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Risk and Nitrogen Application Levels

2009· article· en· W1995034750 on OpenAlexaffvenue
Predrag Rajsic, Alfons Weersink, Markus Gandorfer

Bibliographic record

VenueCanadian Journal of Agricultural Economics/Revue canadienne d agroeconomie · 2009
Typearticle
Languageen
FieldAgricultural and Biological Sciences
TopicAgricultural risk and resilience
Canadian institutionsUniversity of Guelph
Fundersnot available
KeywordsNitrogen fertilizerHumanitiesNitrogenGrain yieldEconomicsAgricultural scienceActuarial sciencePhilosophyPhysicsEnvironmental scienceHorticulture

Abstract

fetched live from OpenAlex

Stochastic weather and soil conditions are the suggested reasons why farmers tend to apply more than the recommended levels of nitrogen. This study found that uncertainty plays a role in the application decision of farmers but not in the manner typically assumed. Using a time series of field trials of corn yield to nitrogen for the same site, nitrogen was found to be a risk‐increasing input suggesting that uncertainty should decrease, rather than increase, a risk‐averse farmer's rate of nitrogen application. Similarly, viewing risk as a profit shortfall, in which fertilizer acts in the role of insurance, was also not supported with the empirical results. Instead, the key role of uncertainty is its impact on expected profits. Increasing application rates leads to lower returns in most years but the increase in profits generated under favorable growing conditions results in greater expected profits with a high application strategy. Les conditions météorologiques et pédologiques aléatoires seraient les raisons pour lesquelles les agriculteurs tendent à appliquer des doses d'azote supérieures aux doses recommandées. Selon la présente étude, l'incertitude joue un rôle dans les décisions d'application des agriculteurs, mais d'une façon différente de celle généralement supposée. À l'aide d'une série chronologique d'essais en champ mesurant le rendement du maïs en fonction de l'azote dans le même site, nous avons trouvé que l'azote était un intrant qui augmentait les risques, ce qui laisse supposer que l'incertitude devrait faire diminuer, plutôt que de faire augmenter, la dose d'application d'azote dans le cas d'un producteur qui craint les risques. De même, considérer le risque de baisse des profits où l'engrais assume le rôle d'assurance n'a pas été appuyé par les résultats empiriques. Le rôle clé de l'incertitude est son impact sur les profits prévus. L'augmentation des doses d'application entraîne une diminution des rendements la plupart des années, mais l'augmentation des profits générés dans des conditions de croissance favorables entraîne des profits prévus plus élevés grâce à une meilleure stratégie d'application.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.002
metaresearch head score (Gemma)0.013
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.998
Threshold uncertainty score0.012

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0020.013
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.001
Science and technology studies0.0000.000
Scholarly communication0.0010.001
Open science0.0000.001
Research integrity0.0010.000
Insufficient payload (model declined to judge)0.0030.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.013
GPT teacher head0.158
Teacher spread0.145 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations66
Published2009
Admission routes2
Has abstractyes

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