日光温室越冬茬黄瓜播期对雌花数量的影响

试验研究了日光温室越冬茬黄瓜播期对雌花数量的影响，结果表明，从9月17日-10月6日分期播种，播种时间越晚，前l-12节平均单节雌花数越多，13-20节差异不明显。日光温室栽培黄瓜，周期性座果现象依然十分明显。     

Nitrous oxide dynamics during denitrification along a hydrological gradient of subtropical grasslands

Nitrous oxide (N₂O) dynamics during denitrification, including N₂O production and reduction, particularly as related to soil depth, are poorly understood. The objective of this study was to investigate the rates of N₂O production and reduction processes at various soil depths along a hydrological gradient in grazed subtropical grasslands. A batch incubation study was conducted on soils collected along a hydrological gradient representing isolated wetland (Center), transient edge (Edge) and pasture upland (Upland) in south-central Florida. Significantly different N₂O production and reduction rates between hydrological zones were observed for surface soils (0–10 cm) under ambient conditions, with average N₂O production rates of 0.368, 0.178 and 0.003 N₂O-N kg⁻¹ dry soil h⁻¹ for Center, Edge and Upland, respectively, and average N₂O reduction rates of 0.063, 0.132 and 0.002 N₂O-N kg⁻¹ dry soil h⁻¹. Nitrous oxide production and reduction in subsurface soils maintained low rates and showed small variations between depths and hydrological zones. Our results suggest that N₂O dynamics were affected by depth, mainly through labile organic carbon (C) and microbial biomass C, being influenced by hydrological zone primarily through soil NO₃^- content. The spatial distribution of N₂O fluxes from denitrification along the hydrological gradient is likely attributed to the differences in N₂O production and reduction in surface soils.     

南方双季稻区不同复种方式对稻田综合温室效应的影响

为明确南方双季稻区不同复种方式对稻田综合温室效应和温室气体排放强度的影响,试验设置油菜-一季中稻(R-MR)、冬季绿肥(紫云英)-早稻-晚稻(GM-ER-LR)、冬闲-早稻-晚稻(WF-ER-LR)3个处理,采用静态暗箱-气相色谱法监测周年温室气体排放,探明不同复种方式对周年作物产量、稻田全球增温潜势(GWP)、籽粒能量产出(GEY)和全球增温潜势强度(GWPI)的影响。结果表明,与R-MR相比,GM-ER-LR和WF-ER-LR显著增加了CH₄累积排放量(分别提高1.27倍和1.18倍),显著降低了N₂O累积排放总量(分别降低34.1%和49.4%),GM-ER-LR和WF-ER-LR的CH₄和N₂O累积排放量无显著差异。与R-MR相比,GM-ER-LR和 WF-ER-LR显著提高了周年GEY(分别提高28.6%和27.0%)。在100年时间尺度上,GM-ER-LR和WF-ER-LR的稻田GWP分别是R-MR的1.27倍和1.18倍,GWPI分别较R-MR提高100%和50%。因此,GM-ER-LR和WF-ER-LR有利于提高作物产量,但会增加稻田综合温室效应和温室气体排放强度。鉴于双季稻区中稻面积有增大的趋势,综合环境效益和经济效益,油菜-一季中稻减排增效效果更好。     

郑州地区日光温室辣椒越冬—大茬高效生产技术

笔者通过多年的生产实践研究，总结出了适合郑州地区的日光温室辣椒越冬—大茬高效生产技术，包括品种选择、播种育苗、定植、田间管理、采收、主要病虫害防治等方面。     

浅谈巴彦淖尔市日光温室蔬菜不能越冬生产成因

通过调查分析,造成巴彦淖尔市日光温室不能越冬生产果类菜的主要原因与温室的结构、建造材料有关,即温室的墙体不达标、没有设置防寒沟、后屋面不达标以及温室前屋面覆盖材料不过关等因素造成.     

新型温室除雪机在农业温室中的应用研究

冬季北方地区温室屋面除雪是农业部门研究的热点问题之一,为解决屋面积雪压塌温室这一问题,设计了一种新型温室除雪机,并对其除雪机构、输送机构及功率消耗进行了理论计算和试验验证。研究表明:采用硬质毛刷和螺旋机构制成的除雪机,适合清扫屋面的较厚积雪,减小了除雪过程中的阻力,降低了农民的劳动强度。理论分析和样机试验较吻合。试验表明,整机结构合理,具有很好的除雪效果,达到了预期设计目标。     

Greenhouse gas balance of harvesting stumps and logging residues for energy in Sweden

Abstract

In this case study, forest fuel procurement chains of stumps and logging residues were evaluated using a Life Cycle Assessment perspective. Direct emissions from combustion were not included, but soil organic carbon change was included as changes in carbon stocks in litter and soil. The results showed that primary forest biomass for energy has a climate impact which is time dependent. However, in long-time perspectives, there are large greenhouse gas (GHG) savings. In a short-term (20 years), there were no GHG savings when natural gas or coal was replaced. This is due to the fact that the harvest lead to decreased input of organic matter to the soil which is compared to a reference where biomass are left to decompose. The reduction in soil organic carbon may have been underestimated in the stump harvest systems studied, as the effect of soil disturbance per se was not included. Important factors when assessing GHG balance of forest fuels, besides the time horizon used, were site productivity, geographical position and forest fuel resource (stumps or logging residues). When assessing the greenhouse gas savings, efficiency of the end-use, allocation method between heat and power and type of fossil fuel replaced were also important.     

不同生态环境及青椒长势和产量的比较

为了解决同一大棚里连续种植青椒几年后出现的减产问题,对以改善棚内青椒生态环境为目的而组装的集成技术设施棚与采用常规技术棚进行了大区互比试验,并于试验区内同一条件下对棚膜透光、棚温变化、浇水与土壤含水量、棚内气流、施肥量、病虫害发生以及青椒长势和产量进行了定点调查。结果显示:设施集成技术棚较采用常规技术棚(对照)的生态环境有明显改善;青椒长势明显整齐;单株增加精品果产量和结果数达到显著与极显著水平,增产33%。经过比较后认为,目前简易大棚青椒生产上出现的减产问题是生态环境不良所致。试验的设施集成技术棚为解决现存问题提供了可能。     

设施农业可再生能源综合供能系统运行策略

针对当前温室生产中传统能源系统能源利用率低、环境污染严重、运行费用高等问题，该研究设计了一种耦合太阳能与空气能利用的可再生能源系统，考虑设备季节性利用制定了4种不同的运行策略，并在典型日与全年两种维度上与传统系统进行了热力、环境、经济方面的对比分析。结果表明，典型日内系统一次能源节约率、二氧化碳减排率、运行费用节约率分别为24.67%、23.22%、17.04%。全年维度内策略1、2、3、4对应的一次能源节约率分别为60.23%、70.43%、70.53%、63.69%，二氧化碳减排率分别为222.90%、266.35%、269.56%、223.00%，运行费用节约率分别为227.12%、272.38%、302.56%、239.81%，投资回收期分别为2.51、2.35、2.21、2.09a。该研究揭示了系统全年、典型日运行中的能量特性，证明了可再生能源系统在农业方面应用的可行性、优越性，与此同时也发现空气源热泵的运行时间长短及时刻差异是影响系统综合性能的重要因素，为面向温室的可再生能源系统的发展提供思路与参考。     

Contribution To Climate Change Of Forest Fires In Spain: Emissions And Loss Of Sequestration

ABSTRACT

Forest fires contribute to climate change mainly due to emission of greenhouse gases by biomass burning and loss of sequestration by sink destruction. The average contribution in Spain between 1998 and 2015 was 9,494,910 Mg CO_{2 eq} per year, 23.8% from biomass burning and 76.2% from loss of carbon sequestration, the latter three times higher than the former, although the emissions from combustion are usually the only accounted. Regarding to the vegetation burned, 43.6% of emissions come from forest (17.7% conifers, 4.8% hardwoods and 21.1% Eucalyptus), 53.7% from scrublands and 2.7% from grasslands. The loss of sequestration is 6.6% in the fire year and by 93.4% in previous years. Scrubland burning produces a greater amount of emissions than forests, but forest regeneration is slower, with greater influence on the loss of sequestration. It is essential a forest management focused on increase fire resilience and adaptation to climate change, increase the effectiveness of extinction works to reduce fire damages and implement actions to recover the burnt vegetation, because the loss of sinks is a critical aspect.