Welcome to the ONFANT App

ONFANT, ON-FArm Nitrogen Trials, is a web-based interactive tool to visualize and summarize historical on-farm replicated strip trial data conducted by farmers working with the Iowa Soybean Association and guided corn nitrate survey fields across the Midwest.


Data provided by USDA-NRCS and funding received by USDA NIFA

Instructions

The plots below will be updated when zooming-in/out.
Noise for all the field coordinates was added for privacy purposes.


Description of the late-season corn stalk nitrate test

Observations of late-season corn N status were collected using the late-season corn stalk nitrate test (CSNT) and were guided by digital aerial imagery of the corn canopy. Three corn stalk samples were collected within three predominant soil types (based on their area within the fields) to characterize the field-average N status.
Stalk samples were collected (in the 20.3 to 35.6 cm (8–14 inch), above-ground portion of cornstalks) from two to five weeks after corn grain reached physiological maturity or black layer stage.

Description of the N sufficiency levels

The CSNT results are categorized into four N sufficiency levels:

  • deficient (<250 mg/kg)
  • marginal (250–700 mg/kg)
  • optimal (700–2000 mg/kg)
  • excessive (>2000 mg/kg)
Weather data collection

The weather data come from Iowa Mesonet and extracted using the R package apsimx.

The tabs below summarize the weather data (rainfall, temperature, and radiation) by year and state. You can access to the daily observations per corn field by downloading our R package onfant.

The reference rainfall, temperature and growing degree day (indicated by a black line) were averaged per state over the years the corn fields harvested. Source: Iowa Mesonet.

Monthly rainfall

Note: The reference rainfall is indicated by the black line.













Cumulative rainfall

Note: The reference rainfall is indicated by the black line.

Monthly temperature

Note: The reference temperature is indicated by the black line.

Cumulative Growing Degree Day

Note: The reference GDD is indicated by the black line.

Radiation

Note: The reference radiation is indicated by a black line.

Nitrogen rate distribution per N form

Note: NH3 = Anhydrous ammonia ; UAN = Urea Ammonium Nitrate













Nitrogen rate distribution over time across N form


Observed N rate required to reach a specific corn N status for different combination of N form and timing of application

Note: NH3 = Anhydrous ammonia ; UAN = Urea Ammonium Nitrate

Complete instructions 1/2/3 from the left sidebar panel.













Percentage of corn N status per type of N management

Complete instructions 2 and 3 from the left sidebar panel.

Percentage of corn N status per Year

Complete instruction 2 from the left sidebar panel.

Previous publications


Part of the data have been published in the following peer-reviewed papers:

  • Anderson C and Kyveryga P (2016). Combining on-farm and climate data for risk management of nitrogen decisions. Climate Risk Management. DOI: 10.1016/j.crm.2016.03.002

  • Kyveryga P et al. (2012). Normalization of uncalibrated late-season digital aerial imagery for evaluating corn nitrogen status. Precision Agriculture. DOI: 10.1007/s11119-011-9231-8

  • Kyveryga P et al. (2011). Late-season digital aerial imagery and stalk nitrate testing to estimate the percentage of areas with different nitrogen status within fields. Journal of soil and water conservation. DOI: 10.2489/jswc.66.6.373

  • Tao H et al. (2018). Factors affecting nitrogen availability and variability in cornfields. Agronomy Journal. DOI: 10.2134/agronj2017.11.0631

  • Kyveryga et al. (2010). Identification of nitrogen management categories by corn stalk nitrate sampling guided by aerial imagery. Agronomy Journal. DOI: 10.2134/agronj2009.0401

Visit our other web-application EVOS


(Photo/Iowa Soybean Association)


EVOS, Economic Viewer of On-Farm Studies, is decision-aid tool that helps farmers make economic assessments.
It was developed by the Iowa Soybean Association’s Research Center for Farming Innovation’s analytics team.

For any information, please send an email to Peter Kyveryga @ pkyveryga@iasoybeans.com or Suzanne Fey @ sfey@iasoybeans.com
To visit EVOS click here!

Visit our other web-application ISOFAST

ISOFAST, Interactive Summaries of On-Farm Strip Trials, is a web-based interactive tool to visualize and summarize historical on-farm replicated strip trial data conducted by farmers working with the Iowa Soybean Association.
To visit ISOFAST click here!




Contributors and Contact

ONFANT was created by Anabelle Laurent at Iowa State University using R Shiny.

For questions and feedback regarding ONFANT, please email alaurent@iastate.edu, femiguez@iastate.edu or pkyveryga@iasoybeans.com