Response of winter wheat yield and soil microbial biomass to fertilization with ridge mulching-furrow planting in the dry highlands of the Loess Plateau北大核心CSCD

As the typical planting pattern of winter wheat in the dry highlands of the Loess Plateau, ridge mulching-furrow planting (RMFP) has played an important role in fertilizer efficiency of different fertilizers, and the differences in fertilizer efficiency further influence the diversity of the structure of soil microbial communities. The effects of different fertilization practices on winter wheat yield formation, soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), and soil microbial biomass phosphorus (SMBP) were investigated by field experiments during 2014-2016 in the winter wheat growing region of the dry highlands in southern Shanxi. The treatments included four groups, farmer fertilization (FF), monitoring fertilization (MF), monitoring fertilization combined application of manure (MFM), and monitoring fertilization combined application of bio-organic fertilizer (MFB). Results showed a significant increase in winter wheat yield by optimized and balanced fertilization, and the grain yield of MFB was highest among all treatments, with a value of 4 107-5 400 kg/hm2, which was 14.5%-23.2% (P < 0.05) higher than that of FF. The effects of different fertilization treatments on the winter wheat yield formulation mainly depended on spike number; however, no effect was found on kernel number per spike and 1 000-grain weight. Soil microbial biomass was affected by both growth period and fertilization patterns, i.e., the content of SMBC from jointing to flowering stage was highest during the winter wheat growth period, whereas the maximum values of SMBN and SMCP were found during the jointing stage. Changes in the rates of SMBC, SMBN, and SMBP during the entire growth period were less than 50%; however, the average contribution rate of optimized fertilization on SMBC, SMBN, and SMBP reached 90%. Compared to single chemical fertilizer applications, the combined application chemical fertilizer and manure or bio-organic fertilizer significantly improved the contents of SMBC, SMBN, and SMBP; however, the contents of SMBC and SMBN between MFM and MFB had no significant difference, whereas the SMBP of MFB was 19.8%-47.1% (P < 0.05) higher than that of MFM owing to the effect of mixed phosphorus bacteria. The soil microbial biomass C/N and C/P of the different treatments were 6.9-9.8 and 14.4-41.0, respectively, and maximum values occurred during the flowering stage. Given the above, the combined application of reasonable chemical fertilizer and bio-organic fertilizer can effectively improve the winter wheat yield and soil microbial biomass under RMFP cultivation in the dry highlands of the Loess Plateau. © 2018 Science Press. All rights reserved.     

西蒙得木对金沙江干热河谷生态保护的作用

金沙江干热河谷生态条件恶劣，水土流失严重，对长江流域中下游特别是三峡大坝存在着极大的负面影响。治理长江流域，保护三峡大坝的重要源头是金沙江干热河谷的生态环境建设。西蒙得木生长的生态环境与金沙江干热河谷的生态环境非常相似，并且西蒙得木具有极高的经济价值，因此在金沙江干热河谷种植西蒙得木，既能改良生态环境，又能发展当地经济。     

Hydrogen-rich synthesis gas production from waste wood via gasification and reforming technology for fuel cell application

The purpose of this study was to establish a fuel process for an advanced power generation system in which hydrogen-rich synthesis gas, as the fuel for the molten carbonate fuel cell (MCFC), can be extracted from biomass via gasification and reforming technologies. Experiments on waste wood gasification were performed using a bench-scale gasification system. The main factors influencing hydrogen generation in the noncatalytic process and in the catalytic process were investigated, and temperature was identified as the most important factor. At 950°C, without employing a catalyst, hydrogen-rich synthesis gas containing about 54 vol% hydrogen was extracted from feedstock with appropriately designed operation parameters for the steam/carbon ratio and the equivalence ratio. However, by employing a commercial steam reforming catalyst in the reforming process, similar results were obtained at 750°C.     

生物质废物热解过程中气相产物的生成及等离子体重整研究

针对松木屑的热解以及产物的等离子体重整进行研究。热解温度分别为400,500,600,700,800℃时,在加热30 min的条件下,主要气体产物是H2、CO、CH4和CO2,热解气的总生成量的摩尔分数由46.11%(400℃)增至80.12%(800℃)。介质阻挡放电等离子体重整结果显示,随着放电功率的增加,CH4和CO2的转化率以及H2/CO的摩尔比都呈现增长趋势,控制等离子体重整条件有助于获得高品位能源。     

水碳比变化对汽油氧化重整制氢影响的研究

本文用正辛烷代替汽油从理论和实验两方面研究了水碳比变化对汽油氧化重整制氢反应的影响。理论研究表明 ,在绝热反应条件下 ,对应确定的反应温度存在一个最佳的氧油比及水碳比 ;实验研究表明 ,在非绝热反应体系中 ,在一定的氧油比及反应温度条件下 ,反应体系的转化率及生成氢的选择性均随水碳比的增加而增加 ,为实现燃料电池汽油制氢自热反应 ,反应体系应在一定水碳比条件下进行 ,实验条件下最佳的水碳比范围是 1.5— 2 .5之间。     

软包装印刷的有机废气净化和溶剂回收工艺研究

为了促进企业开展节能减排和资源回用,在车间选取了一条干式复合线进行废气净化和溶剂回收及利用工艺研究,使用乙酸乙酯作为粘胶剂的稀释剂,废气净化和溶剂回收采用吸附浓缩+冷凝回收工艺,溶剂脱水提纯采用渗透汽化膜分离工艺.结果表明,这两种工艺组合十分适合干式复合线的溶剂回收和溶剂脱水提纯,处理装置具有溶剂回收率高、纯度好、运行...     

工业废气在循环流化床锅炉中的掺烧应用

介绍了东方化工厂两台循环流化床锅炉掺烧工业废气改造的背景及原则,叙述了火炬气回收及供气系统、燃气燃烧器、PLC控制三个主要系统的布置、选择、设计等情况,论述了锅炉掺烧火炬气后的安全、掺烧比例的确定、掺烧位置的选择等三个需要重点关注的问题,分析了项目实施后所取得的节能效益、环保效益,是同行业回收利用工业废气,实现节能降耗的一种有效方式,具有很好的参考价值和推广意义。     

不同量秸秆覆盖还田对土壤活性有机碳及碳库管理指数的影响

为探明渭北旱塬不同秸秆覆盖量对春玉米田土壤活性有机碳(LOC)、 碳库管理指数(CMI)和作物产量的影响,于2007—2010年在陕西合阳县旱农试验站进行定位试验,以不覆盖为对照(CK),设置了3个水平秸秆覆盖量处理:4 500 kg/hm²(S1)、 9 000 kg/hm²(S2)和13 500 kg/hm²(S3)。结果表明,0~20 cm土层,与CK相比,S1、 S2和S3总有机碳(TOC)质量分数分别提高5.08%、 14.12%和28.03%(P<0.05);活性有机碳(LOC)分别显著提高19.20%、 44.02%和23.50%(P<0.05);碳库管理指数(CMI)分别显著提高20.94%、 46.86%和50.21%(P<0.05)。春玉米产量分别与LOC和CMI显著相关(P<0.05),而与TOC则无显著相关性。研究表明,LOC和CMI较TOC更能灵敏、 客观地反映渭北旱塬不同量秸秆覆盖还田对土壤碳库质量的影响,且秸秆覆盖量以9 000 kg/hm²为宜。     

Water budget and the consequent duration of canopy carbon gain in a teak plantation in a dry tropical region: Analysis using a soil–plant–air continuum multilayer model

A soil–plant–air continuum multilayer model was used to numerically simulate canopy net assimilation (A_n), evapotranspiration (ET), and soil moisture in a deciduous teak plantation in a dry tropical climate of northern Thailand to examine the influence of soil drought on A_n. The timings of leaf flush and the end of the canopy duration period (CDP) were also investigated from the perspective of the temporal positive carbon gain. Two numerical experiments with different seasonal patterns of leaf area index (LAI) were carried out using above-canopy hydrometeorological data as input data. The first experiment involved seasonally varying LAI estimated based on time-series of radiative transmittance through the canopy, and the second experiment applied an annually constant LAI. The first simulation captured the measured seasonal changes in soil surface moisture; the simulated transpiration agreed with seasonal changes in heat pulse velocity, corresponding to the water use of individual trees, and the simulated A_n became slightly negative. However, in the second simulation, A_n became negative in the dry season because the decline in stomatal conductance due to severe soil drought limited the assimilation, and the simultaneous increase in leaf temperature increased dark respiration. Thus, these experiments revealed that the leaflessness in the dry season is reasonable for carbon gain and emphasized the unfavorable soil water status for carbon gain in the dry season. Examining the duration of positive A_n (DPA) in the second simulation showed that the start of the longest DPA (LDPA) in a year approached the timing of leaf flush in the teak plantation after the spring equinox. On the other hand, the end appeared earlier than that of all CDPs. This result is consistent with the sap flow stopping earlier than the complete leaf fall, implying that the carbon assimilation period ends before the completion of defoliation. The model sensitivity analysis in the second simulation suggests that a smaller LAI and slower maximum rate of carboxylation likely extend the LDPA because soil water from the surface to rooting depth is maintained longer at levels adequate for carbon gain by decreased canopy transpiration. The experiments also suggest that lower soil hydraulic conductivity and deeper rooting depth can postpone the end of the LDPA by increasing soil water retention and the soil water capacity, respectively.     

Book review

Environmental Management, (3 Volumes) Editors B. Nath, L. Hens and D. Devuyst (Brussels, Vubpress: 1993. Approx. 890 Pp. Paperback) (£25 Per Volume) Isbn 90 5487 035 4-6

The Chemistry and Deposition of Nitrogen Species in the Troposphere, Editor A. T. Cocks, Publisher Royal Society of Chemistry, 1993, X + 134pp., Isbn 0 85186 355 8, Price £35.00.