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Soil properties, crop production and greenhouse gas emissions from organic and inorganic fertilizer-based arable cropping systems

Chirinda, N.; Olesen, J.E.; Porter, J.R. and Schjønning, P. (2010) Soil properties, crop production and greenhouse gas emissions from organic and inorganic fertilizer-based arable cropping systems. Agriculture, Ecosystems and Environment, 139, pp. 584-594.

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Summary

Organic and conventional farming practices differ in the use of several management strategies, including use of catch crops, green manure, and fertilization, which may influence soil properties, greenhouse gas emissions and productivity of agroecosystems. An 11-yr old field experiment on a sandy loam soil in Denmark was used to compare several crop rotations with respect to a range of physical, chemical and biological characteristics related to carbon (C) and nitrogen (N) flows. Four organic rotations and an inorganic fertilizer-based system were selected to evaluate effects of fertilizer type, catch crops, of grass-clover used as green manure, and of animal manure application. Soil was sampled from winter wheat and spring barley plots in Sept 2007, April 2008, Sept 2008, i.e. before, during, and after the growth season, and analyzed for multiple attributes: total soil organic carbon (SOC), total N, microbial biomass N (MBN), potentially mineralizable N (PMN), and levels of potential ammonium oxidation (PAO) and denitrifying enzyme activity (DEA). In situ measurements of soil heterotrophic CO2 respiration and nitrous oxide emissions were conducted in plots with winter wheat. In April 2008, prior to field operations, intact soil cores were collected at two depths (0–5 cm and 5–10 cm) in plots under winter wheat. Water retention characteristics of each core were determined and used to calculate relative gas diffusivity (DP/D0). Finally, crop growth was monitored and grain yields measured at harvest maturity. The different management strategies between 1997 and 2007 led to soil carbon inputs that were on average 18−68 and 32−91% higher in the organic than inorganic fertilizer-based rotations for the sampled winter wheat and spring barley crops, respectively. Nevertheless, SOC levels in 2008 were similar across systems. The cumulative soil respiration for the period February to August 2008 ranged between 2−3 t CO2-C ha−1 and was correlated (r = 0.95) with average C inputs. In the organic cropping systems, pig slurry application and inclusion of catch crops generally increased soil respiration, PMN and PAO. At field capacity, relative gas diffusivity at 0–5 cm depth was >50% higher in the organic than the inorganic fertilizer-based system (P < 0.05). Crop yields in 2008 were generally lower in the organic rotations than in the conventional system; only spring barley in rotations with pig slurry application and incorporation of a catch crop prior to sowing obtained grain yields similar to levels achieved in the system where inorganic fertilizer was applied.


EPrint Type:Journal paper
Keywords:Catch crop; Denitrifier enzyme activity; Gas diffusivity; Inorganic fertilizer; Microbial biomass; Potential ammonium oxidation; Potentially mineralizable nitrogen.
Subjects: Soil > Soil quality > Soil biology
Soil > Nutrient turnover
Environmental aspects > Air and water emissions
Research affiliation: Denmark > DARCOF III (2005-2010) > CROPSYS - The effect of cropping systems on production and the environment
Denmark > AU - Aarhus University > AU, DJF - Faculty of Agricultural Sciences
Denmark > SOAR - Research School for Organic Agriculture and Food Systems
ISSN:0167-8809
Deposited By: Chirinda, Dr Ngonidzashe
ID Code:18511
Deposited On:29 Mar 2011 08:24
Last Modified:28 Apr 2013 07:26
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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