251 research outputs found
The school counselor, sexual abuse, and R.E.T.
One in four girls and one in ten boys are sexually molested before they are eighteen years old (Cohen & Phelps, 1985; Harrison, 1985; Kempe & Kempe, 1984). The perpetrator of sexual abuse is usually someone the child knows (Adams & Fay, 1981). The father, stepfather or long-time live in boyfriend is the perpetrator in approximately one half of the cases (Cohen & Phelps, 1985; England & Thompson, 1988; Tharinger & Vevier, 1987)
Cover crops grown in monoculture and mixed cropping affect soils differently
Cover crops provide various benefits to agricultural soils. The legumes among cover crops may provide fixed nitrogen as nutrient. Other species show high uptake and storage capacity for nitrogen, thus preventing losses as water polluting nitrate or greenhouse effective nitrous oxide. The input of carbon by shoot and root biomass, as well as rhizodeposition and root decay after harvest or mulching increases soil quality e.g. in form of nutrient supply and organic matter buildup. Brassicaceae lack mutualism with mycorrhizal fungi and some species can reduce the number of phytopathogenic nematodes, thus affecting food web structures. However, many benefits provided by single plant species may be affected when these species grow under mixed cropping. In a pot experiment ten typical cover crop species were grown in monoculture: Phacelia tanacetifolia, Brassica rapa var. rapa, Raphanus sativus var. oleiformis, Sinapis alba, Trifolium incarnatum, Vicia villosa, Avena strigosa, Lolium multiforum, Sorghum bicolor x S. sudanense, and Fagopyrum esculentum. These were compared to six mixtures ranging in complexity from two to six species including the classics R. sativus/S. alba, R. sativus/A. strigosa, and the “Landsberger Gemenge”. Six plants per pot grew in two differently textured soils (silty loam, loamy sand) in a greenhouse for 60 days. Plant parameters measured, included shoot and root dry matter, their C and N content, root morphology, plant height as well as chlorophyll content. In the soil, the pH, C-to-N-ratio, inorganic nitrogen, microbial biomass, and abundance of microbial domains were measured. Already plant parameters indicated effects caused by mixed cropping. Height and chlorophyll content of P. tanacetifolia, S. alba, and S. bicolor were higher in monocultures than in mixtures indicating interspecific competition. Furthermore, below-ground biomass of two-species-mixtures containing R. sativus appeared to be higher than those of the corresponding monocultures. While monocultures increased soil pH differently, mixtures showed no significant difference between each other. This study aims to show that the impact on soil by different cover crop species are not necessarily realised the same way under mixed cropping
a review
It is well documented that global warming is unequivocal. Dairy production
systems are considered as important sources of greenhouse gas emissions;
however, little is known about the sensitivity and vulnerability of these
production systems themselves to climate warming. This review brings different
aspects of dairy cow production in Central Europe into focus, with a holistic
approach to emphasize potential future consequences and challenges arising
from climate change. With the current understanding of the effects of climate
change, it is expected that yield of forage per hectare will be influenced
positively, whereas quality will mainly depend on water availability and soil
characteristics. Thus, the botanical composition of future grassland should
include species that are able to withstand the changing conditions (e.g.
lucerne and bird's foot trefoil). Changes in nutrient concentration of forage
plants, elevated heat loads and altered feeding patterns of animals may
influence rumen physiology. Several promising nutritional strategies are
available to lower potential negative impacts of climate change on dairy cow
nutrition and performance. Adjustment of feeding and drinking regimes, diet
composition and additive supplementation can contribute to the maintenance of
adequate dairy cow nutrition and performance. Provision of adequate shade and
cooling will reduce the direct effects of heat stress. As estimated genetic
parameters are promising, heat stress tolerance as a functional trait may be
included into breeding programmes. Indirect effects of global warming on the
health and welfare of animals seem to be more complicated and thus are less
predictable. As the epidemiology of certain gastrointestinal nematodes and
liver fluke is favourably influenced by increased temperature and humidity,
relations between climate change and disease dynamics should be followed
closely. Under current conditions, climate change associated economic impacts
are estimated to be neutral if some form of adaptation is integrated.
Therefore, it is essential to establish and adopt mitigation strategies
covering available tools from management, nutrition, health and plant and
animal breeding to cope with the future consequences of climate change on
dairy farming
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Biochar as a tool to reduce the agricultural greenhouse-gas burden–knowns, unknowns and future research needs
Agriculture and land use change has significantly increased atmospheric emissions of the non-CO2 green-house gases (GHG) nitrous oxide (N2O) and methane (CH4). Since human nutritional and bioenergy needs continue to increase, at a shrinking global land area for production, novel land management strategies are required that reduce the GHG footprint per unit of yield. Here we review the potential of biochar to reduce N2O and CH4 emissions from agricultural practices including potential mechanisms behind observed effects. Furthermore, we investigate alternative uses of biochar in agricultural land management that may significantly reduce the GHG-emissions-per-unit-of-product footprint, such as (i) pyrolysis of manures as hygienic alternative to direct soil application, (ii) using biochar as fertilizer carrier matrix for underfoot fertilization, biochar use (iii) as composting additive or (iv) as feed additive in animal husbandry or for manure treatment. We conclude that the largest future research needs lay in conducting life-cycle GHG assessments when using biochar as an on-farm management tool for nutrient-rich biomass waste streams. © 2017 The Author(s) Published by VGTU Press and Informa UK Limited, [trading as Taylor & Francis Group]
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Biochar research activities and their relation to development and environmental quality. A meta-analysis
Biochar is the solid product that results from pyrolysis of organic materials. Its addition to highly weathered soils changes physico-chemical soil properties, improves soil functions and enhances crop yields. Highly weathered soils are typical of humid tropics where agricultural productivity is low and needs to be raised to reduce human hunger and poverty. However, impact of biochar research on scientists, politicians and end-users in poor tropical countries remains unknown; assessing needs and interests on biochar is essential to develop reliable knowledge transfer/translation mechanisms. The aim of this publication is to present results of a meta-analysis conducted to (1) survey global biochar research published between 2010 and 2014 to assess its relation to human development and environmental quality, and (2) deduce, based on the results of this analysis, priorities required to assess and promote the role of biochar in the development of adapted and sustainable agronomic methods. Our main findings reveal for the very first time that: (1) biochar research associated with less developed countries focused on biochar production technologies (26.5 ± 0.7%), then on biochars’ impact on chemical soil properties (18.7 ± 1.2%), and on plant productivity (17.1 ± 2.6%); (2) China dominated biochar research activities among the medium developed countries focusing on biochar production technologies (26.8 ± 0.5%) and on use of biochar as sorbent for organic and inorganic compounds (29.1 ± 0.4%); and (3) the majority of biochar research (69.0±2.9%) was associated with highly developed countries that are able to address a higher diversity of questions. Evidently, less developed countries are eager to improve soil fertility and agricultural productivity, which requires transfer and/or translation of biochar knowledge acquired in highly developed countries. Yet, improving local research capacities and encouraging synergies across scientific disciplines and countries are crucial to foster development of sustainable agronomy in less developed countries. © 2017, The Author(s)
Biochar reduces the efficiency of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) mitigating N2O emissions
Among strategies suggested to decrease agricultural soil N2O losses, the use of nitrification inhibitors such as DMPP (3,4-dimethylpyrazole phosphate) has been proposed. However, the efficiency of DMPP might be affected by soil amendments, such as biochar, which has been shown to reduce N2O emissions. This study evaluated the synergic effect of a woody biochar applied with DMPP on soil N2O emissions. A incubation study was conducted with a silt loam soil and a biochar obtained from Pinus taeda at 500 degrees C. Two biochar rates (0 and 2% (w/w)) and three different nitrogen treatments (unfertilized, fertilized and fertilized + DMPP) were assayed under two contrasting soil water content levels (40% and 80% of water filled pore space (WFPS)) over a 163 day incubation period. Results showed that DMPP reduced N2O emissions by reducing ammonia-oxidizing bacteria (AOB) populations and promoting the last step of denitrification (measured by the ratio nosZI + nosZII/nirS + nirK genes). Biochar mitigated N2O emissions only at 40% WFPS due to a reduction in AOB population. However, when DMPP was applied to the biochar amended soil, a counteracting effect was observed, since the N2O mitigation induced by DMPP was lower than in control soil, demonstrating that this biochar diminishes the efficiency of the DMPP both at low and high soil water contents.This work was funded by the Spanish Government (AGL2015-64582-C3-2-R MINECO/FEDER), by the Basque Government (IT-932-16) and by the European Union (FACCE-CSA no 276610/MIT04-DESIGN-UPVASC, FACCE-CSA no 2814ERA01A and 2814ERA02A). This work is also supported by the USDA/NIFA Interagency Climate Change Grant Proposal number 2014-02114 [Project number 6657-12130-002-08I, Accession number 1003011] under the Multi-Partner Call on Agricultural Greenhouse Gas Research of the FACCE-Joint Program Initiative. Any opinions, findings, or recommendation expressed in this publication are those of the authors and do not necessarily reflect the view of the USDA. MLC was supported by a Ramon y Cajal contract from the Spanish Ministry of Economy and Competitiveness and thanks Fundacion Seneca for financing the project 19281/PI/14
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