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| Munkholm, Lars J.; Schjønning, Per; Debosz, Kasia; Jensen, Henry E.; Christensen, Bent T.. |
| Current concern for soil quality has stimulated research on soil biological and chemical properties. In contrast, the mechanical behaviour of soil is somewhat neglected. We have examined the effects on soil mechanical properties of more than 100years of contrasting fertilization employing three treatments from the Askov long-term experiment: UNF (unfertilized), NPK (mineral fertilized) and AM (animal manured). We have measured tensile strength of aggregates when air-dry and when adjusted to 10, 30 and 100kPa pressure potential. Four aggregate size classes were investigated (1-2, 2-4, 4-8 and 8-16mm diameter). Soil fragmentation was characterized in the field using a drop-shatter test. Bulk soil strength was determined in the field using a shear vane and a... |
| Tipo: Journal paper |
Palavras-chave: Soil. |
| Ano: 2002 |
URL: http://orgprints.org/32/1/j.1365-2389.2002.00424.x.pdf |
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| Christensen, Bent T.. |
| Jordens frugtbarhed afhænger af et komplekst samspil mellem naturgivne og menneskeskabte forhold. En karakterisering af jordens frugtbarhed kræver bestemmelse af flere nøgleparametres udvikling over tid. Begrebet jordens frugtbarhed kan meningsfyldt defineres som jordens evne til vedvarende at understøtte en landbrugsmæssig planteproduktion, der er forsvarlig med hensyn til omfang, kvalitet, rentabilitet og påvirkning af det omgivende miljø. Jordens frugtbarhed vil således være påvirket af driftsform og planteproduktionens teknologiske og økonomiske rammer. |
| Tipo: Journal paper |
Palavras-chave: Soil quality. |
| Ano: 2000 |
URL: http://orgprints.org/339/1/Jordens_frugtbarhed.pdf |
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| Guggenberger, Georg; Christensen, Bent T.; Rubæk, Gitte H.. |
| Labile soil organic phosphorus (Po) plays a crucial role in plant P nutrition and in environmental eutrophication. This paper discusses recent studies on the nature of labile soil Po and its response to different fertilization practices. Soil material was obtained from the Askov long-term experiment on animal manure and mineral fertilizers. Our analytical approach combined a macroporous anion exchange resin to isolate labile Po and 31P NMR spectroscopy to assess the chemical composition and origin of NaOH-extractable Po. The analyses were carried out on fine earth (<2 mm) and particle-size fractions. The results suggest that the resin extraction isolates an active pool of soil Po that consists primarily of microbially-derived compounds. The size of the... |
| Tipo: Journal paper |
Palavras-chave: Soil quality. |
| Ano: 2000 |
URL: http://orgprints.org/337/1/Organic_phosphorus_pools.pdf |
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