Assessing soil nitrogen availability in contrasting cropping systems at the end of transition to organic production

K. Liu¹, A. M. Hammermeister¹, P. R. Warman², C. F. Drury³ and R. C. Martin^1*

Abstract
Quantifying soil nitrogen (N) availability at the end of a transition period for converting conventional fields to organic fields could enhance N management during the subsequent organic crop production phase.

Soil total N (N_tot), KCl extractable N (KCl-N) and potentially mineralizable N (N_o) were determined at the end of a 3-yr transition period. A complementary greenhouse ryegrass N bioassay was conducted using soils collected from the treated field plots. The field experiment consisted of six cropping systems comprising two N inputs (legume-based vs. manure-based) and three forage cropping treatments (0, 1 or 2 yr of forage in 4-yr rotations). The N input treatments consisted of alfalfa meal in the legume-based cropping system (LBCS) and composted beef manure in the manure-based cropping system (MBCS).

Orthogonal contrasts suggested no differences in N_tot or KCl-N either between LBCS and MBCS or between no-forage and forage cropping systems. However, in the greenhouse study, high cumulative N inputs in the MBCS resulted in significantly higher ryegrass N uptake and potentially mineralizable soil N than in the LBCS. Ryegrass N uptake ranged from 101 to 139 kg ha⁻¹, which should be an adequate N supply for the succeeding potato crop. In the greenhouse, a ryegrass N bioassay effectively identified the differences in soil N availability. Ryegrass N uptake was linearly related to cumulative soil amendment N inputs but had no apparent relationship with N_o.

A systems approach provided a good assessment of N availability at the end of the transition period to organic production.

Source
Canadian Journal of Soil Science (2011) 91: 493-501
DOI: 10.4141/cjss2010-039

Author Locations and Affiliations
(1) Organic Agriculture Centre of Canada, Nova Scotia Agricultural College, Box 550, Truro, Nova Scotia, Canada B2N 5E3
(2) Department of Plant and Animal Sciences, Nova Scotia Agricultural College, Box 550, Truro, Nova Scotia, Canada B2N 5E3
(3) Greenhouse and Processing Crops Research Centre, Agriculture and Agri-Food Canada, Harrow, Ontario, Canada N0R 1G0
* Corresponding author, E-mail rmartin@nsac.ca

en français

Posted August 2011


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Research Extension Courses Consumers -------------------------- Virtual Tours Student & Job Opportunities News Articles Standards -------------------------- Market Information Events Issues Animal Welfare Strategic Plans -------------------------- Links Award-winners Site Map	Assessing soil nitrogen availability in contrasting cropping systems at the end of transition to organic production K. Liu¹, A. M. Hammermeister¹, P. R. Warman², C. F. Drury³ and R. C. Martin^1* *Abstract* Quantifying soil nitrogen (N) availability at the end of a transition period for converting conventional fields to organic fields could enhance N management during the subsequent organic crop production phase. Soil total N (N_tot), KCl extractable N (KCl-N) and potentially mineralizable N (N_o) were determined at the end of a 3-yr transition period. A complementary greenhouse ryegrass N bioassay was conducted using soils collected from the treated field plots. The field experiment consisted of six cropping systems comprising two N inputs (legume-based vs. manure-based) and three forage cropping treatments (0, 1 or 2 yr of forage in 4-yr rotations). The N input treatments consisted of alfalfa meal in the legume-based cropping system (LBCS) and composted beef manure in the manure-based cropping system (MBCS). Orthogonal contrasts suggested no differences in N_tot or KCl-N either between LBCS and MBCS or between no-forage and forage cropping systems. However, in the greenhouse study, high cumulative N inputs in the MBCS resulted in significantly higher ryegrass N uptake and potentially mineralizable soil N than in the LBCS. Ryegrass N uptake ranged from 101 to 139 kg ha⁻¹, which should be an adequate N supply for the succeeding potato crop. In the greenhouse, a ryegrass N bioassay effectively identified the differences in soil N availability. Ryegrass N uptake was linearly related to cumulative soil amendment N inputs but had no apparent relationship with N_o. A systems approach provided a good assessment of N availability at the end of the transition period to organic production. *Source* Canadian Journal of Soil Science (2011) 91: 493-501 DOI: 10.4141/cjss2010-039 *Author Locations and Affiliations* (1) Organic Agriculture Centre of Canada, Nova Scotia Agricultural College, Box 550, Truro, Nova Scotia, Canada B2N 5E3 (2) Department of Plant and Animal Sciences, Nova Scotia Agricultural College, Box 550, Truro, Nova Scotia, Canada B2N 5E3 (3) Greenhouse and Processing Crops Research Centre, Agriculture and Agri-Food Canada, Harrow, Ontario, Canada N0R 1G0 * Corresponding author, E-mail rmartin@nsac.ca en français Posted August 2011
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Assessing soil nitrogen availability in contrasting cropping systems at the end of transition to organic production

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