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Oborn I Modin-Edman AK Bengtsson H Gustafson GM Salomon E Nilsson SI Holmqvist J Jonsson S Sverdrup H 《Ambio》2005,34(4-5):301-310
A systems analysis approach was used to assess farmscale nutrient and trace element sustainability by combining full-scale field experiments with specific studies of nutrient release from mineral weathering and trace-element cycling. At the Ojebyn dairy farm in northern Sweden, a farm-scale case study including phosphorus (P), potassium (K), and zinc (Zn) was run to compare organic and conventional agricultural management practices. By combining different element-balance approaches (at farmgate, barn, and field scales) and further adapting these to the FARMFLOW model, we were able to combine mass flows and pools within the subsystems and establish links between subsystems in order to make farm-scale predictions. It was found that internal element flows on the farm are large and that there are farm internal sources (Zn) and loss terms (K). The approaches developed and tested at the Ojebyn farm are promising and considered generally adaptable to any farm. 相似文献
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Marit?StrandenEmail author Tonette?R?stelien Ilme?Liblikas Tor?J.?Almaas Anna-Karin?Borg-Karlson Hanna?Mustaparta 《Chemoecology》2003,13(3):143-154
Summary. Some plant volatiles are produced in response to
herbivory of several insect species, including heliothine
larvae. In the present study of female heliothine moths, four
co-located receptor neurone types were identified, of which
three types responded strongest to the inducible compounds
E--ocimene, E,E--farnesene and E,E-TMTT, respectively.
The fourth type responded strongest to geraniol,
which is a common floral volatile. The narrow tuning of
each receptor neurone type was demonstrated by responses
to a few structurally-related monoterpenes, sesquiterpenes,
homo-terpenes and monoterpene alcohols, respectively, out
of hundreds of plant constituents tested. The four neurone
types showed the same relation of spike amplitudes and
ranking of effective compounds in the three heliothine
species; the polyphagous Heliothis virescens and
Helicoverpa armigera and the oligophagous Helicoverpa
assulta. The results indicate the presence of functionally
similar types of plant odour-receptor neurones in the three
related species, and suggest conservation or reappearance of
functionally similar olfactory receptors in related species,
independent of the evolution of polyphagy and oligophagy. 相似文献
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