新疆中低产田发展人工草地的初步研究

从新疆天然草地的利用，农业面临的问题出发，说明在绿洲内发展人工草地的必要性。针对全疆中低产田特点，将其分成7种基本类型。按类型总结出相应适生的饲草种类。通过人工种植这些饲草，达到合理利用改良耕地的目的，进而带动整个农业产业结构的调整，建立起适宜新疆农业发展的草地农业模式。     

Carbonyl sulfide and dimethyl sulfide fluxes in an urban lawn and adjacent bare soil in Guangzhou, China

Carbonyl sulfide (COS) and dimethyl sulfide (DMS) fluxes from an urban Cynodon dactylon lawn and adjacent bare soil were measured during April–July 2005 in Guangzhou, China. Both the lawn and bare soil acted as sinks for COS and sources for DMS. The mean fluxes of COS and DMS in the lawn (–19.27 and 18.16 pmol/(m2 sec), respectively) were significantly higher than those in the bare soil (–9.89 and 9.35 pmol/(m2 sec), respectively). Fluxes of COS and DMS in mowed lawn were also higher than those in bare soils. Both COS and DMS fluxes showed diurnal variation with detectable but much lower values in the nighttime than in the daytime. COS fluxes were related significantly to temperature and the optimal temperature for COS uptake was 29°C. While positive linear correlations were found between DMS fluxes and temperature. COS fluxes increased linearly with ambient COS mixing ratios, and had a compensation point of 336 ppt.     

Evaluation of the National Land Cover Database for Hydrologic Applications in Urban and Suburban Baltimore,Maryland1

Smith, Monica Lipscomb, Weiqi Zhou, Mary Cadenasso, Morgan Grove, and Lawrence E. Band, 2010. Evaluation of the National Land Cover Database for Hydrologic Applications in Urban and Suburban Baltimore, Maryland. Journal of the American Water Resources Association (JAWRA) 46(2):429-442. DOI: 10.1111/j.1752-1688.2009.00412.x Abstract: We compared the National Land Cover Database (NLCD) 2001 land cover, impervious, and canopy data products to land cover data derived from 0.6-m resolution three-band digital imagery and ancillary data. We conducted this comparison at the 1 km², 9 km², and gauged watershed scales within the Baltimore Ecosystem Study to determine the usefulness and limitations of the NLCD in heterogeneous urban to exurban environments for the determination of land-cover information for hydrological applications. Although the NLCD canopy and impervious data are significantly correlated with the high-resolution land-cover dataset, both layers exhibit bias at <10 and >70% cover. The ratio of total impervious area and connected impervious area differs along the range of percent imperviousness – at low percent imperviousness, the NLCD is a better predictor of pavement alone, whereas at higher percent imperviousness, buildings and pavement together more resemble NLCD impervious estimates. The land-cover composition and range for each NLCD urban land category (developed open space, low-intensity, medium-intensity, and high-intensity developed) is more variable in areas of low-intensity development. Fine-vegetation land-cover/lawn area is incorporated in a large number of land use categories with no ability to extract this land cover from the NLCD. These findings reveal that the NLCD may yield important biases in urban, suburban, and exurban hydrologic analyses where land cover is characterized by fine-scale spatial heterogeneity.     

降雨对城市草坪温室气体源汇效应的影响

利用静态箱法研究了夏季降雨对上海市城市草坪温室气体排放的影响,结果表明,晴天上海市城市草坪是N_2O和CO_2的源,CH_4的汇;降雨会削弱N_2O和CO_2排放,使得草坪由CH_4的汇转变为排放源。N_2O通量在晴天和雨后分别为1.37±3.47和1.06±2.67μmol/(m2·h),CO_2通量在晴天和雨后分别为13.33±8.59和6.46±2.61mmol/(m~2·h),CH_4通量在晴天和降雨后分别为-0.08±3.77和0.22±6.27μmol/(m~2·h)。明暗箱对比实验显示,草坪生态系统能有效缓解土壤对大气N_2O和CO_2的贡献。N_2O和CO_2通量与光合有效辐射和温度呈显著负相关(p0.01),CH_4和二者相关性不显著。降雨通过降低光合作用和温度,间接削弱城市草坪CO_2和N_2O的排放。降雨可能通过提高含水率抑制城市草坪对CH_4的吸收,促进其排放。     

Soil warming effect on net ecosystem exchange of carbon dioxide during the transition from winter carbon source to spring carbon sink in a temperate urban lawn

The significant warming in urban environment caused by the combined effects of global warming and heat island has stimulated widely development of urban vegetations. However, it is less known of the climate feedback of urban lawn in warmed environment. Soil warming effect on net ecosystem exchange (NEE) of carbon dioxide during the transition period from winter to spring was investigated in a temperate urban lawn in Beijing, China. The NEE (negative for uptake) under soil warming treatment (temperature was about 5℃ higher than the ambient treatment as a control) was -0.71 μmol/(m².sec), the ecosytem was a CO₂ sink under soil warming treatment, the lawn ecosystem under the control was a CO₂ source (0.13 μmol/(m².sec)), indicating that the lawn ecosystem would provide a negative feedback to global warming. There was no significant effect of soil warming on nocturnal NEE (i.e., ecosystem respiration), although the soil temperature sensitivity (Q₁₀) of ecosystem respiration under soil warming treatment was 3.86, much lower than that in the control (7.03). The CO₂ uptake was significantly increased by soil warming treatment that was attributed to about 100% increase of α (apparent quantum yield) and A_max (maximum rate of photosynthesis). Our results indicated that the response of photosynthesis in urban lawn is much more sensitive to global warming than respiration in the transition period.     

城市污泥堆肥用作草坪基质研究进展

针对城市污泥堆肥特点,阐述了国内外城市污泥堆肥用作草坪基质的研究现状。总结了污泥堆肥用于草坪生产存在的问题,并认为研究重点应放在污泥堆肥混合基质的组成、水肥管理技术、草种的筛选、规范堆肥生产和草坪质量综合评价标准及可能存在的环境问题等方面。另外,需要加大高新技术的投入促进产业化,以便为污泥堆肥用作草坪基质提供确实的理论指导和技术支持。     

浅析旋刀式草坪割草机产品质量状况

在当前市场经济条件下,草坪割草机产品质量问题尤为重要,直接关系到环境、人身安全、作业质量等。本文论述了国内草坪割草机产品质量现状及存在的主要问题,为了加强草坪割草机产品的质量管理,并提出了改进建议。     

试述我国草业的现况与前景

本文阐述了我国草业科学研究与草业产业的现状,发展草业具有良好的经济、环境、社会效益,是实施西部大开发战略,改善自然与人类居住生态环境,促进畜牧业良性循环,实现西部农民小康目标的一条必由之路,更是国家生态安全的一项救国之策。草业科学研究与草业产业化发展将成为我国一个新的经济增长点。     

DETERMINISTIC MODELS FOR PREDICTING RESIDENTIAL WATER CONSUMPTION1

ABSTRACT: Forecasts of future urban water demand traditionally have been made by the projection of historic trends in per capita consumption and population. This paper outlines the use of two deterministic models to forecast the residential component of urban water demand. The models incorporate specific representation of the activities which result in water consumption at each residence. Predictions of water use can then be made by modeling the changes expected in the number of these activities and the consumption for each such activity.     

Injuries associated with the use of riding mowers in the United States, 2002-2007

Context: To examine injuries among patients treated in an emergency department (ED) related to the use of a riding lawn mower.Design and Setting: Data were obtained from the National Electronic Injury Surveillance System for the years 2002-2007. National estimates of ED visits for injuries associated with the use of a riding lawn mower were analyzed. Narrative text entries were categorized to provide a detailed record of the circumstances precipitating the injury. Average annual rates were calculated and logistic regression analyses were employed to determine risk estimates for patient disposition and demographic characteristics related to ED visits for injuries associated with riding mowers.Results: From 2002 through 2007, there were an estimated 66,341 ED visits for injuries related to the use of riding lawnmowers in the U.S., with an average annual rate of 6.0 ED visits per 100,000 males, and 1.6 ED visits per 100,000 females. Older adults had higher rates of ED visits for injuries (7.2/100,000) than younger age groups. The most common injuries involved contusions (24%); sprains/strains (22%) and fractures (17%). The majority of patients (90%) were treated and released the same day. Results of logistic regression analyses revealed that older adults were more likely to be hospitalized when compared to younger age groups; and incidents involving rollovers [OR = 5.45 (95% CI = 3.22-9.23)] and being run over [6.01 (95% CI 3.23-11.17)] were more likely to result in hospitalization when compared to all other circumstances of injury.Conclusions: Riding mowers present injury patterns and circumstances that are different than those reported for push mowers. Circumstances related to injuries and age groups affected were varied, making prevention of riding mower injuries challenging. Application/Impact: Findings support the need to increase awareness and/or change the design of riding mowers with respect to risk of rollover injuries.