Arable Land Plots Research Articles

Process decomposition of expanded rural housing at the rural–urban fringe: evidence from 27,034 buildings in Pudong New Area, Shanghai, China

PurposeFaced with the challenges of rural population decline, combined with the widespread expansion of homesteads in rural areas, local Chinese governments hope to strictly control and minimize rural housing land. Accurately decomposing the process of rural housing expansion and revealing its driving factors will be helpful for land-use regulation by the government.Design/methodology/approachIn this study, an unusually rich dataset of rural housing registration from Pudong New Area in Shanghai is employed. The study aimed to decompose the fragmented accumulation process and its expansion determinants on rural housing assets. The dataset covers all samples of rural households and housing plots at 72 surveyed villages in six towns.FindingsHousing offers profitable capital and earning assets to villagers at the urban fringe, so they have a powerful incentive to build and expand more. The results of this analysis showed that the expansion of rural housing is largely due to the haphazard construction of auxiliary rooms by villagers, especially on plots of arable land that are adjacent to their houses that have been stealthily converted into auxiliary rooms and sheds. Low costs and weak penalties have led to an increase in rent-seeking expansions to rural houses. Houses with the smaller initial areas, families with more laborers and household heads, and the proximity of villages to downtown with convenient living services were the main driving factors for expanding houses. A concerted effort is needed to control the disorganized and unlicensed expansion of housing. This effort should include formulating areas for free use by villagers, high taxes on overused areas, serious penalties for unlicensed housing expansion and effective land-use planning.Research limitations/implicationsAn understanding of the expansion status and control measures related to rural houses in Shanghai provides an important reference that can help to guide the formulation of rural housing policies, and the sustainable development of cities worldwide. Of course, this study cannot generalize about housing distribution and expansion status worldwide based on the study area in China, because China's land tenure policies are unique. But land registry data exists that makes research like this feasible. There is a need to carefully examine the detailed housing distribution in each country before it can be decided on how best to address the disorderly increase in rural housing stock, and promote the reduction of rural residential expansion.Originality/valueFirst, the process of rural housing expansion by using an unique dataset which covers ten thousands of samples is revealed. Second, the results have policy implications for reducing the amount of idle and inefficiently rural homestead. The focus is on rural housing growth and its driving factors in Shanghai, and the villagers' motivations for housing expansion are explored.

Determination of the shelterbelts influence on the average productivity of agrophytocenoses based on geostatistical analysis of spatial data and the NDVI

Shelterbelts effect positively on the elements of the microclimate, the water regime of soils, the agronomic properties of the soil, soil fertility in the agricultural landscape. The assessment of the influence of the density of shelterbelts on the overall productivity of arable land is poorly studied. In this study, the methodology for assessing of such impact with using GIS technologies is suggested. We propose to use the Normalized Vegetation Index (NDVI), as a standardized index showing the relative biomass of vegetation, averaged for each working area within the studied region for working plots of arable land with an area of more than 25 hectares in the Belgorod oblast. Paired correlation analysis between the density of shelterbelts and arable land productivity showed the weak relationship (R2= 0.124), however, the classification of the density of shelterbelts with the interval of 0.5 km/km2 allowed us to reveal the linear regression dependence y = 0.0059x + 0.5195 (R2 = 0.989) of arable land productivity from the density of shelterbelts. Taking into account that many abiotic factors can affect the yield, we additionally proposed to carry out typing to identify areas of the same type in terms of the relief of the earth’s surface, climatic conditions and productivity. To do this, the spatial clustering (K-means algorithm) was proposed to use. It was revealed that the productivity of agrophytocenoses increases by 10% with the increasing of the density of shelterbelts by 2 times with an average slope steepness of up to 2°. In physical terms, the yield of winter wheat will increase by 0.28 t/ha. Soil-protective crop rotations are an additional factor in increasing the value of the NDVI index on slopes more than 2°.

Geoinformation Methodology of Agricultural Land Evaluation for Agricultural Economic Growth

The formation of an economically developed management system for the country's agro-industrial complex cannot be considered only from the point of view of a separate science. Land resources are the source of profit, which is involved in almost all sectors of society. Land preservation and improvement is required to ensure an economic security and competitiveness of each region of the Russian Federation). The dynamics of changes in the areas of Svetloyarsky district of the Volgograd region in the context of municipalities is analyzed. The actual deviation of the area of Privolzhsky rural settlement amounts to 2,3 % of the statistical data. The boundaries and areas of the used plots of arable land in the Raigorod settlement do not coincide with the data of the state cadastral registration, the discrepancy of only one land plot is 422,44 hectares. By implementing GIS-technologies, the data were obtained for 2355 arable land plots, whereof the irrigated land area amounts to 52138 hectares, instead of the potentially possible 19455 hectares, that exceeds the settlement's capabilities by 2,7 times according to the statistical data.

Features of water regime changes of steppe chernozem in the South-East of Central Chernozem zone in modern conditions

The article presents an analysis of the elements of the water regime of the steppe chernozems of the Stone Steppe of the Central Chernozem Region in the conditions of the dry period from the end of 2019 to the autumn of 2020. The objects of the study were: the mowed fallow land plowing in 1882, the old-growth forest strip of 1903 planting and arable land adjacent to fallow plots. The soil-hydrological constants were calculated (total water capacity, lowest field capacity, permanent wilting point) both in the time interval and down the soil profile to a depth of 2 m. The reserves of productive moisture during the growing season were also studied. The maximum values of productive moisture content was reached on the mowed fallow sites by the beginning of February, the minimum in the forest belt areas, the arable land plots had an intermediate value. By the middle of the growing season (June), 2020, the moisture reserves in the soils of the forest strip, fallow and arable land were 127, 123 and 109 mm, respectively, in the meter thickness. The highest amount of productive moisture in the upper soil horizon (0-20 cm) is observed under the forest belt – 39 mm. However, moisture content under the fallow land in the upper horizon had decreased to rate of the dead moisture reserve by early August. Similar values were found in soil under the forest belt and arable land. Otherwise, moisture profile was formed in underlying carbonate horizons. The forest belt soils in insufficient atmospheric moisture conditions in 2020 were more dried out than soil of fallow and arable land. The estimation was given for nature of soil profile changes of soil moisture profile due to influence of forest belt. The data of productive moisture reserves in soil at different distances from the forest belt were presented. In the meter layer at the edge of the forest belt, moisture reserves were at the level of 94.0 mm, sharply decreasing to 60.3 mm at a distance of 25 m from the forest strip, with a gradual decrease to 34 mm at a distance of 125 m. The results of observations showed a clear downward trend of productive moisture content due to distance from the old-growth forest belt.

The development and implementation of programs for the use and protection of agricultural lands in the regional projects for the development of agriculture and agricultural clusters, and state regulation of agricultural lands fertility

Land legislation - the Land Code of the Russian Federation, the Federal Law " Land Management", the Federal Law "Turnover of Agricultural Lands", the Federal Law "State Regulation of Agricultural Lands Fertility" proclaimed the obligation of state authorities, local governments, legal entities and individuals realize their activities with preservation of land as the most important component of the environment and a natural resource, and carry out measures for the reproduction of the fertility of agricultural lands. There are proclamations, but no effective economic, administrative mechanisms and institutions of enforcement to save productive land and soil fertility. Regulations for the environmentally safe use of separately cultivated plots of arable land, contours of hayfields and pastures with spatial identification of the boundaries of their action on the map for land management have not been established – we can see negative impacts of excessive cultivation of arable land. The proposed measures to ensure the fertility of agricultural lands are aimed not at land use with soil-saving agricultural technologies in the process of agricultural activities when growing crops (in accordance with the established regulations), but at restoration of soil fertility after depletion of agricultural land use through reclamation and other measures for agrochemical services. This article proposes to restore the compulsory land management activities in case of identification of lands with water and wind erosion and other negative impacts with the development of regulations for environmentally safe agricultural land use for each field or part of it, the contour of hayfields and pastures exposed to negative impacts of anthropogenic or natural load. It is easier to prevent than to cure.

Картографический анализ компонентов агроландшафта при формировании устойчивого землепользования в условиях деградации земель Волгоградской области

Modern geoinformation studies of the structural components of the agricultural landscape allow us to quickly assess the state, the degree of preservation and the impact of its individual elements on the environment, and the sustainability of each land use. The preservation of the quality of land resources is the most important task for agricultural production and socio-economic development of the region. Mapping of the test site “Catchment area of the Kasarka River” made it possible to determine the agricultural landscape as a typical one, with an area of 78.55 thousand square meters. ha, with a predominance of arable land—60.3 %, woodlands—11.3 % and protective forest strips of artificial origin—3.6 %. The remaining area—19.39 thousand hectares—is occupied by hayfields and pastures, lands of settlements, roads and allotments. The terrain features a height difference of 86 m and a maximum slope angle of 7.5°. 456 plots of arable land were surveyed, the system of protective forest stands includes 581 forest strips and 21 forest stands, with a total area of 11.75 thousand hectares. 74.3 % of forest strips and massifs are degraded, the share of fallen forest belts was 34.3 %, the effectiveness of the protective action of forest stands is only 67 %, and this does not ensure the integrity of the agricultural landscape. The dependence of the slope angle (X) on the value of the potential washout (M) was determined, which made it possible to calculate the soil washout for each plot of arable land, which varies from 4.8 t/ha to 34.7 t/ha. The total flushing of the soil at the maximum values of the slope angles of the test site will be 823750.3 tons. For individual test plots of arable land, the spread of the calculated value of the average nutrient flushing is also significant from 3.1 t (test plot P67, area 0.943 ha), to 1655.5 t (test plot H142, area 296.86 ha).

К вопросу учета орошаемых угодий Волгоградской области с применением методов дистанционного мониторинга

Purpose: justification of the need for irrigated lands inventory and their allocation into a separate category as the main component of the agricultural landscape that forms the ecological stability and sustainability of agricultural production. Materials and methods. The research was carried out within the boundaries of Svetloyarsk district Volgograd region. The object of research is a semi-desert zone of light chestnut soils. The research was carried out using aerospace observation methods in combination with geoinformation technologies and computer modeling. As a result of computer processing and transformation of space photographs, an overview space photomap of the research region is created, on which a coordinate grid, boundaries and additional attributive information are plotted. For geoinformation analysis and implementation of data processing, the QGIS 3.12 software package was used. The images were obtained from the Sentinel-2, Landsat-8 or Landsat-7 satellites, and they make it possible to carry out the whole complex of studies related to obtaining information on the state of agricultural land. Results. The location, boundaries and actual use of 2355 plots of arable land have been determined, of which 1424 are irrigated. The features of each specific site, namely the area, minimum and maximum slope angles, elevation differences and other characteristics have been determined, which made it possible to determine the suitability of these sites for irrigation purposes more accurately. Conclusions. Clarification of the nature and intensity of the use of land plots, of which more than 60 % are irrigated, requires their detailed inventory and tracking of ongoing changes. The maximum (1071 hectares) and minimum (0.7 hectares) areas of irrigated areas, the maximum slope angle of 8.18 grade, the vertical drop up to 131 m and the configuration characterize the course of erosion processes during irrigation. The discrepancy in the areas within the boundaries of Raygorodsky rural settlement was 148.26 hectares, which reflects the real picture of the irrigated lands use and availability.

Soil modification in a chronosequence of postagricultural ecosystems of the intrazonal lithogenic matrix (Arkhangelsk region, Russia)

Processes of soil self-restoration and soil modification in the chronosequence of postagricultural ecosystems located within the intrazonal (floodplain) soils of boreal forests were studied. Successional changes in ecological features of the floodplain meadow soil properties in the postagricultural period were considered. We used arable land plots (22 model fields) in the Northern Dvina River delta (Primorsky District, Arkhangelsk region, Northwestern Russia) that have been removed from agricultural practice for the past 50 years and are currently at the self-overgrowing stage. Primary/secondary floodplain meadows with natural floodplain soils were used as reference plots. Changes in soil profiles and chemical properties in an old-arable horizon were observed during the restoration of abandoned fields. Floodplain soils of the Northern Dvina River basin occupied 4.8% of the area. These soils were characterized by high fertility and were actively used in agricultural production in the past. Postagricultural ecosystems of the Northern Dvina River floodplain tended to form natural waterlogged soils to varying extents. Ecosystems were characterized by a short period of soil restoration. The soil restoration process was slower than the vegetation cover restoration process. Soil fertility of the arable horizon persisted for 20 years. A cost-effective return of floodplain meadow lands to agricultural production is feasible over a period of 40 years. Then, soils return to natural floodplain soils, whereby they become waterlogged and lose their fertility.

Requirements for multispectral remote sensing data used for the detection of arable land colonization by tree and shrubbery vegetation

We discuss requirements for the multispectral remote sensing (RS) data utilized in the author's technique for estimating plant species concentration to detect arable land colonization by tree and shrubbery vegetation. The study is carried out using available high-resolution remote sensing data of two arable land plots. The paper considers the influence of resolution, combinations of spectral channels of RS data, as well as the season RS data is acquired on the quality of identification of elementary vegetation classes that form the basis of the plant community – a fallow land. A fallow land represents a piece of arable land that has not been cultivated for a long time. The study was conducted using a technology that is based on image superpixel segmentation. We found out that for determining tree and shrub vegetation, it is preferable to use RS data acquired in autumn, namely, in late September. The combination of red and blue spectral channels turned out to be the best for the analysis of tree-shrub vegetation against the background of grassy plant communities, and the presence of a near-infrared channel is necessary to range the various grassy plant communities in different classes. RS data with a spatial resolution of 2.5 m can be used to define tree-shrub plant communities with a high closeness of crowns (90 % or more), but cannot be used to classify isolated trees. Trees and shrubs (with a height of 8 m) can be classified in images with a spatial resolution of 0.8 m. An increase in spatial resolution does not improve the quality of the classification. The highest accuracies achieved for the land areas studied are 90 % and 83 %. Therefore, the suggested technology can be used in arable land expertise.

Структурный состав почв юго-востока Центрально-Черноземной зоны с различным характером использования (на примере почв Каменной степи)

The study of the structural state of chernozems with patterns of use was done at V.V. Dokuchaev Research Institute of Agriculture of the Central Black-Earth Zone in 2019. The study was done under the conditions of agrocenoses and undisturbed ecosystems. Soils of naturally preserved biocenosis were represented by ordinary chernozems (automorphic) or segregation chernozems, soils of arable land – ordinary chernozems (automorphic) or segregation agro-chernozems. The experimental plots of arable land with slope variants were represented by sections of slopes of the Eastern exposure with a slope of up to 3°. The soil cover of experimental arable plots was a combination of chernozems such as topsoil segregation, migration-micellar with a small part of zoogenic turbocharged soil. The soil structure was determined by the method of N.I. Savvinov. A significant reduction in the share of agronomically valuable aggregates in soils influenced to intensive agrogenic impacts was found. Confirmation of this phenomenon was a significant decrease of the coefficient of soil structure: 3.2 on arable land, 14.0 – on abandoned land. There was a threefold decrease in the amount of the soil aggregates under the conditions of agrogenic impacts in spite of there was the small amount of silty part of the soil aggregates. The meso-aggregates of soil with size from 2 to 5 mm were related to the most vulnerable component of soil agronomically valuable structure. There were the most noticeable decrease of the relative content of meso-aggregates of soil under agricultural impacts (along with lumpy particles).

Impacts of Intensive Agriculture on Current Rural Landscape - A Case Study for South Moravian Landscape, Czech Republic

The landscape in several countries of Central and Eastern Europe went through the most dramatic change in the socialist period. Agricultural land was considered only as a productive area. The size of arable land plots increased and stabilizing elements in the landscape were removed. This land consolidation of agriculture has led to the development of soil erosion. This paper presents a case study focused on comparison of landscape structure of model territory in two periods. The first period shows landscape before collectivization of agriculture, and the second one presents current landscape. The research dealt especially with evaluation of ecological stability and water erosion risk of the landscape. The identification of land use trends helps to characterize landscape of the model territory during monitored period. The following trends: decreasing area of arable land, increasing area of built‑up areas and other areas and increase area of vineyards showed different character of current landscape. The evaluation of ecological stability confirmed the loss of stable landscape elements. Based on the calculated values of ecological stability coefficient, the evaluated landscape has degraded from the category of “disturbed landscape capable of self‑regulation” to “devastated landscape”. The results also show the vulnerability of current large plots of arable land and vineyards to water erosion.

Seasonal and Long-Term Features of the Distribution of the Vegetation Index NDVI on Arable Lands in Bryansk Region

The features of the multi-year distribution of vegetation indices are considered as an indicator of the favorable conditions for farming, the correspondence of the set of crops with the soil, geomorphological, microclimatic characteristics of the agrolandscape. The authors presented methodical problems of using information about NDVI for remote determination and monitoring of soil properties through bioproductivity. Methods of collecting and systematizing information on the seasonal and long-term dynamics of NDVI (according to MODIS data) and some factors of the spatial distribution of its mean values were used for a detailed study of the issue. The possible mechanisms of influence of the surface slope (the values are determined by SRTM), the average humus content, the mechanical strength of soils on the NDVI distribution were shown. Information on NDVI arable land changes in the Bryansk region in the years with different meteorological conditions (2010-2015) was given. The general features of NDVI seasonal dynamics within the vegetation period were described – from late March to early November. The influence of meteorological factors on the distribution of NDVI was determined. Synchronous differences in the dynamics of NDVI for groups of arable land plots homogeneous in the state of the surface slope and agrotechnical characteristics of soils were justified from the position of seasonal dynamics of landscapes. A complex ratio of the significance of groups of factors was shown, possible models for explaining their differences in space and time were proposed.

Estimation of Environmental Sustainability of the Landscape of the Basin Western Bug Rivers In Volyn Region

Purpose. Determination of ecological stability of landscapes of the basin of the Western Bug River and its tributaries in Volyn region. Methods. Comparative-geographical, analytical, generalization, systematization, calculation of ecological stability of the landscape on the basis of the method of E. Clementova, V. Heinig. Results. The calculation of the quantitative assessment of the ecological stability of the landscapes in the basins of the Western Bug tributaries revealed that the KESL1 index of the Pischadka, Neretva and the Zolotoha River ranges from 1.3 to 1.6. That making basin landscapes conditionally stable. River Studyanka and Luga range from 0,027 to 0,026, which testifies them to the unstable structure of the landscapes of the basin with pronounced instability. It is established that in the landscapes of the basin of the Western Bug River of Volyn Region, their ecologically balanced structure is predominant at the KESL1 1.04 index. This is due to the structure of the lands of the basin, where agricultural (arable land) cause a big loading and destabilized landscapes occupies in most of the area. The largest plots of arable land occupy the sub basins of the rivers Studyanka and Luga, and the smallest ones in the sub basins of the Neretva, Zolotukha and Gapa rivers, which is due to the significant forested areas of the basin. The qualitative assessment of ecological stability of the landscape is characterized by the coefficient of ecological stability of the biotechnical elements of the entire landscape of the K ESL2. Calculations of KESL2 showed that the landscape structure of the basin of the Western Bug River in the Volyn region is slightly stable and the index is 0.48. The KESL2 coefficients of the Studyanka and Lug lakes are 0.21 and 0.23 respectively, and characterize them as unstable geosystems. The structure of the landscapes of the basins of the Peschadka and Kopayevka rivers for KESL2 - (0,95 - 0,67) is stable. Consequently, intensive settlement of land, drainage of marshes, deforestation violated the integrity of landscapes led to their denaturalization. Particularly significant changes occurred in the southern part of the basin. Conclusions. As a result of the calculations of the quantitative assessment of the ecological stability of landscapes (KESL1), the landscapes of the basin of the Western Bug River in the Volyn region are conditionally stable. And according to the indicators of qualitative assessment of ecological stability of the landscape (KESL2), they are characterized as low-static geosystems. In general, determining the stability of the landscape is important for assessing the ecological situation of the basin of the Western Bug River, since it fully reflects the overall ecological status of the river basin.

Ancient agriculture and paleographic characteristics of the Ubsunurskaya depression

Natural regularities were revealed in the development of irrigated agriculture in ancient Tuva, suggesting that the region of Central Asia was home to an ancient agricultural civilization. The study identified ample evidence of ancient irrigation on desert landscapes of the Ubsunurskaya depression, large plots of arable land exceeding considerably the areas of today’s agriculture. It was established that the irrigation systems along the valley of the Tes-Khem river show abundant evidence of ancient settlements. Arid territories of Central Asia–regions of traditional animal husbandry are considered. A town of ancient farmers, hitherto virtually unknown to science, was discovered on the western shore of Lake Ubsu-Nur. Remnants of irrigation systems were investigated, and it was found that separate plots of land were concentrated on low-level peatbogs which were good arable lands. Paleobotanical analysis of peatbogs and buried soil horizons determined the character of vegetation cover on the study territory, pointing to a stable development of vegetation of the foreststeppe type in the past. Wheat and millet grains were discovered, which confirm the existence of agriculture in these areas. Macroremains of forest and forest-steppe vegetation suggest that at the time of ancient agriculture there occurred plant communities on desert landscapes of the Ubsunurskaya depression. It is established that deforestation was among the reasons behind the desertification of this territory.

An explanation of labor migration and grain output growth: Findings of a case study in eastern Tibetan Plateau

Although there has been rapid rural-urban migration in rural China since the 1980s, the total grain production of China saw a continuous increase. As of today, the relationship between labor migration and grain output growth remains partial and contradictory. The main aim of this empirical study is to examine some specific measures adopted by peasants to deal with labor shortage and maintain grain output growth. Using tracking survey, participatory rural appraisal methods, and land plot investigation, we investigate 274 households and 1405 arable land plots in four villages in two stages in Jinchuan county, southwestern China. The results show that continuous emigration of labor from the four villages caused the abandonment of a small amount of land, decreased labor intensity, and reduced multiple cropping index, shifting from “corn-wheat” multiple cropping pattern to the “corn” cropping pattern, which means labor shortage in some households. At the same time, owing to surplus labor in the villages, the peasants utilize a series of means to offset the negative impacts of labor migration on grain output, such as cropland transfer, labor exchange in the busy seasons, and the substitution of capital and technology for labor. The econometric analysis also shows that labor migration boosts grain production. This study provides a reasonable explanation of grain output growth under rural-urban migration.

Indirect nitrogen losses of managed soils contributing to greenhouse emissions of agricultural areas in Austria: results from lysimeter studies

A considerable share of greenhouse gas emissions, especially N2O, is caused by agriculture, part of which can be attributed to indirect soil emissions via leaching and runoff. Countries have to report their annual emissions, which are usually calculated by using the default value of 0.3 for FracLEACH, a factor that represents the fraction of nitrogen losses compared to total nitrogen inputs and sources. In our study we used 22 lysimeters, covering a wide range of soils, climatic conditions and management practices in Austria, to evaluate nitrogen losses through leaching and to calculate FracLEACH. The terms of the nitrogen mass balance of the lysimeters were directly measured for several years. Both grassland and arable land plots gave significantly smaller values of FracLEACH than the default value. For grassland, FracLEACH values of only 0.02 were found which varied very little over the entire observation period. For arable sites, FracLEACH values were higher (around 0.25) and showed significant variability between years due to variations in crop rotation, fertilization rates, and yields.

Identification of areas with significant flood risk at the confluence of Danube and Ipeľ rivers (southern Slovakia)

The village of Chľaba is located in the southwest Slovakia, bordered with the fork of Danube River and Ipeľ River and in the southeast foothill of Burda Mts. This creates a specific rural environment of a Slovak–Hungarian border area. Ministry of Environment of the Slovak republic did not include this village in the list of potential significant flood risk areas, despite the fact that during the time of extraordinary floods, the village of Chľaba is completely separated from the only functional access road. This leads to great damages on arable land plots in the inundation area and consequently to a significant soil erosion. This phenomenon takes place in the area of huge parcels, which are characterized by intensive agriculture activities and harvests. In the paper, we tried to identify the range of the flood affected areas during the time of extraordinary floods (June 2013) and to propose flood protection arrangements within the landscape utilization changes in affected areas. The article presents the resulting map of the sloped and under-flooding areas, based not only on a terrain identification by conventional methods of field research, but also on a comparison of real slopped areas in 2013 with prognostic flood hazard map and flood risk map created by the Danube Floodrisk project. In the conclusion, we propose landscape utilization changes, which could lead to more effective human activities applications in the cadastral territory of the Chľaba village. This attitude might reduce the negative impact of floods in the researched endangered territory.

How to model species responses along ecological gradients – Huisman–Olff–Fresco models revisited

AbstractQuestionsIn species response modelling, can a hierarchical logistic regression framework compete against GAM in terms of statistical inference? Are bimodal shapes useful to model species responses along ecological gradients?LocationGermany.MethodsIn hierarchical logistic regression modelling [also known as Huisman, Olff, Fresco (HOF) models], the best model is chosen from a set of predetermined models using statistical information criteria, i.e. a balance between model fit to the data and simplicity of the model. We extended the classical five model types with two bimodal shapes. We improved the model optimization process to inhibit unrealistically steep slopes and abrupt changes. The stability of model choices is safeguarded through bootstrapping. The framework was tested on a data set of 547 vegetation plots of arable land with measured soil pHKCL. The ability to reproduce known shapes was tested with artificial data sets. Shape parameters, e.g. niche width and range, slope (turnover) and species optima, can be calculated from the models and used for further analyses. The model framework together with advanced plot functions is included in the package eHOF for the statistical software environment R.ResultsBased on the AIC, 66 out of 131 species are modelled with a better compromise between model fit and model complexity by one of the logistic regression models as compared to GAM with automatic smoother selection. Within the model framework, 17 species (13%) are best modelled with one of the new bimodal types. The test with artificial data of known shape reveals good reliability of eHOF models for unimodal responses in areas with homogeneous information, but increasing uncertainty if the sampling is uneven or if only a part of the response is covered within the observed gradient range.ConclusionsHierarchical logistic regression models offer a flexible way to efficiently fit species response data. They propose a sound theoretical background for ecological interpretation. Extended HOF models as presented here are judged as an effective tool for univariate species response modelling.

Quantitative detection and diversity of the pyrrolnitrin biosynthetic locus in soil under different treatments

The prevalence of antibiotic production loci in soil is a key issue of current research aimed to unravel the mechanisms underlying the suppressiveness of soil to plant pathogens. Pyrrolnitrin (PRN) is a key antibiotic involved in the suppression of a range of phytopathogenic fungi. Therefore, field soils from different agricultural regimes, including permanent grassland, arable land under common agricultural rotation and arable land under maize monoculture, were investigated in respect of the prevalence of pyrrolnitrin biosynthetic loci. Primers for detection of the prnD gene were used for initial PCR/hybridisation-based assessments. By this method, evidence was obtained for the contention that PRN production loci were most prevalent in grasslands, however, robust quantitative data were not achieved. To quantify the prevalence of PRN biosynthetic loci, we designed a TaqMan PCR system based on the prnD gene for the real-time quantitative detection of this production locus in soil. The system was found to be specific for prnD sequences from Pseudomonas, Serratia and Burkholderia species. Using pure culture DNA, the prnD gene was detectable down to a level of 60 fg, or approximately 10 gene copies, per amplification reaction. Application of the system to soil DNA spiked with different levels of the target DNA indicated that, in a soil DNA background, specific amplification could be obtained to about the same level of sensitivity. Field soil samples obtained from the different agricultural regimes were then screened for the prevalence of prnD with the real-time PCR system. The quantitative data obtained suggested a strongly enhanced presence of prnD genes in grassland or grassland-derived plots, as compared to the prevalence of this biosynthetic locus in the arable land plots. The implications of these findings are placed in the context of the suppressiveness of soil to phytopathogens, notably Rhizoctonia solani AG3.

Jews in the Tropics: Bahian Jews in the Early Twentieth Century

A monarchy based on the slave plantation labor of Africans until the late nineteenth century, vast Brazil offered little appeal to European immigrants except in the far south of the country, where smaller plots of arable land became available as the coffee frontier expanded. Facing shortages in slave supply after mid-century, when the British forced the Brazilians to end the trans-Atlantic slave trade, provincial governments attempted to lure European immigrants by granting subsidies to pay for transport and for initial costs of settlements. In 1881, the Imperial government joined in the effort to recruit immigrants who, in addition to providing a replenished work force, could also be counted on to “whiten” the population. Germans predominated among immigrants until 1886, followed by Italians, Poles, and some Japanese until the 1930's, when rising xenophobia led Brazilian officials to curtail immigration and to install a restrictive quota system.