基于Sentinel-2数据的苏州消夏湾生态安全缓冲区植被生长状况遥感监测评估

利用2021—2022年Sentinel-2卫星搭载的多光谱成像仪（MSI）遥感数据，通过SNAP遥感软件提供的植被生物物理参数处理模块（Biophysical Processor），反演了苏州消夏湾生态安全缓冲区的5种植被生物物理参数，包括植被吸收光合有效辐射比例（FAPAR）、植被覆盖度（FVC）、叶面积指数（LAI）、冠层叶绿素含量（CCC）和冠层含水量（CWC），开展植被生态环境监测评估研究。结果表明，该生态安全缓冲区2021年建成并投入运行后，植被覆盖度和生物量有所增加，区域植被冠层结构有所改善，植被生物物理参数从一定的角度反映了消夏湾生态安全缓冲区发挥了生态涵养成效。该研究方法能在大尺度上快捷、高效地反演植被生物物理参数，可为通过植被遥感动态监测评估生态安全缓冲区的生态功能提供有益的借鉴。     

Determination of pendimethalin (PROWL®480 EC) spray drift from ground applications

Abstract

Pendimethalin herbicide (PROWL^®480 EC) spray drift was determined from ground applications representing the highest rate applied to corn in eastern Canada. A novel drift collector pattern was laid out on the ground immediately before herbicide application. Most of the drift collectors were located downwind of the application target area. The maximum labelled rate of 1.68 kg ai/Ha was applied on 2 occasions on separate sites. In both applications, drift collector cards indicated that concentrations of pendimethalin were not detectable outside the target zone (<0.01 μg/cm²) at or beyond the 10 metre drift collector stations. Risk assessment calculations indicated that non‐target organisms would not be at significant risk from off‐site movement of pendimethalin.     

IMPACT OF COAL SURFACE MINING AND RECLAMATION ON SUSPENDED SEDIMENT IN THREE OHIO WATERSHEDS1

ABSTRACT: Prior to PL95–87 little research had been conducted to determine the impacts of mining and reclamation practices on sediment concentrations and yields on a watershed scale. Furthermore, it was unknown whether sediment yield and other variables would return to undisturbed levels after reclamation. Therefore, three small watersheds, with differing lithologies and soils, were monitored for runoff and suspended sediment concentrations during three phases of watershed disturbances: undisturbed watershed condition, mining and reclamation disturbances, and post‐reclaimed condition. Profound increases in suspended‐sediment concentrations, load rates, and yields due to mining and reclamation activities, and subsequent drastic decreases after reclamation were documented. Even with increases in runoff potential, reductions in suspended‐sediment concentrations and load rates to below or near undisturbed‐watershed levels is possible by using the mulch‐crimping technique and by removing diversions. Maximum concentrations and load rates occurred during times of active disturbances that exposed loose soil and spoil to high‐intensity rains. Sediment concentrations remained elevated compared with the undisturbed watershed when diversions were not well maintained and overtopped, and when they were not removed for final reclamation. Diversions are useful for vegetation establishment, but should be maintained until they are removed for final reclamation after good vegetative cover is established.     

A pilot study on the effect of Cu,Zn, and Cd on the spectral curves and chlorophyll of wheat canopy at tiller stage

The aim of this study was to investigate canopy spectral reflectance responses to different levels of heavy metals copper (Cu), zinc (Zn), and cadmium (Cd) induced stress. Random blocks design experiment was conducted to simulate Cu, Zn, and Cd at five concentration levels. Chlorophyll and visible and near infrared canopy reflectance were measured for each treatment 56 days after seeding using chlorophyll meter SPAD-502 and spectroradiometer, respectively. New vegetative indices termed ratio of inclination angles (RIA), MERIS (the medium resolution imaging spectrometer) terrestrial chlorophyll index (MTCI), and normalized difference vegetation index (NDVI) were used to assess the response of canopy spectral reflectance to different heavy metal levels. Significant spectral variability especially in blue, red, and near infrared reflectance was observed for different heavy metal treatments. One-sample test showed significant difference for NDVI, MTCI, and RIA among five-level treatments at the 0.01 level. Correlation analysis demonstrated that the two vegetative indices (RIA and MTCI) were significantly correlated with chlorophyll meter values for Cd, Cu, and Zn treatments. However, NDVI was only significantly correlated with chlorophyll meter values for Cu and Zn treatments. Linear regression analysis also illustrated that RIA and MTCI were potential indices for predicting chlorophyll concentration with significant F test under Cu-, Zn-, and Cd-mediated stress.     

城市道路中央隔离设施的交通安全与景观研究

笔者从道路交通事故和景观方面 ,研究道路中央隔离设施的功能与特征。首先 ,利用对某城市道路中央有无隔离带情况下记录的交通事故数据 ,进行交通安全统计比较分析 ;其次 ,分别利用层次分析法和语言分级评价法 ,对城市道路中央双黄线、中央护栏隔离和中央绿化隔离 3种情况的景观进行分析 ;最后 ,通过综合分析给出分析结果 ,即中央绿化隔离、中央栅栏隔离带和双黄线隔离的评价顺序。     

WATER CHEMISTRY OF NORTHERN GREAT PLAINS STRIP MINE AND LIVESTOCK WATER IMPOUNDMENTS1

The water from 34 strip mine and 9 livestock water impoundments on the Northern Great Plains was analyzed. In all areas the water was classified as slightly brackish or saline. The dominant ion sequence for the study ponds was Na>Ca>Mg>K and SO₄HCO₃CO₃Cl, which differs from most freshwater by the transposition of Na and SO₄. Even though mean concentrations of total filterable residue were consistently greater in strip mine ponds, statistically significant differences were not found at the p ≤ 0.05 level between strip ponds and livestock ponds. The macronutrients of nitrogen and phosphorus found in the ponds were neither limiting to primary productivity nor excessive for fresh water. Many ponds contain turbid water. Turbidity restricts light penetration and limits photosynthesis besides making the ponds visually unattractive. The source of water for the pond, whether surface runoff or groundwater, seems to have important bearing on turbidity. The most appropriate use of these strip mine ponds is for waterfowl, warm-water fisheries, and other wildlife associated with prairie wetlands. However, even these uses are jeopardized by detrimental concentrations of trace elements in the water (Anderson and Hawkes, 1984).     

An Assessment of Management Practices to Control Nutrient and Pesticide Levels in Vegetable Production Areas in the Rattaphum Catchment, Thailand

The over-use of agrochemicals may have adverse effects on soils along with surface and groundwater. An assessment of alternative management practices to reduce the application of agrochemicals and minimise the pollution of water resources was carried out in the vegetable agro-ecosystem in the Rattaphum Catchment. This paper details the factors that govern the volume of agrochemicals used on high intensity crops in this area, covering the choice of crop and cropping patterns, level of pest and weed infestation and the socio-economic status of farmers such as capital, size of holding and labour availability. Alternative management practices tested included (i) a reduction in the use of pesticides and chemical fertilisers; (ii) the use of bio-insecticides and bio-fertilisers; and (iii) the development of buffer zones near streams to reduce nutrient leaching into surface water systems. The results showed that when compared with bio-insecticides, synthetic insecticides were more effective in controlling major insect pests during chaisim vegetable production and were associated with higher net incomes. The high rate of application of chemical fertilisers in home gardens and commercial farms led to the accumulation of phosphorous and potassium in the top soil, with the traditional method of combining organic and chemical fertilisers producing the highest total nitrogen soil content. A fifty percent reduction in chemical fertilisers in the commercial farms produced the lowest total nitrogen soil content, without any apparent change in crop yield. The three types of tested buffers seem to be effective in reducing runoff and sediment load and were particularly efficient in lowering nutrient leaching to streams; the best results were obtained with an effective length of 2.5 m.     

吹吸式通风法在冷轧带钢氧化铁皮除尘中的应用

依据吹吸式通风原理,设计了一种氧化铁皮粉尘污染控制装置,通过对吹气、吸气罩的理论计算及实验分析,提出了具体的设计参数,为冷轧带钢氧化铁皮粉尘的控制提供了依据。     

厌氧消化体系的酸碱性及其缓冲能力

厌氧消化体系的酸碱性及其缓冲能力是影响系统运行状况的重要因素。为研究体系的pH值和缓冲能力的大小及其变化规律,依据溶液电中性理论,在充分分析厌氧消化体系内影响酸碱性的诸多因素和过程的基础上,建立了消化液的电荷平衡方程,以此表明体系内的多相化学平衡。通过对方程确定的pH值随有机酸浓度变化曲线的讨论,指出有机酸浓度对消化液pH值的影响受体系中氨、磷酸、钙、其它离子含量及气相二氧化碳分压的制约,曲线拐点处的有机酸含量反映体系的最大缓冲能力,该值可由近似公式求得,并提出对消化液的pH值及体系的缓冲能力实施控制的途径。