Mixing calcium chloride with commercial fungicide formulations results in very slow penetration of calcium into apple fruits

Foliar applications of calcium salts are usually combined with fungicides. In the years 2002 and 2003, it was tested if this practice assures high rates of penetration of calcium. Amounts that penetrated in 24 h were measured at 20 °C using ⁴⁵CaCl₂. To ensure maximum penetration rates, humidity was maintained at 100 %. Sample size was 40 to 50 fruits, and data were presented as box plots because distribution of data was not normal. Median rates of penetration of CaCl₂, measured with mixtures of fungicides and CaCl₂ at 5 or 10 g l^–1, respectively, were very slow, and amounted to only a few percent of the dose applied. Rates were a little higher with very young fruits (55 days after full bloom, DAFB). Adding alkyl polyglycoside surfactants at 0.2 g l^–1 significantly decreased surface tensions, and increased rates of penetration by up to 15‐fold. Still, total penetration of CaCl₂ rarely exceeded 20 % of the dose applied (median penetration), even in the presence of an additional surfactant. In all treatments, outliers with 60 to 100 % penetration in 24 h occurred, and this was attributed to penetration into lenticels. This is expected to result in unequal concentrations of calcium in fruits, especially in the sub‐epidermal layers. Addition of a suitable surfactant to mixtures of fungicides with CaCl₂ is strongly recommended as it enhances wetting and greatly increases penetration rates of CaCl₂.     

Mechanisms of cuticular uptake of xenobiotics into living plants: evaluation of a logistic-kinetic penetration model

The objective of this study was to determine whether a logistic-kinetic penetration model could be applied to whole plant uptake. Uptake over 24 h was determined for three model compounds, applied in the presence and absence of surfactants, into the leaves of two plant species. Data for two time intervals were used in the model to predict uptake at intermediate intervals and compared with experimental results. Overall, the model fit the whole plant uptake data well. The study confirmed that an increase (or decrease) in active ingredient (ai) concentration or an increase in contact area will have no effect on the penetration rate factor, q, within the normal working concentration range. This enabled uptake to be predicted at different times for concentrations of ai not already studied, having first derived q for one concentration of the formulation of interest and having 24 h (maximum) uptake results for all formulations and concentrations of interest. The advantages of the models and equations described are that few variables are required, and they are simple to measure.     

Direct determination of potassium-calcium activity ratio in soils with two ion-selective electrodes. II. Interactions of potassium and calcium ions with soils

The interactions of potassium and calcium ions with two variable charge soils and one constant charge soil were examined by measuring the pK-0.5pCa value with two ion-selective electrodes, together with measurements of single ion activities. The constant charge soil showed a much higher preference for calcium relative to potassium than the variable charge soils. The relative affinities of potassium, calcium, sodium and aluminum ions with exchange sites were not constant, but were a function of surface properties of the soil. pH affected the pK-0.5pCa value in both the variable charge soil and the constant charge soil. The strong competition of aluminum ions for exchange sites was the major cause of the higher preference of soils for calcium ions relative to potassium ions at low pH. The pK-0.5pCa value was always smaller in sulfate systems than in chloride systems, with the difference more distinct in variable charge soils. In addition to an initial fast reaction, some potassium ions were immobilized at later times, even for the highly weathered variable charge soil.     

Detection of allergenic ingredients using real-time PCR: a case study on hazelnut (Corylus avellena) and soy (Glycine max)

Compliance with the European allergen labeling legislation (Directive 2007/68/EC) is only possible when coupled with appropriate methods to detect allergens in food. The aim of the current study was to develop new real-time PCR assays for the detection of hazelnut and soy and evaluate these assays via comparison with commercially available kits. Although the new assays were not as sensitive as the commercial qualitative assays, they proved to be more specific. Moreover, the cross-reactivity study indicated contamination of some of the food products used with either hazelnut or soy, which presents a risk for the allergic consumer. The assays were able to quantify as few as 5-15 genome copies. This unit, used to express analytical results for allergen detection by means of PCR, needs to be converted to a unit expressing the amount of allergenic ingredient in order to be informative. This study emphasizes that the use of real-time PCR for allergen quantification is complicated by the lack of appropriate reference materials for allergens.     

Coupling proton transfer reaction-mass spectrometry with linear discriminant analysis: a case study

Proton transfer reaction-mass spectrometry (PTR-MS) measurements on single intact strawberry fruits were combined with an appropriate data analysis based on compression of spectrometric data followed by class modeling. In a first experiment 8 of 9 different strawberry varieties measured on the third to fourth day after harvest could be successfully distinguished by linear discriminant analysis (LDA) on PTR-MS spectra compressed by discriminant partial least squares (dPLS). In a second experiment two varieties were investigated as to whether different growing conditions (open field, tunnel), location, and/or harvesting time can affect the proposed classification method. Internal cross-validation gives 27 successes of 28 tests for the 9 varieties experiment and 100% for the 2 clones experiment (30 samples). For one clone, present in both experiments, the models developed for one experiment were successfully tested with the homogeneous independent data of the other with success rates of 100% (3 of 3) and 93% (14 of 15), respectively. This is an indication that the proposed combination of PTR-MS with discriminant analysis and class modeling provides a new and valuable tool for product classification in agroindustrial applications.     

Lysimeter study with a cambic Arenosol exposed to artificial acid rain: I. Concentrations of ions in leachate

The effects of artificial acid rain on soil leachate composition were studied in a lysimeter experiment. Cambic Arenosol (Typic Udipsamment) in monolith lysimeters was treated for 6 1/2 yr with 125 mm yr^?1 artificial rain in addition to natural precipitation. Artificial acid rain was produced from groundwater with H₂SO₄ added. pH levels of 6.1, 4 and 3 were used. Increasing content of H₂SO₄ in the artificial rain increased the concentration of Ca²⁺ and Mg²⁺ in the leachate significantly. The pH of the leachate was slightly reduced only by the most acidic treatment (pH 3). The H^+? retention was not accompanied by a proportionate increase in the Al ion concentration. A slight increase in the Al ion concentration was only observed in the leachate from the pH 3-treated lysimeter. We conclud that cation exchange and/or weathering were the main buffer mechanisms in the soil. The study supports conclusions from other acidification studies, that acidic precipitation is likely to increase the leaching of Ca²⁺ and Mg²⁺ from soils.     

Effectiveness of crop straws,and swine manure in ameliorating acidic red soils: a laboratory study

Purpose

Crop straws and animal manure have the potential to ameliorate acidic soils, but their effectiveness and the mechanisms involved are not fully understood. The aim of this study was to evaluate the effectiveness of two crop (maize and soybean) straws, swine manure, and their application rates on acidity changes in acidic red soils (Ferralic Cambisol) differing in initial pH.

Materials and methods

Two red soils were collected after 21 years of the (1) no fertilization history (CK soil, pH 5.46) and (2) receiving annual chemical nitrogen (N) fertilization (N soil, pH 4.18). The soils were incubated for 105 days at 25 °C after amending the crop straws or manure at 0, 5, 10, 20, and 40 g kg^?1 (w/w), and examined for changes in pH, exchangeable acidity, N mineralization, and speciation in 2 M KCl extract as ammonium (NH₄⁺) and nitrate plus nitrite (NO₃^??+?NO₂^?).

Results and discussion

All three organic materials significantly decreased soil acidity (dominated by aluminum) as the application rate increased. Soybean straw was as effective (sometimes more effective) as swine manure in raising pH in both soils. Soybean straw and swine manure both significantly reduced exchangeable acidity at amendment rate as low as 10 g kg^?1 in the highly acidic N soil, but swine manure was more effective in reducing the total acidity especially exchangeable aluminum (e.g., in the N soil from initial 5.79 to 0.50 cmol₍₊₎ kg^?1 compared to 2.82 and 4.19 cmol₍₊₎ kg^?1 by soybean straw and maize straw, respectively). Maize straw was less effective than soybean straw in affecting soil pH and the acidity. The exchangeable aluminum decreased at a rate of 4.48 cmol₍₊₎ kg^?1 per pH unit increase for both straws compared to 6.25 cmol₍₊₎ kg^?1 per pH unit from the manure. The NO₃^??+?NO₂^? concentration in soil increased significantly for swine manure amendment, but decreased markedly for straw treatments. The high C/N ratio in the straws led to N immobilization and pH increase.

Conclusions

While swine manure continues to be effective for ameliorating soil acidity, crop straw amendment has also shown a good potential to ameliorate the acidity of the red soil. Thus, after harvest, straws should preferably not be removed from the field, but mixed with the soil to decelerate acidification. The long-term effect of straw return on soil acidity management warrants further determination under field conditions.

     

Within-site habitat configuration in reserve design: A case study with a peatland bird

This study assesses the effects of considering within-site habitat configuration when designing reserve networks. This attribute takes all its importance in situations where the long-term integrity of (within-site) habitat patches cannot be preserved without protecting their surrounding environment. We addressed this issue through the concrete problem of selecting a reserve network of natural peatlands in southern Québec, Canada. We used a reserve-selection algorithm that minimized the total number of peatlands to include within networks. The algorithm was constrained to include peatlands containing habitat patches that met specific size thresholds. Five habitat-clustering thresholds were used to set the eligibility of each site to the selection process. The resulting reserve networks were evaluated according to their representation efficiency and to the expected consequences for the Palm Warbler (Dendroica palmarum), an area and isolation-sensitive bird restricted to peatlands in southern Québec.Constraining the algorithm to include peatlands showing increasingly larger patches of habitats led to larger networks, both in terms of area and number of sites, and to networks composed of smaller sites. These effects increased with the representation target (i.e., the % of each habitat preserved). With respect to the Palm Warbler, selecting peatlands with larger patches of habitats had only an indirect effect on its site-occupancy pattern. Indeed, despite the fact that the probability of occurrence of the warbler was negatively correlated with the size of habitat patches, the habitat-clustering threshold influenced the incidence of the warbler mainly via its effect on the physical attributes of the selected networks - including the area, isolation level, and the number of selected sites. Because increasing the habitat-clustering threshold led indirectly to a greater regional availability of prime breeding habitats for the Palm Warbler, it mitigated the severe negative impact of an hypothetical alteration or destruction of non-selected peatlands. Our study thus emphasizes the importance of determining how the different factors describing within-site configuration are correlated with other intrinsic characteristics of the sites available to the selection process before opting for a site-selection strategy.     

Isomerization of lactose-derived oligosaccharides: a case study using sodium aluminate

Galactooligosaccharides (GOS) obtained during the enzymatic hydrolysis of lactose contain large amounts of glucose, galactose, and unreacted lactose, which do not have prebiotic properties and increase the calorific value of the product. In this work, the isomerization of the GOS mixture by the action of sodium aluminate has been studied. During the reaction, lactose, glucose, and galactose were isomerized to lactulose, fructose, and tagatose, respectively, and in addition allolactose, 6-galactobiose, and 6'-galactosyl-lactose were also converted to the corresponding keto-sugars. The effect of time, temperature, and aluminate/initial lactose ratio has been studied. After 9 h at 40 degrees C and molar ratio aluminate/lactose 3:1, the isomerization yield was >60%, and the amount of final carbohydrates was close to 90% of the initial product. This process considerably decreases the amount of lactose, glucose, and galactose.     

Mechanism of interaction of Pb(II) with milk proteins: a case study of alpha-casein

Alpha-casein is the major casein protein fraction from bovine milk and is responsible for binding to many ligands. This paper reports the results on the interaction of Pb(II) with alpha-casein. The interaction studies by spectroscopic titration indicate that Pb(II) has two binding sites with an association constant (ka) of (2.3 +/- 0.2) x 10 (5) M(-1). Raman spectra of the alpha-casein-Pb(II) complex show reduction in the amide I region as well as minor perturbations in the sulfhydryl region of alpha-casein. Stopped-flow studies show that the reaction mechanism of Pb(II) follows a pseudo-first-order reaction with a rate of 25 +/- 6 s(-1). The stopped-flow time-resolved spectra show peaks at 330 and 360 nm, correlating to Pb(II)-thiolate bands in the UV absorption spectra. Modification of cysteines present in alpha-casein does not result in binding of lead, indicating that cysteines could be one of the Pb(II) binding sites.     

土地整理分区研究——以北京市大兴区为例

在各级土地整理专项规划中，为明确区域土地整理的类型与方向，制订适合实际情况的土地整理标准，进而为土地整理潜力评价提供基础，需进行土地整理分区。该文以北京市大兴区为例，以乡镇为分区单元，采用经济社会指标与自然指标相关延伸的方法，确定10项指标进行星座聚类分析，将大兴区分成北部经济发达区、东部产粮区与中南部综合发展区三个区，并分别明确了三个区域土地整理的方向。     

土地整理分区研究--以北京市大兴区为例

在各级土地整理专项规划中,为明确区域土地整理的类型与方向,制订适合实际情况的土地整理标准,进而为土地整理潜力评价提供基础,需进行土地整理分区.该文以北京市大兴区为例,以乡镇为分区单元,采用经济社会指标与自然指标相关延伸的方法,确定10项指标进行星座聚类分析,将大兴区分成北部经济发达区、东部产粮区与中南部综合发展区三个区,并分别明确了三个区域土地整理的方向.     

Infant mortality and soil type: a case study in south-central England (with discussion)

We have analysed the differences in infant mortality for 1981 to 1990 in areas of contrasting soil types in south-central England. The soils overlie rocks of varied lithology and hydrology, ranging from porous and permeable Chalk and limestones, to the generally wet and impermeable Oxford and Lower Jurassic Clays. The study area comprises 504 administrative wards, for each of which the soil has been classified as being predominantly‘Wet’, ‘ Intermediate’ or ‘Dry’, depending on the degree of seasonal or periodic waterlogging. The soil classes used are those mapped by the Soil Survey of England and Wales and relate closely to the underlying geology. We find proportionately more infant deaths on the‘Wet’ soils, and a gradation towards lower infant mortality rates on the drier soils. Overall, infant mortality on the‘Wet’ soils is 31·9 percent greater than on the‘Dry’ soils, for reasons that remain unexplained. This relation between infant mortality and soil moisture remains after the effect of social class has been removed.     

Beyond parks and reserves: The ethics and politics of conservation with a case study from Perú

This paper elaborates, analyzes, and partly defends the normative and empirical foundations of a “social ecology” model for natural habitat and resource management. This model treats human societies as being irreducibly integrated with the natural systems in which they are embedded. It argues that any concept of biodiversity necessarily embodies cultural values for it to be operationalized for conservation decisions. It accepts the legitimacy of tradeoffs between biodiversity conservation and other values including human resource development. It prioritizes local control of decisions in regions which are often targeted by Northern conservationists: areas of the South, where cultural choices have led to the persistence of high biodiversity. This model is used to analyze an ongoing dispute over biodiversity conservation and natural resource control in Perú: the conflict over Kandozi territory in the Abanico del Pastaza. What the Kandozi want is more than just a rejection of what has been criticized as the national park/fortress model of conservation. It consists of an assertion of local institutionalized control over traditional lands which goes well beyond the purview of the usual alternative of the fortress model: the biosphere reserve model of external and internal joint control of natural resources. To the remarkable extent that Kandozi resource management practices have succeeded in maintaining biotic richness and variety in spite of multiple encroachments, the empirical evidence demands that today’s conservationists pay adequate attention to these practices and the social institutions in which they are embedded. But, beyond such prudential concerns, the social ecology model of habitat conservation accepts the normative claims that resident communities should have control over their lands and livelihoods and that they should be allowed to maintain their habitats as cultural landscapes of their choice.     

Interaction of naphthalene derivatives with soil: an experimental and theoretical case study

This study provides insight into the relevance of the chemical functional groups of soil organic matter (aromatic, paraffinic, O‐alkyl, carboxyl and carbonyl carbon), as determined by CPMAS ¹³C NMR, on adsorption processes. Batch adsorption experiments with eight naphthalene derivatives were conducted with soils from a long‐term field experiment and model sorbents. Although the adsorption of some derivatives was mainly affected by the paraffinic organic carbon content in soil, the relation between the C‐distribution and adsorption was complex. This casts doubt on the use of such NMR data to estimate sorption behaviour. Additionally, sorption experiments were performed with six model sorbents representing typical soil components. Considerable adsorption of naphthalene derivatives was observed for montmorillonite and lignin; the smallest values were for kaolinite and cellulose. A quantum chemical approach was used to calculate a local polarity parameter as a molecular property of the naphthalene derivatives. This parameter was correlated with the logarithm of the adsorption coefficients, logK_d. Here, clear trends were observed for three of the model sorbents (kaolinite, montmorillonite and lignin).     

A study of spatial variability of soil loss with high resolution DEMs: A case study of a sloping olive grove in southern Spain

Land degradation worldwide over several centuries has become a serious problem. This phenomenon has been accentuated in agricultural areas, where the amount of topsoil loss creates a gradual loss of farmland productivity. Ploughing is responsible for tillage erosion which causes more soil movement than natural soil creepage. In fact sediment transport is more rapid using heavy machinery than with primitive ploughs. The main aim of our research is to monitor, in detail, the sediment deposition phenomenon of eroded soil. Here the role of high resolution DEMs is essential. We develop a DEM generated from field measurements taken by GPS. The high spatial density of these measurements allows us to generate DEMs of high resolution: cell sizes of 0.5, 1 and 1.5 m. Three zones of different area are used in order to analyse the scale effects. In this study we assess precise models that represent a soil redistribution phenomenon.     

Improving the detection of agricultural drought: a case study of illinois corn production

Too little attention has been given to the manner in which drought detection and monitoring indices are applied in agricultural settings. In this research, results of an Illinois corn-weather sensitivity analysis were used to select values of the moisture anomaly index (MAI or z) and related Palmer drought severity index (PDSI or X) to match periods of maximum moisture (i.e., drought) sensitivity in the corn growing season. These partial growing season values were compared with their equivalent growing season average for 12 Illinois sites to evaluate which were most effective in explaining interannual variations in detrended corn yields. Results indicate that the Palmer indices calculated for only the peak corn moisture sensitivity periods, outperformed the mean growing season Palmer indices in accounting for 1960–1983 interannual variations in corn yields by a factor of more than two.     

Updating digital soil maps with new data: a case study of soil organic matter in Jiangsu,China

The rapid developments in the acquisition of data on soil should enable pedologists to update existing digital soil maps readily. The methods by which that is done must take into account temporal change in soil properties and local differences in spatial variation. The common mapping techniques will have to be modified to make full use of digital data. We show what can be achieved with a case study on updating maps of soil organic matter (SOM) in Jiangsu Province, China, with three sets of soil data collected in the 1980s, 2000 and 2006. Our results showed that temporal changes in SOM between the three sampling periods occurred in only very small parts of the regions. Models of spatial variation of SOM based on the data collected in the 1980s and 2006 for the whole region differed somewhat, whereas models based on the data collected in the 1980s, 2000 and 2006 for the Taihu region (south Jiangsu) were significantly different. As updating with Bayesian maximum entropy continued, the accuracy of prediction increased and that of the prediction variance decreased. Finally, our study leads us to suggest improved technologies for updating digital soil maps with new data.     

Strong effects of a plantation with Pinus patula on Andean subpáramo vegetation: a case study from Colombia

The effect of a pine plantation on a native subpáramo system in the Andes of Colombia (3100 m above sea level) was studied. The vegetation of an 8 year-old plantation with Pinus patula was compared to that of the surrounding native subpáramo. 59 plots made in the subpáramo vegetation contained 121 vascular plant species. These plots were classified into three subpáramo communities and one Andean scrub community. Sixty-four plots made in the pine plantation contained 76 vascular plant species and were subdivided into four classes of pine cover. With increasing pine cover, pine plantation plots tended to become less similar to the subpáramo communities. Habitat-specific subpáramo species tended to disappear with increasing pine cover. After controlling for the effects of environmental variables in a partial canonical correspondence analysis, pine cover had a significant impact on plant species patterns. It is concluded that afforestation with Pinus patula resulted in strong negative effects on diversity and composition of the subpáramo vegetation at the study site.     

Soil erosion in Guizhou province of China: a case study in Bijie prefecture

Abstract. Guizhou province has one of the most severe soil erosion problems in China, with 44% of its total area affected. Within the province, Bijie prefecture is the most severely eroded with 63% of the total area affected. In recent decades this erosion is mainly caused by man's agricultural and industrial development. Not only is erosion restricting crop production, it is the cause of disastrous floods which recur with a frequency far greater than in the past. Reduced infiltration of rain has led to a third of the wells and a fifth of the streams running dry, depriving people and livestock of drinking water.
This unsustainable use of land can only be corrected by a combination of population control, prevention of slash and burn cultivation and return of steeply sloping land to forest and grassland. Greater appreciation of the need for soil and water conservation is an essential part of this process.