不同播期、烧堆措施和定期喷药在缅甸马铃薯晚疫病综合防治中的作用

调查在农民田和缅甸山州农业试验农场山区进行，根据病害测报评价定期用药、播期、烧堆措施在马铃薯晚疫病综合防治中的效果。试验1的结果表明，在未施药的不同播期小区晚疫病严重，而施达克尼尔的小区病情明显轻。在试验2中，Wallin‘s测报系统准确地预测马铃薯晚疫病的初发生期，并建议开始施药。降雨量12．7mm时施药比每周定期施药更有效。不同施药处理比不施药的对照增产30．1％－62．2％。病害造成的产量损失23．1％－38．3％。烧堆措施对防治晚疫病无效，不过可增产39．2％。     

“区域统筹、整体推进、终端扶持”是破解秸秆禁烧与全量利用的根本出路

秸秆焚烧是全社会高度关注的环境问题,文章分析了当前秸秆禁烧与综合利用工作存在的管理、政策及技术等问题,提出了“区域统筹、乡为基础、收还结合、政策引导、市场运行”的秸秆全面禁烧与全量利用工作思路,并指出在技术上应着重围绕“区域控制、收还统筹、突破收集、开拓用途、创新机制”开展攻关与集成创新。此外,分析了乡 (镇) 域尺度上实施“区域统筹与整体推进”秸秆全量利用策略的效果。在江苏省泗洪县车门乡的实践证明:采用区域统筹、整体推进的策略,可有效实现区域内秸秆全量利用与全面禁烧的目标。     

多年连续计划烧除对云南松林坡面水土流失的影响

为探讨多年连续计划烧除对云南松林坡面水土流失的影响,科学评价云南松林计划烧除后森林生态系统的服务功能,2019年在滇中新平县照壁山云南松林设置计划烧除区域和未烧除区域的径流小区,对降雨及产流产沙变化进行了定位观测,建立了降雨、径流和泥沙的数值关系,结果表明:(1)2019年研究区降雨量为568.6 mm,仅为多年平均降雨量939.79 mm的60.5%,降雨主要集中雨季5—10月,雨季降雨量占年降雨总量的73.8%。雨季降雨51场次,其中产流降雨28场,占雨季降雨总量的93.7%。(2)多年连续计划烧除增强了降雨转化为林地坡面径流的能力,且小雨量级最能凸显计划烧除促进林地坡面径流泥沙的产生。(3)计划烧除小区和未烧除小区的径流主要与降雨量显著相关,计划烧除小区的径流与降雨呈幂函数关系,未烧除小区的径流与降雨呈多项式关系。(4)计划烧除小区和未烧除小区的泥沙均与降雨量、径流量显著相关,且泥沙与降雨、径流的关系均呈幂函数形式。表明多年连续计划烧除改变林地水文特征,提高了降雨转化为林地坡面径流的能力,提高了径流挟带泥沙的能力,才使计划烧除林地的径流泥沙比未烧除林地多。     

An in-situ Technique for Producing Low-Cost Agricultural Biochar

Application of biochar to agricultural soils is effective to sequester atmospheric carbon and improve soil quality, but current pyrolysis and transportation costs are high, making biochar too costly to be used at the field scale. This study developed a new in-situ technique, burning and soil covering(B-SC), which can be used by farmers for production of biochar with crop residue. In this study,the air-dried feedstocks, elephant grass and corn residue, were burnt in situ for biochar production in the field. After approximately 90% of the leaves were combusted, the burning process was dramatically slowed down by covering the feedstock with soil. The biochar yield averaged 18.0 ± 1.3(n = 15) and 13.7 ± 1.3(n = 10) kg per 100 kg air-dried feedstock for the elephant grass and corn residue,respectively. The biochar properties were suitable for soil improvement. The inputs for biochar production of the B-SC process only included low labor force, open field, feedstock(e.g., grass and crop residue), and simple tools. The operation time for processing 10 kg of the corn residue by an individual farmer was 24.4 ± 4.1 min(n = 10). As compared with the conventional field burning process, the B-SC process drastically shortened the time for biomass burning and generated a significantly lower emission of smoke and thermal energy. This simple technique can be particularly practical and effective for farmers to improve the soils of poor quality in China.     

圆柱形燃烧室对发动机工况的影响

论述了速燃及新型燃烧室对发动机运行经济性及排放性能的影响,并对新型燃烧室的实验结果进行对比分析,指出了新型燃烧室的特点。     

森林燃烧中的特殊火行为研究进展

在森林火灾中, 当火强度达到一定程度时, 具有特殊的火行为现象。森林燃烧中的特殊火行为研究是国内外研究难点和重点之一, 特殊火行为的特征有:火强度急剧增加、可持续的火蔓延速度很快、空气对流十分容易、远距离飞火、火旋风或大片的水平火焰、风突然平静。特殊火行为的现象有火旋风、对流柱、飞火和火爆等。当火表现出以上这些特征和现象时, 它的强度就已经达到了常规的扑灭方法进行扑救很少有效的程度。在这种情况下, 扑救工作要在那些能够保证安全工作的部分火线上进行, 采取措施去保护宝贵的财产或资源。     

基于IAWA的3种简易木材识别方法探究

国际木材解剖学家协会手册举例3种简易识别材种方法,分别为泡沫测试、铬天青-S测试、燃烧灰烬测试,通过实验获得56个树种对应的3种鉴别特征。结果表明：56个阔叶材中有9种呈阳性反应、15种呈弱阳性反应、32种呈阴性反应;6个材种呈阳性铬天青颜色反应。在燃烧灰烬测试中,有10种呈亮白色灰烬、14种呈黄褐色灰烬、12种呈其他颜色的灰烬、19种呈带炭的灰烬,只有1种呈成炭。3种简易的木材鉴别方法能够有效收缩树种范围,同时能够为户外或进口原木的现场检验区分近似树种提供可行性依据。     

周期性计划烧除对森林生态系统的影响研究综述

周期性计划烧除是人类科学用火,进行营林管理的一种重要手段,具有经济实用性、生态保护性、降低火灾风险性、维护火生态顶级系统等优点。本研究从生境、森林植被、生物多样性等方面阐述了周期性计划烧除对森林生态系统的影响,展望了未来研究方向与趋势。研究结果有利于更好掌握生态系统计划烧除的基本规律,使火真正成为营林工具和手段,充分发挥火在森林生态系统发展过程中的积极作用,为计划烧除在林火管理中的应用提供参考依据。     

Aerobic and anaerobic burning alter trace metal availability in peat soils: evidence from laboratory experiments

As global warming becomes more pronounced, climate change and human activities are leading to frequent peat fire incidents. Fire plays an important role in the environmental distribution of trace metals in peat soils. In the current study, we collected peat soils from six peatlands of the Great Khingan Mountains in Northeast China, where wildfires have often occurred in recent decades. To investigate the transformation of trace metals in peat soils by fire, burning experiments at 250°C (light) or 600°C (severe) and under aerobic (AE, flaming) and anaerobic (AN, smouldering) conditions (AE250, AE600, AN250, AN600) were carried out in the laboratory to investigate the effect of different burning intensities on the distribution of Cu, As, Pb, and Cd in peat soils. The European Community Bureau of Reference (BCR) sequential extraction method for metal fractions was applied for partitioning four fractions (exchangeable, reducible, oxidizable, and residual). The results showed that AE600 significantly decreased the percentages of oxidizable Cu, As, Cd and Pb (Cu_oxi, As_oxi Cd_oxi and Pb_oxi) compared with those of the original samples, e.g., Cu_oxi decreased from 68.84% ± 12.76% to 15.82% ± 8.02% in peat under moss, which might result from organic matter decrease. Under AN250 conditions, the exchangeable As (As_exc) and Pb (Pb_exc) significantly increased by more than twice. Different burning intensities significantly changed the various fractions of Cu, e.g., more than 20% Cu_oxi transferred to exchangeable and reducible fractions as the temperature increased. Most of the available fractions of As transformed to residual As after burning. Our study suggests that the AE600 treatment increased the ecotoxicity and bioavailability of Cu, Pb and Cd in peat soils, while AN250 burning decreased the potential ecotoxicity of Cu, As, and Pb. Compared with lower temperature flaming burning (AE250), the ecotoxicity and bioavailability of Cu and Pb were greater in high temperature (AE600) conditions. Smouldering fires at both temperatures (AN250 and AN600) maintained a high potential ecotoxicity and bioavailability of Cu and Pb in peat soils.