نتایج جستجو برای: agricultural fields

تعداد نتایج: 342254  

2014
Yufeng Luo Haolong Fu Seydou Traore

Rice paddies are artificial wetlands that supply people with food and provide wildlife with habitats, breeding areas, shelters, feeding grounds and other services, and rice paddies play an important part in agricultural ecological systems. However, modern agricultural practices with large-scale intensive farming have significantly accelerated the homogenization of the paddy field ecosystem. Mod...

Journal: :Ecological applications : a publication of the Ecological Society of America 2006
Kendra K McLauchlan Sarah E Hobbie Wilfred M Post

Soil organic matter (SOM) often increases when agricultural fields are converted to perennial vegetation, yet decadal scale rates and the mechanisms that underlie SOM accumulation are not clear. We measured SOM accumulation and changes in soil properties on a replicated chronosequence of former agricultural fields in the midwestern United States that spanned 40 years after perennial-grassland e...

Journal: :Environmental science & technology 2006
Shelie A Miller Amy E Landis Thomas L Theis

Intensive agricultural systems are largely responsible for the increase in global reactive nitrogen compounds, which are associated with significant environmental impacts. The nitrogen cycle in agricultural systems is complex and highly variable, which complicates characterization in environmental assessments. Appropriately representing nitrogen inputs into an ecosystem is essential to better u...

2011
Eric B. Schneider

This paper employs multiple regression analysis to evaluate the effectiveness of yieldraising techniques available to medieval farm managers (reeves) using a panel dataset of 49 manors held by the Bishop of Winchester from 1349-70. There are three main interesting findings. First, annual weather variation, modelled with climate reconstructions, was highly significant in explaining annual yield ...

2013
Guo-Chun Ding Yvette M. Piceno Holger Heuer Nicole Weinert Anja B. Dohrmann Angel Carrillo Gary L. Andersen Thelma Castellanos Christoph C. Tebbe Kornelia Smalla

Natural scrublands in semi-arid deserts are increasingly being converted into fields. This results in losses of characteristic flora and fauna, and may also affect microbial diversity. In the present study, the long-term effect (50 years) of such a transition on soil bacterial communities was explored at two sites typical of semi-arid deserts. Comparisons were made between soil samples from alf...

Journal: :Environmental Health Perspectives 2002
Denise Koch Chensheng Lu Jennifer Fisker-Andersen Lance Jolley Richard A Fenske

We measured organophosphorus (OP) pesticide exposures of young children living in an agricultural community over an entire year and evaluated the impact of agricultural spraying on exposure. We also examined the roles of age, sex, parental occupation, and residential proximity to fields. We recruited 44 children (2-5 years old) through a Women, Infants, and Children clinic. We collected urine s...

2012
JOHN M. PLEASANTS KAREN S. OBERHAUSER

1. The size of the Mexican overwintering population of monarch butterflies has decreased over the last decade. Approximately half of these butterflies come from the U.S. Midwest where larvae feed on common milkweed. There has been a large decline in milkweed in agricultural fields in the Midwest over the last decade. This loss is coincident with the increased use of glyphosate herbicide in conj...

2012
Jahangeer A. Bhat Munesh Kumar Bhupendra Singh

The present study was carried out to assess the effect of leaf and bark aqueous extract of Anogeissus latifolia tree on Vigna unguiculata traditional crop to understand the suitability of treecrop combination in agricultural fields. Different concentrations of leaf (1%, 3% and 5%) and bark (1%, 3% and 5%) aqueous extract of A. latifolia were used to study radicle and plumule growth of V. unguic...

Journal: :CoRR 2017
Andres Milioto Philipp Lottes Cyrill Stachniss

Precision farming robots, which target to reduce the amount of herbicides that need to be brought out in the fields, must have the ability to identify crops and weeds in real time to trigger weeding actions. In this paper, we address the problem of CNN-based semantic segmentation of crop fields separating sugar beet plants, weeds, and background solely based on RGB data. We propose a CNN that e...

2015
Olivier Samson-Robert Geneviève Labrie Pierre-Luc Mercier Madeleine Chagnon Nicolas Derome Valérie Fournier

While honey bee exposure to systemic insecticides has received much attention, impacts on wild pollinators have not been as widely studied. Neonicotinoids have been shown to increase acetylcholinesterase (AChE) activity in honey bees at sublethal doses. High AChE levels may therefore act as a biomarker of exposure to neonicotinoids. This two-year study focused on establishing whether bumble bee...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید