Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production.

Efficient use of nitrogen (N) is essential to protect water quality in high-input organic vegetable production systems, but little is known about the long-term effects of organic management on N mass balances. We measured soil N and tabulated N inputs (organic fertilizers, compost, irrigation water,...

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Main Authors: Kathryn E White, Eric B Brennan, Michel A Cavigelli, Richard F Smith
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2022-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0267757
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author Kathryn E White
Eric B Brennan
Michel A Cavigelli
Richard F Smith
author_facet Kathryn E White
Eric B Brennan
Michel A Cavigelli
Richard F Smith
author_sort Kathryn E White
collection DOAJ
description Efficient use of nitrogen (N) is essential to protect water quality in high-input organic vegetable production systems, but little is known about the long-term effects of organic management on N mass balances. We measured soil N and tabulated N inputs (organic fertilizers, compost, irrigation water, atmospheric deposition, cover crop seed, vegetable transplant plugs and fixation by legume cover crops) and exports in harvested crops (lettuce, broccoli) over eight years to calculate soil surface and soil system N mass balances for the Salinas Organic Cropping Systems study in Salinas, CA. Our objectives were to 1) quantify the long-term effects of compost, cover crop frequency and cover crop type on soil N, cover crop and vegetable crop N uptake, and yield, and 2) tabulate N balances to assess the effects of these factors on N export in harvested crops, soil N storage and potential N loss. Results show that across all systems only 13 to 23% of N inputs were exported in harvest. Annual compost applications increased soil N stocks but had little effect on vegetable N uptake or yield, increasing the cumulative soil system N balance surplus over eight years by 999 kg ha-1, relative to the system receiving organic fertilizers alone. Annually planted winter cover crops increased N availability, crop uptake and export; however, biological N fixation by legumes negated the positive effect of increased harvest exports on the balance surplus in the legume-rye cover cropped system. Over eight years, rye cover crops improved system performance and reduced the cumulative N surplus by 384 kg ha-1 relative to the legume-rye mixture by increasing N retention and availability without increasing N inputs. Reduced reliance on external compost inputs and increased use of annually planted non-legume cover crops can improve efficient N use and cropping system yield, consequently improving environmental performance.
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spelling doaj.art-a17ca43d3def4daa888670e9d7643ac62022-12-22T00:32:42ZengPublic Library of Science (PLoS)PLoS ONE1932-62032022-01-01174e026775710.1371/journal.pone.0267757Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production.Kathryn E WhiteEric B BrennanMichel A CavigelliRichard F SmithEfficient use of nitrogen (N) is essential to protect water quality in high-input organic vegetable production systems, but little is known about the long-term effects of organic management on N mass balances. We measured soil N and tabulated N inputs (organic fertilizers, compost, irrigation water, atmospheric deposition, cover crop seed, vegetable transplant plugs and fixation by legume cover crops) and exports in harvested crops (lettuce, broccoli) over eight years to calculate soil surface and soil system N mass balances for the Salinas Organic Cropping Systems study in Salinas, CA. Our objectives were to 1) quantify the long-term effects of compost, cover crop frequency and cover crop type on soil N, cover crop and vegetable crop N uptake, and yield, and 2) tabulate N balances to assess the effects of these factors on N export in harvested crops, soil N storage and potential N loss. Results show that across all systems only 13 to 23% of N inputs were exported in harvest. Annual compost applications increased soil N stocks but had little effect on vegetable N uptake or yield, increasing the cumulative soil system N balance surplus over eight years by 999 kg ha-1, relative to the system receiving organic fertilizers alone. Annually planted winter cover crops increased N availability, crop uptake and export; however, biological N fixation by legumes negated the positive effect of increased harvest exports on the balance surplus in the legume-rye cover cropped system. Over eight years, rye cover crops improved system performance and reduced the cumulative N surplus by 384 kg ha-1 relative to the legume-rye mixture by increasing N retention and availability without increasing N inputs. Reduced reliance on external compost inputs and increased use of annually planted non-legume cover crops can improve efficient N use and cropping system yield, consequently improving environmental performance.https://doi.org/10.1371/journal.pone.0267757
spellingShingle Kathryn E White
Eric B Brennan
Michel A Cavigelli
Richard F Smith
Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production.
PLoS ONE
title Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production.
title_full Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production.
title_fullStr Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production.
title_full_unstemmed Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production.
title_short Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production.
title_sort winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production
url https://doi.org/10.1371/journal.pone.0267757
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AT michelacavigelli wintercovercropsincreasednitrogenavailabilityandefficientuseduringeightyearsofintensiveorganicvegetableproduction
AT richardfsmith wintercovercropsincreasednitrogenavailabilityandefficientuseduringeightyearsofintensiveorganicvegetableproduction