Abstract
Agricultural ecosystems are one of the largest global contributors to nitrate (NO 3 − ) contamination of surface- and groundwater through fertilizer application. Improved fertilizer practices are needed to manage crop nutrient supply in corn (Zea mays L.) while minimizing impacts to clean water reserves. The goal of this study was to compare current nitrogen (N) fertilizer practices (urea at planting) with “packages” of improved management practices (a combination of right timing and product) that farmers potentially use. We conducted measurements in a continuous corn system from November 2015 to May 2017 at a large field scale (four 4 ha plots). Nitrate concentration was measured below the root zone and drainage estimated using a soil water budget approach in which evapotranspiration was measured using the eddy covariance method. The objective was to compare NO 3 − -N leaching from fields receiving urea vs. urea + combination of nitrification and urease inhibitors (NUI) fertilizer applications at planting, urea–ammonium nitrate (UAN) vs. UAN + NUI applied at sidedress, and a combination of these practices: urea + NUI at planting vs. UAN at sidedress. Drainage was only significant in the non-growing season. Neither fertilizer products applied with NUI at planting or sidedress proved to significantly reduce NO 3 − -N leaching. The combination of delaying fertilization to sidedress and applying UAN significantly reduced the soil water NO 3 − -N concentration compared with urea + NUI at planting (mean of 5.2 vs. 6.7 mg L −1 ) but only in 2015–2016. Based on these results, applying UAN at sidedress is recommended, although additional study years are needed to confirm those results.
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Claims 5
Claim · model-written summary
Drainage was significant only in the non-growing season.
- Taxon
- corn
Zea mays subsp. mayse0 - Outcome
- Drainagee1
- Qualifier
- non-growing seasone1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“continuous corn system”
e1“Drainage was only significant in the non-growing season”
Claim · model-written summary
NUI added to fertilizer at planting did not significantly reduce nitrate leaching.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- NUI at plantinge1
- Outcome
- NO 3 − -N leachinge1
- Direction
- reducee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn (Zea mays L.)”
e1“Neither fertilizer products applied with NUI at planting or sidedress proved to significantly reduce NO 3 − -N leaching”
Claim · model-written summary
NUI added to fertilizer at sidedress did not significantly reduce nitrate leaching.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- NUI at planting or sidedresse1
- Outcome
- NO 3 − -N leachinge1
- Direction
- reducee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn (Zea mays L.)”
e1“Neither fertilizer products applied with NUI at planting or sidedress proved to significantly reduce NO 3 − -N leaching”
Claim · model-written summary
Sidedress UAN reduced soil-water nitrate concentration compared with planting urea plus NUI in 2015–2016.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- delaying fertilization to sidedress and applying UANe1
- Outcome
- soil water NO 3 − -N concentratione1
- Direction
- reducede1
- Value
- 5.2 vs. 6.7 mg L −1e1
- Qualifier
- only in 2015–2016e1
- Comparator
- urea + NUI at plantinge1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn (Zea mays L.)”
e1“delaying fertilization to sidedress and applying UAN significantly reduced the soil water NO 3 − -N concentration compared with urea + NUI at planting (mean of 5.2 vs. 6.7 mg L −1 ) but only in 2015–2016”
Claim · model-written summary
The authors recommend applying UAN at sidedress, pending more study years.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- applying UAN at sidedress is recommendede1
- Qualifier
- additional study years are needede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn (Zea mays L.)”
e1“applying UAN at sidedress is recommended, although additional study years are needed to confirm those results”
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See all 93 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.