Passar para o conteúdo principal

page search

Displaying 4045 - 4056 of 5230

Comparison of Soil Bacterial Communities Under Diverse Agricultural Land Management and Crop Production Practices

Journal Articles & Books
Dezembro, 2008

The composition and structure of bacterial communities were examined in soil subjected to a range of diverse agricultural land management and crop production practices. Length heterogeneity polymerase chain reaction (LH-PCR) of bacterial DNA extracted from soil was used to generate amplicon profiles that were analyzed with univariate and multivariate statistical methods. Five land management programs were initiated in July 2000: conventional, organic, continuous removal of vegetation (disk fallow), undisturbed (weed fallow), and bahiagrass pasture (Paspalum notatum var Argentine).

[Bulletin of Agrarian Science of the Cis-Black Sea Region]

Policy Papers & Briefs
Dezembro, 2008
Ucrânia

The present e-collection of scientific works deals with results of research on issues of economy, agrarian and engineering sciences studied by researchers, post-graduate students, magisters and students of Mykolayiv State Agrarian Univ. and other educational establishments of the Ministry of Agrarian Policy of Ukraine are elucidated. The issue comprises 30 scientific papers, distributed by three sections, in particular Economic sciences (18 papers), Agricultural sciences (10) and Engineering sciences (2 papers), and, what is important, except the Ukrainian-language contents (pp.

Associations Between Weevils (Coleoptera: Curculionidea) and Plants, and Conservation Values in Two Tussock Grasslands, Otago, New Zealand

Journal Articles & Books
Dezembro, 2006
Nova Zelândia

Ecosystem level processes and species interactions have become important concepts in conservation and land management. Despite being New Zealand’s greatest contributors to global diversity, native invertebrates have been largely overlooked in the assessment of land values, and their diversity has often been assumed to reflect native plant diversity without justification. Invertebrates can in fact affect plant species composition, and in ecosystems such as New Zealand’s remaining indigenous and semi-modified tussock grasslands can do so in excess of more conspicuous vertebrate grazers.

Fine-particle emission potential from overflowing areas of the Tarim River

Journal Articles & Books
Dezembro, 2013
China

Fine particulates less than 2.5 μm (PM2.5) or 10 μm (PM10) are often emitted from river bank or other alluvial lands to the atmosphere during dry and windy seasons worldwide, which contribute to land degradation and poor air quality. Investigation of PM2.5 and PM10 emission potential could contribute to the development of mitigation strategy and better land management practices. In the lowprecipitation zone (

Assessing plant protection practices using pressure indicator and toxicity risk indicators: analysis of therelationship between these indicators for improved risk management, application in viticulture

Journal Articles & Books
Dezembro, 2015
França

The excessive use of plant protection products (PPPs) has given rise to issues of public and environmental health because of their toxicity. Reducing the use of toxic PPPs and replacing them with products that are less toxic for human health and the environment have become socially, environmentally and economically indispensable.

CO₂ fluxes and evaporation on a peatland in the Netherlands appear not affected by water table fluctuations

Journal Articles & Books
Dezembro, 2009
Países Baixos

The effect of shallow water table fluctuations on the evaporation and CO₂ fluxes in a peatland is investigated. The fluxes of evaporation and net ecosystem exchange of carbon were measured from mid-spring to the end of summer in 2005 and 2006 and simulated independently with process models. The observed and modelled data were then compared along a gradient of water levels. Any variation along the gradient would imply an influence of the water table on the flux. It became evident that changes in the water table had no effect on the evaporation and CO₂ fluxes of the peatland.

Key variables for the identification of soil management classes in the aeolian landscapes of north–west Europe

Journal Articles & Books
Dezembro, 2013
Europa

At present, spatially very detailed data sets can be obtained about soil, landscape and crop variability. However, there is a need to select independent key properties to identify management classes needed for precise land management. In a previous study performed in the European loess belt, topsoil pH, apparent electrical conductivity (ECa) and elevation were identified as key properties. In this study we enlarged the number of soil properties by including gamma ray measurements and employed a similar methodology to a field in the sand belt of northern Europe.

Management Submodel of the Wind Erosion Prediction System

Journal Articles & Books
Dezembro, 2013

This article describes the WEPS management submodel component which simulates the effects of typical cropping management practices, such as tillage, planting, harvesting, irrigation, or residue burning, at an operational level. Such management practices can affect the surface conditions, which in turn affect wind erosion potential. A variety of land management operations is simulated by identifying the primary physical processes involved and representing each individual operation as a sequenced set of those processes.

Nitrogen losses in runoff from three adjacent agricultural watersheds with claypan soils

Journal Articles & Books
Dezembro, 2006
Estados Unidos

Despite improvements in the use of soil conservation practices, crop rotation and managed fertilizer applications, large losses of nitrogen (N) in runoff continue to occur from row-cropped watersheds. Increasing requirements for implementing water quality standards in the United States, has increased pressure for the development of research-based guidelines to reduce N losses from agricultural runoff.

Twenty-five years of changes in soil cover on Canadian Chernozemic (Mollisol) soils, and the impact on the risk of soil degradation

Journal Articles & Books
Dezembro, 2012

Huffman, T., Coote, D. R. and Green, M. 2012. Twenty-five years of changes in soil cover on Canadian Chernozemic (Mollisol) soils, and the impact on the risk of soil degradation. Can. J. Soil Sci. 92: 471–479. Agricultural soils that are covered by vegetation or crop residue are less susceptible to degradation by wind and water erosion, organic matter depletion, structural degradation and declining fertility.