Journal ArticleDOI
Phosphorus budget and phosphorus availability in soils under organic and conventional farming
Fritz Oehl,Astrid Oberson,H.U. Tagmann,J. M. Besson,David Dubois,Paul Mäder,H.-R. Roth,Emmanuel Frossard +7 more
TLDR
In this paper, a long-term field trial comparing a non-fertilised control (NON), two conventionally cultivated treatments (MIN, CON), and two organically-cultivated treatments (ORG, DYN).Abstract:
The aim of this work was to assess to which extent organic farming practices would affect the accumulation of total and available phosphorus (P) in a cropped soil in comparison to conventional practices. In order to achieve this, soil samples were taken from a long-term field trial comparing a non-fertilised control (NON), two conventionally cultivated treatments (MIN, CON), and two organically cultivated treatments (ORG, DYN). Soil samples were taken from each treatment at two depths (0-20 and 30-50 cm) before starting the field trial (1977) and at the end of every three crop rotations (1984, 1991 and 1998). They were then analysed for total P (Pt), total inorganic P (Pi), total organic P (Po) and isotopically exchangeable Pi. After 21 years, the average P input-output budget reached -20.9 kg P ha−1 a−1 for NON, -7.8 for DYN, -5.7 for ORG, -5.0 for MIN and +3.8 for CON. Total P, Pi as well as the amount of Pi isotopically exchangeable within 1 minute (E1) were positively correlated to the P budget. Comparison between P budget and Pt in the top- and subsoils of the fertilised treatments suggested a net transfer of P from the 0–20 to the 30–50 cm layers between 13 and 26 kg P ha−1 a−1during the first rotation and between 3 and 12 kg P ha−1 a−1during the second rotation. During the third rotation a net upward movement of P from the subsurface to the topsoil ranging between 3.7 and 10.5 kg P ha−1 a−1was estimated. In the topsoil, E1decreased from an initial value of 12 mg P kg−1 to 11 in CON, 8 in MIN, 6 in ORG, 5 in DYN and 2 in NON after 21 years. In the subsoil, E1 increased from an initial value of 2 mg P kg−1 to 4 in MIN, ORG, DYN and NON and to 6 in CON. These results show that, with the exception of NON, all treatments had still an adequate level of available P after 21 years of trial and that, in this low to moderately P sorbing soil, an equilibrated input-output budget allows to maintain P availability at a constant level. In the organic systems, yields have so far partly been attained at the expense of soil reserves or residual P from earlier fertiliser applications.read more
Citations
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Journal ArticleDOI
Comparing the yields of organic and conventional agriculture
TL;DR: A comprehensive meta-analysis is used to examine the relative yield performance of organic and conventional farming systems globally, and shows that, overall, organic yields are typically lower than conventional yields.
Journal ArticleDOI
Impact of long-term conventional and organic farming on the diversity of arbuscular mycorrhizal fungi
Fritz Oehl,Ewald Sieverding,Paul Mäder,David Dubois,Kurt Ineichen,Thomas Boller,Andres Wiemken +6 more
TL;DR: The findings show that some AMF species present in natural ecosystems are maintained under organic farming but severely depressed under conventional Farming, indicating a potentially severe loss of ecosystem function under conventional farming.
Journal ArticleDOI
Plant mechanisms to optimise access to soil phosphorus
TL;DR: Better understanding of processes that occur as a natural response of plants to P deficiency and, through better understanding, may provide opportunities for improving plant access to soil and fertiliser P in conventional and organic agricultural systems.
Journal ArticleDOI
Developments in breeding cereals for organic agriculture
Martin Wolfe,Jörg Peter Baresel,Dominique Desclaux,Isabelle Goldringer,S. P. Hoad,Géza Kovács,F. Löschenberger,Thomas Miedaner,Hanne Østergård,E. Lammerts Van Bueren +9 more
TL;DR: The need for increased sustainability of performance in cereal varieties, particularly in organic agriculture (OA), is limited by the lack of varieties adapted to organic conditions, and the needs for breeding are reviewed in the context of three major marketing types, global, regional, local, in European OA.
Journal ArticleDOI
Strategies and agronomic interventions to improve the phosphorus-use efficiency of farming systems
Richard J. Simpson,Astrid Oberson,Richard A. Culvenor,Megan H. Ryan,Erik J. Veneklaas,Hans Lambers,Jonathan P. Lynch,Peter R. Ryan,Emmanuel Delhaize,F. Andrew Smith,Sally E. Smith,Paul R. Harvey,Alan Richardson +12 more
TL;DR: In this paper, the causal edaphic, plant and microbial factors in the context of soil P management, P cycling and productivity goals of farms are explored, including better targeted P-fertiliser use, organic amendments, removing other constraints to yield, zone management, use of plants with low critical-P requirements, and modified farming systems.
References
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Journal ArticleDOI
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