火烧和砍伐对疏叶骆驼刺叶片生态化学计量特征的影响

以塔克拉玛干沙漠南缘绿洲—沙漠过渡带的优势植物——疏叶骆驼刺为研究对象,设置春季砍伐、春季火烧、秋季砍伐和对照处理,研究了干扰对疏叶骆驼刺叶片N,P,K生态化学计量特征的影响。结果表明:春伐和火烧处理下,疏叶骆驼刺叶片N,P和K含量随季节变化显著降低,而N∶P无明显差异;秋伐处理下,叶片N含量及N∶P先降低后上升,K含量先升高后降低,P含量则无明显差异。不同干扰下疏叶骆驼刺叶片N,P,K含量及其N∶P的季节变异分析显示,火烧处理下其N,P,K季节变异最大,分别为:22.32%,20.43%,28.27%;春伐处理下,N及N∶P季节变异最小,分别为16.29%,8.67%;秋伐处理下P季节变异最小,为8.64%;对照处理下,K季节变异最小,为8.11%,N∶P季节变异最大,为24.26%。生长季节与干扰处理对疏叶骆驼刺叶片N,P,K含量及其N∶P影响的方差分析显示,疏叶骆驼刺叶片N及N∶P主要受生长季节与干扰的交互作用影响,而P及K含量主要受生长季节的影响。     

The Sage-Grouse Habitat Mortgage: Effective Conifer Management in Space and Time

Management of conservation-reliant species can be complicated by the need to manage ecosystem processes that operate at extended temporal horizons. One such process is the role of fire in regulating abundance of expanding conifers that disrupt sage-grouse habitat in the northern Great Basin of the United States. Removing conifers by cutting has a beneficial effect on sage-grouse habitat. However, effects may last only a few decades because conifer seedlings are not controlled and the seed bank is fully stocked. Fire treatment may be preferred because conifer control lasts longer than for mechanical treatments. The amount of conservation needed to control conifers at large temporal and spatial scales can be quantified by multiplying land area by the time needed for conifer abundance to progress to critical thresholds (i.e., “conservation volume”). The contribution of different treatments in arresting conifer succession can be calculated by dividing conservation volume by the duration of treatment effect. We estimate that fire has approximately twice the treatment life of cutting at time horizons approaching 100 yr, but, has high up-front conservation costs due to temporary loss of sagebrush. Cutting has less up-front conservation costs because sagebrush is unaffected, but it is more expensive over longer management time horizons because of decreased durability. Managing conifers within sage-grouse habitat is difficult because of the necessity to maintain the majority of the landscape in sagebrush habitat and because the threshold for negative conifer effects occurs fairly early in the successional process. The time needed for recovery of sagebrush creates limits to fire use in managing sage-grouse habitat. Utilizing a combination of fire and cutting treatments is most financially and ecologically sustainable over long time horizons involved in managing conifer-prone sage-grouse habitat.     

不同干扰处理对骆驼刺茎、叶、刺器官化学计量特征的影响

以塔克拉玛干沙漠南缘沙漠—绿洲过渡带的优势植物种骆驼刺(Alhagi sparsifolia Shap.)为研究对象,设置当年春季砍伐、春季火烧,上一年秋季砍伐和对照处理,研究刈割和火烧对骆驼刺不同器官N、P、K化学计量特征的影响。结果表明:不同干扰处理下骆驼刺不同器官N、P、K含量及其N∶P比差异显著,并且在不同生长阶段变化规律不一致,其平均N、P、K含量以及N∶P比均为叶片高于茎和刺。在骆驼刺的生长阶段(8—10月),叶和刺中均为P含量及N∶P比的季节变异较小,N及K含量的季节变异较大;茎中N及K含量的季节变异较小,P含量及N∶P比的季节变异较大。对骆驼刺N、P、K含量及其N∶P比的多因素方差分析显示,骆驼刺N和P主要受不同器官的影响,而K和N∶P比主要受生长阶段的影响。     

中国秸秆废弃焚烧与资源化利用的经济与环境分析

本研究就农作物秸秆资源废弃焚烧与资源化利用的经济效益与环境效益问题进行了分析和讨论。研究系统归纳了国内学术界有关秸秆焚烧现状、原因、危害以及秸秆资源化利用的经济和环境效益等方面文献。研究显示,秸秆废弃焚烧已成为中国显著的环境和社会问题,而农户之所以会焚烧秸秆是由于收获和利用秸秆的机会成本过高,且收益较低;秸秆发电、秸秆气化集中供气等新型秸秆资源化利用技术的环境效益明显,但经济效益受技术、原料、市场等因素影响存在不确定性;秸秆收储运成本高及相关体系不完善,成为制约秸秆规模化利用的关键因素。总体上看,现有技术的综合效益不明显,这限制了中国秸秆资源化利用水平的提高,急需政府扶持以进一步推动相关领域的技术创新。     

专业种植大户迫切需要的农业社会化服务是什么?——基于对黑龙江省的调查

伴随农业生产向专业分工、社会化协作方式转变,农业社会化服务对农业生产发挥越来越重要的作用,充分掌握农业社会化服务的主体需求性,并系统分析影响需求的决定因素,是实现农业现代化的关键。鉴于此,本文基于农户行为理论,以黑龙江省专业种植大户为研究对象,运用二元Logistic回归模型,分析专业种植大户对农业社会化服务的需求,探讨其需求的影响因素。结果表明,专业种植大户对农业社会化服务需求意愿较为强烈,且最迫切需要的农业社会化服务分别是农业信息服务、农业生产资料供应服务和农业技术服务3项,需求率分别为56.88%、56.61%和54.76%。性别、受教育程度、务农劳动力规模、农地规模、土地细碎化程度、种植收入占比、对现有服务的评价、是否担任村干部、是否加入合作社、是否参加过农业培训对农业社会化服务需求有正向影响,年龄、务农劳动力是否兼业对农业社会化服务需求有负向影响。因此,提出要创新服务供给形式、注重契合主体需要,统筹各类农户主体特征、兼顾不同主体需求满意度,巩固农民专业合作社发展地位、完善农民专业合作社服务功能等政策建议。     

Behavior as a tool for assessing a managed landscape: a case study of the Karner blue butterfly

In an increasingly human-dominated landscape, effective management of disturbance-maintained ecosystems, such as grasslands and savannas, is critical to the conservation of biodiversity. Yet, the response of individual organisms to landscapes created by disturbances and management is rarely studied. In this study, we examined the endangered Karner blue butterfly, Lycaeides melissa samuelis, in a heterogeneous oak savanna. Our objective was to quantify the butterfly’s habitat use and behavior to assess the effects of prescribed burning. The oak savanna management in Ohio, USA divides each Karner blue site (n = 4) into three units. Each one-third unit is then burned, mowed, or unmanaged in an annual rotation within each site, and the result is a fire return interval of ~3 years. Our surveys measured habitat use, while behavior observations quantified reproduction and foraging for the two annual broods. Our habitat use results showed burned treatments were recolonized quickly, but there was not a clear selection for burned treatments. Foraging rates were similar in all treatments; however, females oviposited significantly less in unmanaged treatments (only 5 of 127 ovipositions). This oviposition preference was likely due to habitat degradation and the availability of recently burned, early successional habitat. Since Karner blues avoided reproduction in units unburned for ≥4 years, these units could be burned to create high quality early successional habitat. These results demonstrate how behavioral decisions can be pivotal forces driving spatial population dynamics. Our case study demonstrates how a fine-scale landscape perspective combined with measurements of behavioral processes can assist with management decision-making.     

我国秸秆发电技术的应用及前景

根据我国目前能源紧缺和秸秆资源利用水平低的现状,介绍了国内秸秆发电技术的研究和应用情况.分别阐述了秸秆直接燃烧发电、秸秆与煤混合燃烧发电和秸秆气化发电3种发电形式的技术原理、工艺流程和工程应用情况.结合工程实践经验,分析了秸秆发电技术应用中存在的问题,从秸秆收集、技术改进、国家配套政策等3个方面提出了建议,指出我国秸秆发电技术和产业将进入一个快速发展时期.     

秸秆捆烧清洁供暖技术评价

中国北方地区秸秆资源丰富,将秸秆打捆转化为能源实现清洁取暖,既能解决秸秆过剩问题,又能有效替代煤炭,对改善大气质量和人居环境具有重要意义。为探究秸秆捆烧清洁供暖技术的能源效率、经济效益和温室气体排放,采用3E（Economic,Energy and Environment）评价模型,从作物种植收获到秸秆捆烧供暖应用全过程开展系统评价,结果表明,秸秆捆烧供暖技术的能源和经济效益较好、温室气体排放少,适于居住较集中的村镇地区冬季供暖,也可用于农业、工业园区等区域供热。供暖面积0.5×104～10×104m2范围内,供暖面积越高,能源和经济环境效益越好,秸秆捆烧供暖的净能量10 512～10 774.8 MJ/t,能量产出投入比8.4～8.5,能源转化率较高,温室气体CO2当量排放量为9.67～11.21 g/MJ;技术经济成本391.1元/t（折合16.2元/m2）～560.5元/t（折合23.8元/m2）,按基准收益率8%计算,供暖规模应不小于2×104 m2,若不考虑折旧只考虑运行成本,则供暖面积应不小于1×104 m2。与秸秆成型燃料和秸秆炭气联产供暖技术比较,均具有较好的经济效益,秸秆捆烧供暖技术的能量效益最优,温室气体排放量最少。与煤炭供暖技术相比,3种秸秆供暖技术的净能量产出不如煤炭,但温室气体排放仅为煤炭的1/10～1/7,秸秆清洁供暖技术的环境效益显著。     

基于Host Link 通信的燃气炉自动控制系统

介绍了基于高速调温烧嘴燃气加热炉的全自动计算机智能控制系统的方案,实现自动点火、自动监测火焰、脉动式燃烧、自动控温、熄火报警保护、数据的显示与记录等功能,并采用CPM1AH的Host Link 通信功能及智能PID控制技术,合理优化控制,使燃气在炉内能充分燃烧.采用燃气炉自动控制系统,既节省能源,又减少了大气的污染,同时保护了环境.     

Carbon cycling and sequestration opportunities in South America: the case of Brazil

Abstract. A carbon emission inventory of the Brazilian agricultural sector was used to compare greenhouse gas emissions with estimated carbon offsets promoted by two main changes in agricultural management: the replacement of conventional tillage by no-tillage and the cessation of annual burning in sugar cane production. Using the IPCC revised 1996 guidelines for national greenhouse gas inventories, we estimate that 12.65 Mt C are emitted annually from agricultural land in Brazil. Ongoing conversion of conventionally tilled land to no-tillage currently accumulates 9 Mt C yr⁻¹. Industrial by-products like alcohol and bagasse from sugar cane processing substitute fossil fuel for transportation and power generation offsetting 10 and 8 Mt C yr⁻¹, respectively. An additional opportunity for 0.53 Mt C yr⁻¹ sequestration is presented by avoiding burning before harvesting of sugar cane. These data show that there could be almost full compensation between sources and sinks/offsets in the agricultural carbon cycle. There is a great opportunity to achieve this mitigation benefit because the adoption of new technologies is increasing rapidly.