黑河地区夏季林火特点及灭火手段探讨

文章对黑河地区2004～2009年的夏季气象因子进行了分析,指出黑河地区夏季林火具有发生时间相对集中、发生次数呈上升趋势、多发生在偏远山区、主要为地表火、火因主要是人为所致等特点,强调使用直升机、专业机械化部队扑救该地区夏季林火具有优势,效果明显。     

水稻低碳生产研究进展

 稻田是甲烷(methane,CH4)和氧化亚氮(nitrous oxide,N2O)的重要发生源。稻田中CH4和N2O的产生、消耗以及传输过程受稻田土壤类型、水分条件、肥料种类、施肥量及方法、耕作模式和制度、水稻品种等多种因素影响。CH4和N2O具有不同的排放特性,很多研究结果表明,水稻生长期间的中期排水烤田、后期干湿交替能显著降低CH4排放量,但同时也可能促进N2O的排放,因此,如何同时减少CH4和N2O的排放量是实现稻田低碳生产的关键要素;另一方面,稻田土壤的碳固定也是使稻田系统从源转变成汇的关键技术。从水稻生产过程中CH4排放、N2O排放、稻田土壤有机碳动态、减排措施四个方面综述了近年来水稻低碳生产相关研究状况,重点总结了国内外有关影响稻田CH4和N2O排放的关键影响因素、增加稻田土壤有机质含量的主要措施以及各种减排措施的全球增温潜势评价研究,并对水稻低碳生产研究作了展望。     

氧化油脂造成畜禽氧化应激的途径及缓解措施

油脂是畜禽饲料中的高能组分,但在储存、加工和饲喂过程中易发生氧化酸败。氧化油脂直接或间接地导致动物体内自由基积累和维生素E含量下降,从而使畜禽发生氧化应激。文中论述了氧化油脂造成畜禽氧化应激的主要途径,以及如何采取相应的措施缓解氧化油脂对畜禽造成的不利影响。     

Effectiveness of Thinning and Prescribed Fire Fuel Treatments in Piñon-Juniper Woodlands of the Davis Mountains,West Texas,USA

We evaluated the effectiveness of four fire hazard mitigation techniques in piñon-juniper forests of the Davis Mountains Preserve in West Texas. Four replicate fuel treatments (thin only, thin + burn, burn only, and control) were implemented to assess the effects of fire and fire surrogates on fuel loadings. The results suggested that the thin only and the thin + burn treatments significantly altered fuel loadings. The thin + burn treatment resulted in a 63% reduction in tree density, the thin only treatment resulted in a 23% reduction, and the burn only treatment showed an 8% reduction. Seedling density and tree basal area were not significantly affected by the treatments. Although thinning and thinning + burning were the most effective for reducing live fuels, they generated significant increases in surface fuels. Our results suggest that more aggressive thinning operations that target larger trees and prescribed burning during hotter, drier conditions could enhance future fuel management treatments in piñon-juniper woodlands in this region.     

高速公路建设造成的水土流失影响及减缓措施

指出了公路工程项目属于建设性项目,穿越地形地貌复杂多样,扰动地表程度及形式复杂多变,对沿线水土流失影响较大。以高速公路环境影响评价为例,对公路建设造成的水土流失影响进行了分析和阐述,提出了可采取的减缓措施。     

Effects of intensification of pastoral farming on greenhouse gas emissions in New Zealand

Abstract

AIMS: The aims of this cross-sectional study were to investigate the herd and cow-level prevalence of bovine digital dermatitis (BDD) in dairy farms in the northern Taranaki region of New Zealand, and to identify whether there was any spatial clustering of herds with the disease.

METHODS: A survey of 224 dairy farms in the northern Taranaki region of New Zealand was undertaken from September 2014 to February 2015. Following training in robust criteria to confirm BDD visually, a technician inspected the rear feet of every milking cow on the farms during milking. The identity of cows with lesions and the feet involved were recorded. The proportion of cows affected among the inspected population (cow-level prevalence), the proportion of a herd affected (farm-level prevalence), and proportion of farms with ≥1 cow with lesions, were calculated. A bivariate K function analysis was then used to assess whether farms with ≥1 cow with lesions were clustered, after accounting for the distribution of the farms involved in the study.

RESULTS: Bovine digital dermatitis lesions were observed on 143/224 (63.8 (95% CI=57.5–70.1)%) farms. Within-farm prevalence was 0% on 81 (36.2%) farms, between >0 and <3% on 120 (53.5%) farms, with a maximum prevalence of 12.7% on one farm. Overall, cow-level prevalence was 707/60,455 (1.2 (95% CI=0.9–3.0)%), and on affected farms was 707/41,116 (1.7 (95% CI=1.4–2.1)%). In affected cows, 268/707 (37.9%) had a lesion on left foot only, 262/707 (37.1%) on the right foot only and 177/707 (25.0%) on both feet. The K function analysis showed no evidence of clustering of farms with BDD.

CONCLUSIONS: Bovine digital dermatitis was widespread among the survey farms, but there was no evidence that there was any clustering of herds with BDD. The cow-level prevalence on affected farms was much lower than reported elsewhere.

CLINICAL RELEVANCE: Although the prevalence at the cow level was low, if these data are representative of other regions of New Zealand, BDD could easily become a major problem on dairy farms in New Zealand, as has been observed in other countries.     

成人高等教育教学方法与手段的创新研究——以兽医微生物学课程为例

以兽医微生物学课程为例,根据成人高等教育的特点,在教学内容、教学方法、教材建设等方面进行了初步探讨,就如何提高教学效果、加强实践教学、培养学生的思维能力和动手能力提出了一系列改革措施,并就成教师资队伍建设提出了一些建设性建议。     

鄂西烟草种植区气象灾害的时空变化分析

为明确气候变化对鄂西烟草气象灾害危险性的影响,基于已建立的干旱、低温冷害、连阴雨、暴雨、高温热害的危险性指标体系,利用鄂西18个国家气象站观测数据开展近60年来烟草高影响气象灾害的危险性指数分析,并进行前30 a和后30 a的对比。结果表明,从时间维度看,后30 a鄂西烟草种植区干旱、连阴雨和暴雨危险性总体有所减轻;而鄂西南干旱危险性加重,水分条件逐渐成为影响当地烟叶生产的主要因子之一。在气候变暖背景下,低温冷害和高温热害的危险性分别呈现出部分减轻和普遍加重的趋势。分区域来看,枣阳、南漳等地持续受干旱影响,低温冷害集中在高海拔地区,高温热害则分布于河谷地带。五峰、兴山是冰雹、大风的相对高发中心,需防范强对流天气带来的危害。鄂西地区由于地理位置不同,影响烟叶生产的主要气象灾害及气候变化有所差异。从综合气象灾害危险性分布来看,除巴东北部、建始北部局地外,后30 a恩施大部分地区气象灾害综合危险性等级仍在“中等”及以上,以鹤峰最为严重。     

风景园林应对气候变化的创新路径

当前气候变化导致的自然灾害增加以及国家碳达峰碳中和目标为风景园林发展带来了历史机遇,但风景园林在我国气候变化应对中的话语权仍显不足。为提升风景园林在应对气候变化中的学科地位,厘清风景园林在气候变化应对领域的责任和担当,探索风景园林气候设计的创新路径,本研究在综合分析国内外气候变化应对相关文献和政策措施的基础上,从气候变化的减缓和适应两个方面,考察了风景园林能够做出重要贡献的领域。结果显示,风景园林应该面向气候变化适应、灾害治理、碳达峰碳中和等国家需求,加强多学科的交叉融合,一方面通过气候积极性设计在城乡人居环境中固碳增汇、降低碳排放,另一方面通过景观规划设计适应气候变化,降低灾害风险,增强城乡韧性。风景园林气候设计的创新路径包括：标准化定向、空间化定量转向、生态完整性取向、多尺度面向以及教学改革创新。从以上结果可以看出,风景园林在应对气候变化中大有可为,气候设计的创新探索可推动风景园林学科范式转型和创新发展,并为应对气候变化提供中国方案。     

新建高压输电线路对管道干扰预测及缓解措施

为了判断某新建高压输电线路对埋地管道交流干扰程度并采取相应的缓解措施,利用数值模拟技术结合现场测试校正,建立了管道交流干扰计算模型,预测了新建高压输电线路对管道的交流干扰程度,并根据管道周围环境特点设计了深井地床排流缓解措施。测试结果表明:数值模拟计算结果与现场实测结果基本吻合,验证了合理设计深井地床能够有效缓解管道交流干扰的事实。实际工况的复杂性使得计算模型不可能与现场情况完全一致,对于新建输电线路,可利用附近已有的输电线路对计算模型进行校正。