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High variability of symbiotic nitrogen fixation in farming conditions


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Riesinger, Paul and Herzon, Irina (2014) High variability of symbiotic nitrogen fixation in farming conditions. In: Rahmann, G. and Oksoy, U. (Eds.) Building Organic Bridges, Johann Heinrich von Thünen-Institut, Braunschweig, Germany, 1, Thuenen Report, no. 20, pp. 239-242.

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Symbiotic nitrogen fixation (SNF) in perennial legume-grass leys is the primary source of N to organic farming systems in northern countries. This work aimed to quantify SNF in organically managed red clover (Trifolium pratense L.)-grass leys and to relate SNF to explanatory variables. The study was carried out on 27 farms located in the coastal regions of Finland and included 117 ley crops subjected to regular organic farming practices. SNF was calculated from clover herbage dry-matter yield with an empirical model. In the accumulated first and second cuts of one- and two-year-old red clover-grass leys, SNF averaged 185.4 kg N ha-1 yr-1 (SD ± 90.0 kg N ha-1 yr-1); fixation in the aftermath added 62.1 kg N ha-1 yr-1 (SD ± 49.8 kg N ha-1 yr-1). Due to the poor persistence of red clover, SNF declined with ley age. Between- and within-field coefficients of variation of SNF in one- and two-year-old leys averaged 51.1 and 51.8%, respectively. SNF was positively related to soil fertility parameters, mainly to soil structure. It is concluded that the preceding crop value of legume-grass leys needs to be assessed individually. The spatial heterogeneity of soil properties can be reduced through site-specific amelioration and regular applications of animal manure.

EPrint Type:Conference paper, poster, etc.
Type of presentation:Paper
Agrovoc keywords:
EnglishOn-farm researchhttp://aims.fao.org/aos/agrovoc/c_33519
EnglishOrganic farming UNSPECIFIED
EnglishSpatial heterogeneity UNSPECIFIED
EnglishTrifolium pratensehttp://aims.fao.org/aos/agrovoc/c_7917
Subjects: Crop husbandry > Production systems > Pasture and forage crops
Knowledge management > Research methodology and philosophy > Systems research and participatory research
Soil > Nutrient turnover
Farming Systems > Farm nutrient management
Research affiliation: Finland > Univ. Helsinki
International Conferences > 2014: 18th IFOAM OWC Scientific Track: 4th ISOFAR Scientific Conference
Deposited By: Riesinger, D.Sc. Paul
ID Code:23522
Deposited On:26 Sep 2013 05:51
Last Modified:20 Oct 2014 08:20
Document Language:English
Refereed:Peer-reviewed and accepted
Additional Publishing Information:urn:nbn:de:gbv:253-201407-dn053621-1

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