农业景观农地和非农绿地斑块属性特征及其结构优化研究——以河南省封丘县为例

现代农业的发展导致大量非农绿地斑块从农业景观中消失,结构简单、类型单一的农业景观使得农业生态系统功能与服务遭到了严重制约。本研究选择了黄河中下游平原的河南省封丘县为研究区域,结合遥感影像调查和景观格局分析,对研究区绿地斑块进行提取和分类,并着重分析了该区域农田基质大背景下的非农绿地斑块的结构属性特征。研究结果显示,研究区总体绿地率较低,绿地斑块总面积较小;人工林为优势绿地斑块类型,但多围绕居住区分布,呈现环状的分布特征;斑块类型较为简单且空间分布比较分散,斑块多样性指数较低,破碎化程度较高。建议加大对研究区绿地斑块的改造,通过增加斑块类型、设计农田边界、加强不同类型斑块间的连接度等措施,提高农业景观中绿地斑块的数量与质量。本研究为进一步探讨研究区景观结构的合理布局,并为今后多功能景观的构建奠定理论与实践基础,具有重要的研究意义。     

银川市景观格局动态变化研究

应用遥感和GIS技术对城市化过程中城市景观格局及其动态过程进行研究,可以更好地认识研究区的空间特征及其景观要素的演替。选取2001年和2005年的银川市CBERS图像,提取研究区两个时期的景观类型,并选取斑块面积、斑块数量、景观多样性指数、景观优势度指数、景观均匀度指数和景观破碎度指数等景观生态指标,对研究区的景观格局进行了分析。结果表明:在研究时段内景观斑块类型没有发生变化,景观多样性指数和均匀度指数增加,优势度指数和破碎度指数有所减小,研究区的景观类型分布更趋均衡化;建筑用地、耕地和林地面积增加,尤其建筑用地面积增加较快,水体和未利用土地的数量减少,水体的斑块数量减少较多。说明银川市在研究时段内各土地利用类型的比例和空间分布格局都有较大变化。     

基于RS与GIS的银川市湿地景观变化研究

应用1991年的TM图像和2006年的ETM图像,将研究区湿地类型分为自然湿地（包括河流湿地、湖泊湿地、灌丛湿地）和人工湿地（包括水塘、输水渠、水产池塘）,提取研究区两个时期的湿地景观,并应用斑块数量、斑块面积、斑块密度、多样性指数、优势度指数、均匀度指数和分维数指数分析了研究区的湿地景观变化情况。结果表明：1991-2006年银川市湿地斑块数量和面积减小幅度很大,但水产池塘的斑块数量与面积呈增加趋势。1991年研究区自然湿地比例远大于人工湿地,但到2006年两种湿地类型比例相当。从景观水平来看,研究区湿地的Shannon多样性指数与均匀度指数减小,优势度指数增加。     

基于IKONOS影像的城市景观格局研究——以银川市开发区为例

选用2001年和2005年的IKONOS遥感图象,应用GIS软件Arcview提取各景观斑块,并计算斑块面积、斑块数量、景观多样性指数、景观优势度指数、景观均匀度指数和景观破碎度数等景观生态指标,对研究区的景观格局进行分析。结果表明:研究区近几年景观格局变化较大,景观的多样性指数和均匀度指数逐渐增加,破碎度指数和优势度指数则呈现减小的趋势。各种景观类型中耕地变化最为明显,斑块面积和斑块数目大幅度减小:居住用地的斑块面积增加较大,道路用地、公共用地和防护林地的面积也有所增加,水域面积有所减小。     

东北平原典型玉米种植区农业景观植物多样性研究——以昌图县为例

非耕作生境是农业景观中的重要组成部分,为生物提供食物和栖息地,对生物多样性保护具有重要意义。本文以辽宁省昌图县为例,选取了20个非耕作生境比例为0~50%的网格(1 km?1 km)为样区,采用典型样地法对调查区域内农业景观中的林地、田间路、草地、沟渠、果园5类主要非耕作生境中的植物群落进行调查,探讨不同非耕作生境类型和比例中植物多样性及其与景观异质性之间的关系。研究结果表明,随着非耕作生境比例增加,植物物种多样性和均匀度先增加后减小,在20%~30%时达到峰值;非耕作生境比例在0~40%范围内时,植物物种丰富度同样呈现先增加后减小,且在20%~30%时达到峰值;非耕作生境比例高于40%时,植物物种丰富度再次出现峰值且高于20%~30%。随着非耕作生境比例的增加,农业景观香浓多样性、香浓均匀度指数和景观斑块形状复杂程度逐渐增加,蔓延度恰好相反。不同生境中重要值最高的均为禾本科植物,但植物种不同;优势种优势度为果园沟渠草地田间路林地。果园、草地和沟渠的物种多样性和均匀度指数显著高于林地和田间路,丰富度指数为草地林地沟渠果园田间路,且草地、果园和田间路的不同调查区域间植物群落指数存在较大的变异性。草地、果园、沟渠、田间路和林地中景观异质性与物种多样性相关性顺次降低。研究结论表明,东北平原典型玉米种植区农业景观中,最适宜非耕作生境比例为20%~30%;非耕作生境中林地、沟渠对物种多样性维持、湿生植物多样性保护具有积极作用;不同生境干扰类型和方式不同,景观异质性与植物物种多样性相关性程度也不同。在今后农业景观生物多样性保护中应综合考虑非耕作生境的类型和比例,干扰的类型和方式等多种因素对生物多样性、生态服务及农业产量的影响。     

兴隆庄采煤对农田景观格局的影响及景观重建

通过对兖州兴隆庄矿区农田在采矿前后、复垦前后的景观格局变化情况的分析，得出如下结论：煤矿区农田在井工开采干扰下，农田景观过程及格局变化取决于采空区的形状、采厚、采深、煤层倾角、地表潜水位和顶板管理方法等，采矿区农田景观格局变化的范围远大于其对应的井工开采对应的采空区范围；采矿条件是影响矿区农田景观格局变化的主要因素，积水、坡地、裂缝是开采后农田景观主要格局；农田景观格局一般随着开采进度的开展，地表逐渐沉陷，由平坦农田转为坡耕地、积水，并且随着开采进度范围逐渐增大，斑块密度减少，斑块面积和斑块周长增加，农田集约程度下降；沉陷农田的景观形状指数较大，形状不规则，斑块形状指数仍然接近1，斑块沉陷边界规则，与区域地下煤层地势平缓相关。     

布尔哈通河流域土地利用格局分析

本研究以景观生态学原理和方法为指导,分析了布尔哈通河干流源头区、中下游河谷区和朝阳河支流3个典型区的景观格局。结果表明,流域面积中有林地最多,占总面积的64.9%,旱地占19.7%,水田占3.6%,草地占3.3%,城镇居民点占2.3%,河渠、水库、沼泽等湿地水体占0.7%;斑块数量以旱田最多,平均斑块面积以有林地最大,斑块面积的变异系数也最大;林业用地中以有林地面积最大,但中下游林业用地比例较上游地区明显减少,其中有林地面积比例急剧减少30个百分点,灌木林地、疏林地和其他林地面积比例较上游增加8个百分点,农田面积中下游较上游地区增加18个百分点;中下游地带斑块数量最多,平均斑块面积和变异系数最小,边界密度最大,景观多样性指数和均匀度指数也较高。     

松嫩平原西部土地整理区景观格局指数的粒度效应研究

以松嫩平原西部大安市土地整理项目区为研究区,基于大安市土地整理前（2008年）1∶10 000土地利用现状图和土地整理后（2014年）项目区1∶10 000土地整理规划设计图,运用GIS技术绘制研究区土地整理景观类型图。运用Fragstats软件分别计算2种不同空间幅度土地整理区整理前后的景观格局指数,选取10个能综合反映土地整理景观格局特征的景观指数,在5～300 m之间的21个粒度范围内分析景观格局指数的粒度效应,并使用数学模型对景观格局指数随粒度增加的变化趋势进行曲线拟合。结果表明:景观格局指数随粒度增加呈现单调上升或下降、先上升后下降和无规律变化3种变化趋势;不同空间幅度下部分景观格局指数粒度效应的转折点存在差异,土地整理前后部分景观格局指数随粒度增加而变化的敏感性不同;斑块数量、斑块密度、最大斑块指数等8个指数能用数学模型很好的拟合,斑块面积方差和Shannon多样性指数拟合效果并不理想,斑块数量、斑块密度、最大斑块指数、斑块面积方差和景观形状指数整理后的拟合效果优于整理前;大安市土地整理项目区景观格局分析的适宜粒度为15～35 m。     

湟水流域近10年土地利用与景观格局演变分析

以青海省湟水流域为研究区,采用中分辨率TM影像和HJ-1卫星CCD数据,利用2000、2005、2010年3个时相的土地利用遥感解译数据,计算了森林、草地、水域、农田、城镇用地和未利用地6个一级分类的土地利用类型转移矩阵,提取了景观格局指数,在此基础上分析了土地利用变化与景观格局的演变特征。结果表明,湟水流域土地利用变化最明显的是农田、城镇用地和草地,其中农田呈持续减少态势,城镇用地和草地呈增加态势;从土地转移矩阵来看,城市扩张带来的建设用地增加是造成流域农田减少的主要原因,而草地的增加主要受益于退耕还林还草和流域生态建设等政策的实施。从景观斑块类型的变化来看,变化最大的是农田和城镇,10年期间,农田在面积减少的同时景观分离度增加,城镇用地在面积增加的同时景观聚集度增加,这说明城镇用地在由中心向外扩张的过程中,空间分布较紧凑且连接性较好;与此同时,草地的斑块个数、斑块密度呈明显减小趋势,而农田与城镇用地的斑块个数、斑块密度总体呈增加趋势,这说明人类活动的不断扩张导致了湟水流域景观破碎度增加。从景观整体水平来看,景观水平指数中边缘密度、形状指数、香农多样性指数、香农平均度指数均呈增加趋势,这说明湟水流域景观结构异质性呈增加趋势。     

成都平原土地利用景观格局变化及驱动因素分析——以成都市龙泉驿区为例

利用GIS技术和景观生态学方法,以成都市龙泉驿区为例,研究成都平原的景观格局变化特征及其驱动因素。研究过程中主要以1996年和2004年土地利用景观格局为基础,采用景观类型面积指数、景观破碎度、景观分离度、景观多样性指数、景观优势度、景观均匀度、景观形状指数分析区域土地利用景观格局变化特点。发现1996-2004八年间,研究区土地利用景观变化剧烈,各景观类型面积比例差异增大,土地利用结构混杂,景观破碎化程度变大,景观形状不规则化程度加剧。区域内部由于自然、经济、社会条件的不同,土地利用景观呈现出不同的特点。分析研究区土地利用景观格局的变化驱动过程,发现人口增长和第三产业发展是导致研究区土地利用景观格局发生变化的重要驱动力;工业化、城镇化、果业和乡村旅游业的发展是另一主要驱动力。     

Phytotoxicity of cobalt,vanadium, titanium,silver, and chromium

Abstract

The phytotoxicity of five nonessential elements (Co, V, Ti, Ag, Cr) to higher plants was studied in solution culture experiments with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen). All, but in varying degrees, tended to concentrate in roots with a decreasing gradient to stems and leaves. Cobalt was one of the more mobile of the five trace metals. Its toxicity was expressed as severe chlorosis; 43 (with 10^‐5 M) and 142 (with 10^‐4 M) μg Co/g dry weight in leaves resulted in severe chlorosis. Vanadium as 10^‐4 M vanadate resulted in smaller plants but not in chlorosis. Leaf, stem, and root V, respectively, were 13, 8, and 881 μg/g dry weight. Titanium was somewhat mobile with considerable yield decrease at 10^‐4 M; leaf, stem, and root Ti concentrations, respectively, were 202, 48, and 2420 μg/g. Symptoms were chlorosis, necrotic spots on leaves, and stunting. Silver was very lethal at 10^‐4 M AgNO₃; at 10^‐5 M yields were greatly decreased, but plants were grown without symptoms. Leaf, stem, and root concentrations of Ag for this treatment, respectively, were 5.8, 5.1, and 1760 μg/g dry weight. Plants grown with 10^‐5 N Cr₂O₇ were decreased in yield by about 25% with or without EDTA (ethylenediamine tetraacetic acid) while the same level of Cr₂(SO₄)₃ was essentially without effect. For the two salts, the leaf, stem, root concentrations for Cr, respectively were 2.2 and 1.3, 0.7 and 0. 7, and 140 and 104 μg/g. Most of the trace metals studied here had interactions in the uptake and/or distribution of other elements.     

Bioavailability of As,Cd, Co,Cr, Cu,Hg, Mo,Ni, Pb,Se, and Zn from Biosolids Amended Compost

Appropriate compost standards are being considered in Canada. Five aspects of compost safety and quality are being evaluated; probably the most controversial aspect is the standards for metals in compost. In order to assist in the development of appropriate standards, the authors began an extensive research project in October, 1993 to determine the bioavailability of metals from compost and compost-metal mixtures. Swiss chard was grown in compost-amended soils or compost in a growth room using five treatments of increasing percentages of compost in the media (0, 25 percent, 50 percent, 75 percent, 100 percent compost (v/v)). A Truro loamy sand and a race-track manure-biosolids compost (RTM-biosolids) supplemented with a high metal biosolids were used in a completely randomized design with five replicates. Dry matter yield, metal content in plant tissue, and total metal uptake were evaluated as well as the total and DTPA-extractable metal content in the compost-soil mixes. The results of this and five other experiments conducted by the authors will help determine whether the suggested limits for As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se and Zn in composts are appropriate.     

Variation of N,P, K,Ca, Mg,Mn, Zn,and al in slash pine foliage

Abstract

The seasonal patterns of foliage nutrient concentrations and contents were monitored for two growing seasons in an 11‐year—old Pinus el1iottii stand. In the first growing season after needle initiation, N, P, K, Mg, and Zn concentrations decreased, but this was followed by an increase in the fall and winter months. Another drop in concentration of all elements, except P, occurred in the second growing season. Decreases in total contents indicated that this drop was a result of translocation to other tissues. In contrast to the mobile elements, the concentration and fascicle contents of Ca, Mn, and Al increased with aging of the needles.

Between‐tree variability was least for N, P, and Zn and the N, K, Mg, Mn, and Zn in the current foliage had consistently lower variation than that in the 1‐year‐old foliage. Between‐tree variation for K was lower in the winter than the spring.

For pine foliage, recommended sampling period for N, P, Mg, and Zn is mid to late summer and for the other elements it is late fall to late winter.

There are several sources of variation that influence the level of nutrients in tree foliage. The most important of these, apart from the tree nutrient status, are seasonal fluctuations, variation between trees, and age of needles . Smaller sources of variation are associated with position of the needles within the crown, diurnal changes, year to year variation, and analytical errors^1,2. These variables must be studied in order to develop suitable sampling techniques and in Pinus this has been undertaken for P. banksiana ¹, P. taeda ³, P. strobus ⁴, P. resinosa ⁴, P. sylvestris ⁵, and P. radiata ^6,7. However, foliage sampling has not been studied in detail for slash pine (Pinus elliottii Englem var. elliottii) and earlier studies with other pines have been largely confined to temperate or cool climates.

This study reports the variation in elemental concentrations with season, age of foliage, and between slash pine trees growing in a subtropical climate in Florida.     

Cooking,Roasting, and Fermentation of Chickpeas,Lentils, Peas,and Soybeans for Fortification of Leavened Bread

The effects of cooking, roasting, and fermentation on the composition and protein properties of grain legumes and the characteristics of dough and bread incorporated with legume flours were determined to identify an appropriate pretreatment. Oligosaccharide content of legumes was reduced by 76.2–96.9% by fermentation, 44.0–64.0% by roasting, and 28.4–70.1% by cooking. Cooking and roasting decreased protein solubility but improved in vitro protein digestibility. Mixograph absorption of wheat and legume flour blends increased from 50–52% for raw legumes to 68–76, 62–64, and 74–80% for cooked, roasted, and fermented ones, respectively. Bread dough with cooked or roasted legume flour was less sticky than that with raw or fermented legume flour. Loaf volume of bread baked from wheat and raw or roasted legume flour blends with or without gluten addition was consistently highest for chickpeas, less for peas and lentils, and lowest for soybeans. Roasted legume flour exhibited more appealing aroma and greater loaf volume of bread than cooked legume flour, and it appears to be the most appropriate preprocessing method for incorporation into bread.     

Thin layer chromatographic determination of aflatoxins, ochratoxins, sterigmatocystin, zearalenone, citrinin, T-2 toxin, diacetoxyscirpenol, penicillic acid, patulin, and penitrem A.

A general method is described for determining 16 mycotoxins in mixed feeds and other food products used in the manufacture of these feedstuffs. The mycotoxins are extracted and cleaned up by extracting with solvents of different pH. Thin layer chromatography is used to separate the toxins; toxins are then quantitated by the limit detection method. The minimum detectable concentration of mycotoxins in various products is: aflatoxin B1 or G1, 4--5 micrograms/kg; ochratoxin A or ethyl ester A 140--145 micrograms/kg; citrinin 600--750 micrograms/kg; zearalenone, 410--500 micrograms/kg; sterigmatocystin, 140--145 micrograms/kg; diacetoxyscirpenol, 2400--2600 micrograms/kg; T-2 toxin, 800--950 micrograms/kg; patulin, 750--800 micrograms/kg; penitrem A 14,000--14,500 micrograms/kg; penicillic acid 3400--3650 micrograms/kg.     

Estimation of Reference Values for Cadmium,Cobalt, Chromium,Copper, Nickel,Lead, and Zinc in Brazilian Soils

Abstract

The objectives of this study were 1) to recommend reference values (RVs) and tolerance limits (TLs) for representative Brazilian soils and 2) to propose a model to calculate natural contents of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in a soil from the silt, clay, manganese (Mn), iron (Fe), and cation exchange capacity (CEC) values. A set of 256 soil samples was classified by similarity in seven groups, and the concentrations corresponding to the upper quarter of data collected were then calculated. These concentrations are proposed as RVs for Brazilian soils. Additionally, TLs were obtained for each group from the antilog expression (m+2s), where m=mean value and s=standard deviation of data transformed in log₁₀. The classification functions of discriminant analysis proved to be suitable to allocate new samples in the established groups. Thus, it is possible to evaluate soils under anthropic activity and, by comparison with reference values, to be aware of pollution risks in a given area.     

Glucoraphanin and 4-hydroxyglucobrassicin contents in seeds of 59 cultivars of broccoli, raab, kohlrabi, radish, cauliflower, brussels sprouts, kale, and cabbage

The importance of dietary sulforaphane in helping maintain good health continues to gain support within the health-care community and awareness among U.S. consumers. In addition to the traditional avenue for obtaining sulforaphane, namely, the consumption of appropriate cruciferous vegetables, other consumer products containing added glucoraphanin, the natural precursor to sulforaphane, are now appearing in the United States. Crucifer seeds are a likely source for obtaining glucoraphanin, owing to a higher concentration of glucoraphanin and the relative ease of processing seeds as compared to vegetative parts. Seeds of several commonly consumed crucifers were analyzed not only for glucoraphanin but also for components that might have negative health implications, such as certain indole-containing glucosinolates and erucic acid-containing lipids. Glucoraphanin, 4-hydroxyglucobrassicin, other glucosinolates, and lipid erucic acid were quantified in seeds of 33 commercially available cultivars of broccoli, 4 cultivars each of kohlrabi, radish, cauliflower, Brussels sprouts, kale, and cabbage, and 2 cultivars of raab.     

Distribution of Zinc,Manganese, Copper,Cobalt, and Nickel in Andosols Profiles

The distribution of zinc, manganese, copper, cobalt, and nickel in Andosols was investigated. Sixty nine soil samples were collected from different horizons of an Andosols profile in Miyakonojo Basin in south Kyushu, Japan, The total contents of heavy metals were determined by digestion and four extraction solutions, 1 M NH₄Ac (ammonium acetate) pH 4.5, 0.1 M HCl, 0.01 M EDTA (ethylenediaminetetraacetic acid) pH 6.5, and 0.005 M DTPA (diethylenetri-aminepentaacetic acid) pH 7.3 were used to determine the contents of available Zn, Mn, Cu, Co, and Ni in Andosols in relation to the organic carbon content. The results of the extraction analysis showed that by the use of 0.1 M H Cl high value of extracted heavy metals in the upper layers of the humus horizons were obtained while EDTA extraction yielded a large amount of the above mentioned metals in the high humus horizons. The extractable heavy metals contents were high and these metals closely related to the organic carbon content mostly in the humus horizons in the profile. Where, biocycling process may play an important role in the concentration of heavy metals. Based on the study, it was found that the total content of Zn increased towards the C horizons or pumice layers in the soil profile. Such a trend was also found in the case of the Mn content. While the Cu content in the humus horizons was much higher in the upper part of each humus horizon. According to this study the distribution of heavy metals, Cu (organic matter complexes) in the Andosols profile was more stable than that of Zn (organic matter complexes) in soils. It was shown that Zn in the surface humus horizon was enriched but that some amount was leached under buried conditions. The same phenomenon was also observed in the distribution of Mn in the profile. The movement of Co and Ni in the soil profile was limited, as evidenced by the sharp reduction in the concentrations of these two metals in buried soils.

Hence, it is concluded that the distribution of Zn, Mn, Cu, Co, and Ni was considerably higher in the humus horizons of the Andosols profiles.     

Fluxes of Cu,Zn, Pb,Cd, Cr,and Ni in temperate forest ecosystems

The literature on the fluxes of six heavy metals in temperate forest ecosystems is reviewed. Special attention is given to wet and dry deposition and internal flux, to metal budgets for ecosystems and soils, to concentrations in aqueous compartments of the ecosystem and to speciation in soil solutions. Metal fluxes are discussed in relation to pollution load, soil type, tree species and land use. The mobility of Cu and Pb is strongly dependent on the solubility of organic matter. These metals are commonly accumulated in forest soils. Zinc, Cd and Ni are greatly influenced by soil acidity and are often lost in considerable amounts from acidified soils. Chromium is often at balance in forest ecosystems. Implications for metal solubility and budgets in forest soils are discussed in connection with an increase in soil acidification.     

Evaluation of Decomposition Procedure to Determine Ba,Co, Cr,Cu, Ni,Mn, V,and Zn Total Content in Soil Samples

Different procedures have been proposed to decompose soil samples. Most of them regard determination with fertility aims. In this case, the contents available to the plants are considered. On the other hand, there are procedures to determine total content. The objective of this work was to propose a new decomposition procedure to determine barium (Ba), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), vanadium (V), and zinc (Zn) total content in tropical soils with high content of oxides and silicate. According to the results, the digestion procedure proposed in this study provided satisfactory results for the contents recovery for the elements Ba, Co, Cr, Cu, Mn, Ni, V, and Zn, above 90%, and the use of inverted aqua regia, hydrogen peroxide (H₂O₂), hydrofluoric acid (HF), pre-digestions and agitation was shown as a new alternative for the high silicate content soil sample total digestion, such as the oxisols.