Abstract
The Nutrient Management Act (NMA) established in the province of Ontario in 2002 has prompted a re-evaluation of nitrogen (N) management practices. However, N management research in Ontario is currently outdated. The experiment in this 3-year study was designed to establish the yield response of carrot ( Daucus carota ) to N fertilization on mineral and organic soils and identify the relative yield effects of preplant and residual soil N. In 2002, N was applied at 0%, 50%, 100%, 150%, and 200% of recommended N application rates in Ontario as ammonium nitrate (organic soil: 60 kg·ha -1 preplant; mineral soil: 110 kg·ha -1 split 66% preplant/33% sidedress). Experimental units were split in half in 2003 and 2004, and N was applied to one half in 2003 and both halves in 2004 to identify the effects of residual N from the previous season on yield. Crop stand, yield, and quality were assessed at harvest, and storability was assessed by placing carrots into cold storage for 6 months. Nitrogen application rate had no effect on the yield, quality, or storability of carrots grown on organic soil. On mineral soil there were no effects of applied N in the first year of the 3-year study. In the second and third year on mineral soil, yield increased in response to increasing N, up to 200% and 91% of the recommended application rate, respectively, based on the regression equations. Yield declined above 91% of the recommended application rate in the third year due to a decrease in stand at higher N application rates. There were no effects of N on carrot quality or storability on mineral soil. On mineral soil, residual N from the 2002 season had more effect on yield at harvest in 2003 than N applied in 2003. This major effect of residual soil N on yield provides an explanation for the lack of yield response to preplant N application in previous studies conducted in temperate regions. These results indicate that there is no single N recommendation that is appropriate for all years on mineral soil. Assessing the availability of N from the soil at different depths at seeding is recommended to determine the need for N application.
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Claims 9
Claim · model-written summary
Nitrogen rate did not affect carrot yield, quality or storability on organic soil.
- Taxon
- carrots
Daucus carotae0 - Treatment
- Nitrogen application ratee0
- Outcome
- yield, quality, or storabilitye0
- Direction
- no effecte0
- Setting
- organic soile0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen application rate had no effect on the yield, quality, or storability of carrots grown on organic soil.”
Claim · model-written summary
Applied nitrogen had no effect on mineral soil in the first year.
- Taxon
- CarrotDaucus carotae0t0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On mineral soil there were no effects of applied N in the first year of the 3-year study.”
t0“Carrot Yield”
Claim · model-written summary
Mineral soil carrot yield increased with N rate up to 200% of the recommendation in year two.
- Taxon
- CarrotDaucus carotae0t0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the second and third year on mineral soil, yield increased in response to increasing N, up to 200% and 91% of the recommended application rate, respectively, based on the regression equations.”
t0“Carrot Yield”
Claim · model-written summary
Mineral soil carrot yield increased with N rate up to 91% of the recommendation in year three.
- Taxon
- CarrotDaucus carotae0t0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the second and third year on mineral soil, yield increased in response to increasing N, up to 200% and 91% of the recommended application rate, respectively, based on the regression equations.”
t0“Carrot Yield”
Claim · model-written summary
Above 91% of the recommendation, third-year yield declined because stand decreased at higher N rates.
- Taxon
- CarrotDaucus carotae0t0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield declined above 91% of the recommended application rate in the third year due to a decrease in stand at higher N application rates.”
t0“Carrot Yield”
Claim · model-written summary
Nitrogen had no effect on carrot quality or storability on mineral soil.
- Taxon
- carrotDaucus carotae0
- Treatment
- Ne0
- Outcome
- carrot quality or storabilitye0
- Direction
- no effectse0
- Setting
- mineral soile0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no effects of N on carrot quality or storability on mineral soil.”
Claim · model-written summary
Residual N from 2002 affected mineral-soil yield in 2003 more than N applied in 2003.
- Taxon
- CarrotDaucus carotae0t0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On mineral soil, residual N from the 2002 season had more effect on yield at harvest in 2003 than N applied in 2003.”
t0“Carrot Yield”
Claim · model-written summary
No single mineral-soil nitrogen recommendation suits all years.
- Taxon
- CarrotDaucus carotat0
- Outcome
- no single N recommendation that is appropriate for all years on mineral soil.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there is no single N recommendation that is appropriate for all years on mineral soil.”
t0“Carrot Yield”
Claim · model-written summary
Assess soil nitrogen availability at different depths at seeding to decide N application.
- Taxon
- CarrotDaucus carotat0
- Outcome
- Assessing the availability of N from the soil at different depths at seedinge1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Assessing the availability of N from the soil at different depths at seeding is recommended to determine the need for N application.”
t0“Carrot Yield”
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