Abstract
One potential benefit of cover crops (CCs) is that N mineralization from decomposing CC residues may reduce the N fertilizer requirement of a subsequent crop, but predicting this credit remains a significant challenge. This study used a model–data fusion approach to calibrate a model of CC residue N mineralization and pre‐emptive competition for soil NO 3 − that occurs during CC growth to predict the yield response of an unfertilized corn ( Zea mays L.) crop. The model was calibrated with a data set of 199 observations from four CC experiments in central Pennsylvania. The most parsimonious model explained 82% of the variation in corn yield response. Parameters representing the C humification coefficients for decomposed residues from winterkilled (ε wk = 0.00) and winter‐hardy (ε wh = 0.40) CCs suggest that all winterkilled CCs resulted in net N mineralization, probably due to the longer period of time for decomposition of winterkilled residues. However, the yield response per unit of potentially mineralized N was greater for winter‐hardy CCs (α wh = 0.034 with tillage, α wh = 0.020 with no‐till) than for winterkilled CCs (α wk = 0.0084), probably due to the improved synchrony between corn N demand and the decomposition of winter‐hardy CC residues relative to winterkilled residues. Pre‐emptive competition for soil NO 3 − led to a reduction in the corn yield response. Because the model is based on ecological processes and can be calibrated with data sets from simple field experiments, the model–data fusion approach could be widely used to guide adaptive management of CCs and N fertilizer applications in a subsequent corn crop. Core Ideas A simple model predicts how cover crops affect N availability to the next corn crop. The model highlights the ecological controls on N supply from cover crops. Site‐specific cover crop measurements can guide adaptive N management using the model. Regional model calibration could be achieved with easily collected data.
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Claims 9
Claim · model-written summary
The parsimonious model explained 82% of corn yield response variation.
- Taxon
- corn
Zea mays subsp. mayse0 - Outcome
- variation in corn yield responsee0
- Value
- 82%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The most parsimonious model explained 82% of the variation in corn yield response”
Claim · model-written summary
Model parameters suggested all winterkilled cover crops caused net nitrogen mineralization.
Verbatim
e0“Parameters representing the C humification coefficients for decomposed residues from winterkilled (ε wk = 0.00) and winter‐hardy (ε wh = 0.40) CCs suggest that all winterkilled CCs resulted in net N mineralization”
Claim · model-written summary
The model assigned a C humification coefficient of 0.40 to winter hardy cover crop residues.
Verbatim
e0“winter‐hardy (ε wh = 0.40) CCs”
Claim · model-written summary
Yield response per potentially mineralized nitrogen was greater for winter hardy than winterkilled cover crops.
- Taxon
- CornZea mays subsp. mayst0
- Material
- winter‐hardy CCse0
- Outcome
- yield response per unit of potentially mineralized Ne0
- Direction
- greatere0
- Comparator
- winterkilled CCse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the yield response per unit of potentially mineralized N was greater for winter‐hardy CCs (α wh = 0.034 with tillage, α wh = 0.020 with no‐till) than for winterkilled CCs (α wk = 0.0084)”
t0“Corn”
Claim · model-written summary
With tillage, winter hardy cover crops had a modeled response coefficient of 0.034.
Verbatim
e0“α wh = 0.034 with tillage”
Claim · model-written summary
Without tillage, winter hardy cover crops had a modeled response coefficient of 0.020.
Verbatim
e0“α wh = 0.020 with no‐till”
Claim · model-written summary
Winterkilled cover crops had a modeled response coefficient of 0.0084.
Verbatim
e0“winterkilled CCs (α wk = 0.0084)”
Claim · model-written summary
Preemptive competition for soil nitrate reduced corn yield response.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- Pre‐emptive competition for soil NO 3 −e0
- Outcome
- corn yield responsee0
- Direction
- reductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pre‐emptive competition for soil NO 3 − led to a reduction in the corn yield response”
Claim · model-written summary
The authors propose the model data fusion approach for guiding adaptive cover crop and nitrogen fertilizer management.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- adaptive management of CCs and N fertilizer applicationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the model–data fusion approach could be widely used to guide adaptive management of CCs and N fertilizer applications in a subsequent corn crop”