obvious decrease in the values of g_c and the decoupling factor (Ω) in both the cropland and the degraded steppe suggested that land use change could depress latent flux fraction and increase its sensitivity to air and soil drought.  相似文献   

黄河下游灌区农田排水再利用效应模拟评价   总被引：6，自引：2，他引：4  

许迪  丁昆仑  蔡林根  P S Minhas 《灌溉排水学报》2004,23(5):1-5

在田间试验观测基础上,采用SWAP模型分析黄河下游簸箕李引黄灌区农田排水再利用下的土壤盐分季节性变化以及地下水位对土壤盐分剖面分布的影响,模拟农田排水补灌对作物产量的效应。研究结果表明,咸排水补灌引起的土壤盐分积聚主要在冬小麦生长期,夏玉米生长期内并不明显,有效地控制地下水位有助于减少土壤盐分累积量,维系作物根区的盐分平衡。利用含盐量为4mg/cm3以下的农田排水在冬小麦生长后期水分亏缺阶段进行补灌,可在基本不影响随后夏玉米产量的基础上,不同程度地改善冬小麦产量。对缺水严重的黄河下游引黄灌区,农田排水再利用是缓解水资源供需矛盾、改善作物产量的一种有效水管理措施。  相似文献   

抗水牛伊氏锥虫变异表面糖蛋白抗原单克隆抗体的研制   总被引：1，自引：0，他引：1  

曾晓飞  陈汉忠  韦英益  何木荣  李晓栩 《中国畜牧兽医》2009,36(10):72-74

用纯化的伊氏锥虫变异表面糖蛋白（variant surface glucoprotein, VSG）免疫BALB/c小鼠,取免疫小鼠脾细胞与SP2/0骨髓瘤细胞进行融合,经过3次克隆和间接ELISA方法筛选,获得3D7、5B9 2株稳定分泌单克隆抗体的杂交瘤细胞株,用间接ELISA方法检测杂交瘤细胞培养液上清效价和小鼠腹水效价,其中细胞培养上清效价分别为1∶6400和1∶12800,腹水效价分别为1∶105和1∶106。单抗的亚型鉴定结果表明,3D7、5B9分泌的抗体都为IgG1亚类κ链。  相似文献   

Organic‐carbon fractions in an agricultural topsoil assessed by the determination of the soil mineral surface area     

Jean‐Marie Séquaris  Gregorio Guisado  Maria Magarinos  Carlos Moreno  Peter Burauel  Hans‐Dieter Narres  Harry Vereecken 《植物养料与土壤学杂志》2010,173(5):699-705

According to recent conceptual models, the organic carbon (OC) of soils can be divided into OC fractions of increasing stability from labile free OC to resistant OC associated with the soil mineral phase. In this study, we present a method for quantifying two OC fractions based on soil aggregate–size fractionation and the N₂ gas–adsorption method. For this purpose, we analyzed soil material of the plow layer of a Haplic Chernozem subjected to different fertilizer treatments (no fertilizer, mineral fertilizer, mineral and organic fertilizer). The total organic‐C concentration (TOC) and the clay content of the different size fractions were determined as well as the specific surface area (SSA_mineral) and the sample pore volume after thermal oxidation (OC‐free). The TOC of the different soil‐aggregate fractions was linearly related to SSA_mineral. Clay‐associated OC and nonassociated OC fractions of the different soil samples were quantified using two methods based on the OC surface loading at the clay fraction. The application of organic fertilizer increased the amount of nonassociated OC but hardly affected the concentration of clay‐associated OC. This finding agrees with previous studies on C dynamics in soils and indicates a finite capacity of soil materials to sequester OC. Even without any addition of organic fertilizer, the mineral phase of the analyzed soil material appears to be C‐saturated.  相似文献   

水稻秸秆用量对淹水培养土壤表层溶液理化性质的影响   总被引：3，自引：1，他引：2  

戴志刚  鲁剑巍  鲁明星  杨文兵  范先鹏 《中国生态农业学报》2010,18(1):20-24

采用模拟培养的方法,研究水稻秸秆用量对淹水培养土壤表层溶液理化性质的影响。试验根据秸秆还田量设0g·盆-1、100g·盆-1、200g·盆-1和300g·盆-14个处理,每盆装土15kg,施尿素2.8g以调节系统碳氮比,分别测定培养液的电导率、pH、全氮、全磷、全钾等指标。研究结果表明,各处理表层溶液电导率在培养初期呈上升趋势,第36d达到最大值,分别为960μs·cm-1、1150μs·cm-1、1467μs·cm-1和1620μs·cm-1,随后略有降低,到培养结束时分别为683μs·cm-1、910μs·cm-1、1083μs·cm-1和1277μs·cm-1。pH值在培养的前3d呈缓慢下降趋势,与秸秆用量呈负相关;从第4d开始pH迅速升高,16d后达到相对稳定状态,到培养结束时变化不大。施加的尿素导致各处理培养液中全氮在20d内保持较高浓度,随后全氮浓度迅速下降,到第76d,下降趋势减缓;施加秸秆对全氮浓度影响较小,施加秸秆能够提高全磷含量。秸秆中钾释放迅速,培养1d后,溶液全钾含量达到较高浓度,分别为6.87mg·L-1、36.10mg·L-1、60.27mg·L-1、114.23mg·L-1,在整个培养期全钾浓度变化不大。淹水培养条件下施加秸秆能够增加培养液中电导率、全磷及全钾浓度,与秸秆用量呈正比,但对pH、全氮影响较小。从养分流失角度考虑,控制田面养分流失主要时期为水稻秸秆还田后30d内。  相似文献   

实施科教文主导战略服务北京新农村建设   总被引：4，自引：0，他引：4  

王有年 《北京农学院学报》2006,21(1):1-6

建设社会主义新农村是我国现代化进程中的重大历史任务,是我党在新的历史条件下审时度势的战略部署。笔者以“实施科教文主导战略”为突破口,提出了科学谋划社会主义新农村建设的方法,总结出新农村建设是破解“三农”问题的总抓手,讨论了推进新农村建设应注意处理好的关系,以及现阶段推进京郊新农村建设的工作重点;总结了北京农学院服务新农村建设的成果,并为进一步服务京郊新农村建设提出了建议。  相似文献   

药液表面张力与喷雾方法对雾滴在水稻植株上沉积的影响   总被引：10，自引：0，他引：10  

徐德进  顾中言  徐广春  许小龙  范鹏 《中国水稻科学》2011,25(2):213-218

 以生物染料丽春红-G为示踪剂,采用比色法分析了药液表面张力及喷雾方法对雾滴在水稻植株上沉积的影响。结果表明,分蘖期、孕穗期、扬花期水稻叶片的临界表面张力值分别为34.46、34.36和34.33 mN/m。与喷洒清水对照相比,3个水稻生育期内喷洒添加有100 mg/L TX-10的丽春红-G溶液,单株水稻上的丽春红-G沉积率均有不同程度的增加,其中,手动喷雾器压顶喷雾分别增加了80.85%、29.80%和22.61%;弥雾机喷头下倾喷雾分别增加了50.83%、18.48%和31.07%。在相同的水稻生育期,喷洒相同表面张力的药液,弥雾机喷头下倾喷雾单株水稻上的丽春红-G沉积率均显著高于弥雾机漂移喷雾和手动喷雾器压顶喷雾。在稻田喷雾中,利用表面活性剂降低药液表面张力和采用弥雾机施药有助于提高雾滴在水稻植株上的沉积率。  相似文献