Trade-offs in organic nutrient management strategies across mixed vegetable farms in Southwest British Columbia
Balancing economic and environmental objectives can present trade-offs for organic farmers maximizing crop yields while maintaining core principles of ecology and health. A primary challenge for achieving this balance is nitrogen (N) and phosphorus (P) management. Meeting crop N requirements with co...
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Published in | Frontiers in sustainable food systems Vol. 6 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Frontiers Media S.A
06.10.2022
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Subjects | |
Online Access | Get full text |
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Summary: | Balancing economic and environmental objectives can present trade-offs for organic farmers maximizing crop yields while maintaining core principles of ecology and health. A primary challenge for achieving this balance is nitrogen (N) and phosphorus (P) management. Meeting crop N requirements with compost can build soil carbon (C) and soil health but often over-applies P and increases soil P and associated environmental risks. Alternatively, high-N organic fertilizers can provide N without surplus P but can be expensive and lack C inputs that composts supply. We evaluated these potential trade-offs in 2-year field trials on 20 mixed vegetable farms across three regions of Southwest British Columbia, Canada, capturing a range of climatic-edaphic conditions and organic amendments. Three nutrient management strategies were evaluated:
High Compost
: compost applied to meet crop N removal,
Low Compost
+
N
: compost applied to meet crop P removal plus an organic fertilizer to meet crop N removal, and
Typical
: varying combinations of composts and/or organic fertilizers (“typical” nutrient application on the farm). Nutrient strategies were evaluated in terms of yield, input costs, and soil properties [permanganate oxidizable C (labile C responsive to soil management), and post-season available N and P]. Soil P was 21% higher with
High Compost
than
Low Compost
+
N
. In one region characterized by inexpensive but nutrient-rich composts and soils high in P, input costs were lowest with
Typical
, but in the second year,
High Compost
outperformed
Typical
in crop yield. Principal component analysis showed a divergence in post-season
NO
3
-
between nutrient strategies in relation to compost and soil properties:
High Compost
using high-N composts increased post-season
NO
3
-
(0–30 cm), whereas relative yields in
High Compost
tended to be higher on farms with lower soil C and lower C:N composts, while yields with
Typical
were higher under opposite conditions but associated with higher post-season
NO
3
-
. Combining input types (e.g.,
Low Compost
+
N
) can meet environmental objectives in reducing surplus soil P without short-term yield or cost trade-offs compared to
High Compost
. However, maintaining soil C needs to be investigated to achieve effective ecological nutrient management in organic vegetable production with improved nutrient balances. |
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ISSN: | 2571-581X 2571-581X |
DOI: | 10.3389/fsufs.2022.706271 |