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Nutrient cycling in agroecosystems: nitrogen cycling in southern Sweden in the 1850s and two Tanzanian villages in the 1990s

Williams, Lars-Erik LU (1999)
Abstract (Swedish)
Popular Abstract in Swedish

För analys av agroekosystems näringsämnescirkulation presenteras här en generell modell. I centrum står födoproduktionsintensitet, mänsklig bärförmåga, uthållighet och effektivitet. Modellen kan användas på system med flera markanvändningstyper och är därför lämpad för studier i olika skalor. Jämförelser av alla slags agroekosystem, oavsett tid och rum, är möjliga. Olika näringsämnen kan analyseras med modellen. Kvävets cirkulation i Malmöhus län, 1858, och två tanzaniska byar, 1989-91, studeras som exempel. Ekologiska principer för hur människan kan öka sin födoproduktion, utifrån cirkulation av näringsämnen, diskuteras och exemplifieras. Huvudsakliga slutsatser: - Det råder en konflikt mellan... (More)
Popular Abstract in Swedish

För analys av agroekosystems näringsämnescirkulation presenteras här en generell modell. I centrum står födoproduktionsintensitet, mänsklig bärförmåga, uthållighet och effektivitet. Modellen kan användas på system med flera markanvändningstyper och är därför lämpad för studier i olika skalor. Jämförelser av alla slags agroekosystem, oavsett tid och rum, är möjliga. Olika näringsämnen kan analyseras med modellen. Kvävets cirkulation i Malmöhus län, 1858, och två tanzaniska byar, 1989-91, studeras som exempel. Ekologiska principer för hur människan kan öka sin födoproduktion, utifrån cirkulation av näringsämnen, diskuteras och exemplifieras. Huvudsakliga slutsatser: - Det råder en konflikt mellan ökad matproduktion och uthållighet. - Agroekosystem dominerade av grödoproduktion har en högre mänsklig bärförmåga och är mer effektiv, med avseende på kväveförluster per kväveenhet i matproduktionen, jämfört med system dominerade av djurproduktion. - Varken de tanzaniska eller de skånska agroekosystemen kan anses som uthålliga. - Stora kväveförluster konstateras från djurgödsel/exkrement, speciellt i de skånska systemen. - Biologisk kvävefixering på åkermark var den viktigaste införseln av kväve i de skånska agroekosystemen och har en stor potential för att förbättra kväveunderskotten på de tanzaniska åkrarna. (Less)
Abstract
This study presents a general model for analysing nutrient cycling in agroecosystems. The focus is on food production intensity, human carrying capacity, sustainability and efficiency. The model can be used on systems including different kinds of land uses, which makes it applicable for studies on different scales. Comparisons of all kinds of agroecosystems, independent of time and place, are made possible. Different kinds of nutrients can be studied with the model. Here, nitrogen cycling is used as an example. A region in Scania, southern Sweden, 1858, and two Tanzanian villages, 1989-91, are analysed. The book includes a discussion of ecological principles of how humans can increase their food production, based on nutrient cycling and... (More)
This study presents a general model for analysing nutrient cycling in agroecosystems. The focus is on food production intensity, human carrying capacity, sustainability and efficiency. The model can be used on systems including different kinds of land uses, which makes it applicable for studies on different scales. Comparisons of all kinds of agroecosystems, independent of time and place, are made possible. Different kinds of nutrients can be studied with the model. Here, nitrogen cycling is used as an example. A region in Scania, southern Sweden, 1858, and two Tanzanian villages, 1989-91, are analysed. The book includes a discussion of ecological principles of how humans can increase their food production, based on nutrient cycling and with concrete examples. Main conclusions in the thesis are: - There exists a conflict between increase of food production and sustainability. - Crop-dominated agroecosystems have higher human carrying capacities and are more efficient, concerning nitrogen losses per unit of nitrogen in the food produced, than livestock-dominated agroecosystems. - Neither the Tanzanian nor the Scanian agroecosystems can be judged as being sustainable. - There were high losses of nitrogen from livestock manure/excreta, especially in the Scanian agroecosystems. - Biological nitrogen fixation on cultivated land was the most important input in the Scanian agroecosystems and has a large potential for improving the negative nitrogen budgets of cultivated land in the Tanzanian systems. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Ebbersten, Sten
organization
publishing date
type
Thesis
publication status
published
subject
keywords
nutrient, nutrient model, nutrient cycling, nitrogen fixation, nitrogen budget, mixed system, miombo, manure, livestock, land use, historical system, food production, efficiency, crops, agroecosystem, carrying capacity, phosphorus, Scania, sustainability, Plant ecology, Växtekologi
pages
120 pages
publisher
Lund
defense location
Ecology Building, Lund University
defense date
1999-09-24 10:15
external identifiers
  • other:CODEN: SE-LUNBDS/NBBE-99/1052+120pp
ISBN
91-7105-113-9
language
English
LU publication?
yes
id
db88fc17-75ed-4048-90f5-998c2663b8be (old id 18996)
date added to LUP
2007-05-24 14:22:28
date last changed
2016-09-19 08:45:11
@phdthesis{db88fc17-75ed-4048-90f5-998c2663b8be,
  abstract     = {This study presents a general model for analysing nutrient cycling in agroecosystems. The focus is on food production intensity, human carrying capacity, sustainability and efficiency. The model can be used on systems including different kinds of land uses, which makes it applicable for studies on different scales. Comparisons of all kinds of agroecosystems, independent of time and place, are made possible. Different kinds of nutrients can be studied with the model. Here, nitrogen cycling is used as an example. A region in Scania, southern Sweden, 1858, and two Tanzanian villages, 1989-91, are analysed. The book includes a discussion of ecological principles of how humans can increase their food production, based on nutrient cycling and with concrete examples. Main conclusions in the thesis are: - There exists a conflict between increase of food production and sustainability. - Crop-dominated agroecosystems have higher human carrying capacities and are more efficient, concerning nitrogen losses per unit of nitrogen in the food produced, than livestock-dominated agroecosystems. - Neither the Tanzanian nor the Scanian agroecosystems can be judged as being sustainable. - There were high losses of nitrogen from livestock manure/excreta, especially in the Scanian agroecosystems. - Biological nitrogen fixation on cultivated land was the most important input in the Scanian agroecosystems and has a large potential for improving the negative nitrogen budgets of cultivated land in the Tanzanian systems.},
  author       = {Williams, Lars-Erik},
  isbn         = {91-7105-113-9},
  keyword      = {nutrient,nutrient model,nutrient cycling,nitrogen fixation,nitrogen budget,mixed system,miombo,manure,livestock,land use,historical system,food production,efficiency,crops,agroecosystem,carrying capacity,phosphorus,Scania,sustainability,Plant ecology,Växtekologi},
  language     = {eng},
  pages        = {120},
  publisher    = {Lund},
  school       = {Lund University},
  title        = {Nutrient cycling in agroecosystems: nitrogen cycling in southern Sweden in the 1850s and two Tanzanian villages in the 1990s},
  year         = {1999},
}