Top Dress Nitrogen

With the TopDress N app, you can create a variable rate task map for nitrogen side dress in potatoes. The map is based on a biomass map of your potato crop.

NDICEA

Wageningen Plant Research (WUR)

The NDICEA app provides insight into the availability of nitrogen for the crop during the growing season, the increase or decrease of organic matter in the soil in the longer term and nitrogen leaching. NDICEA makes calculations based on cultivation and fertilization data, in combination with weather data. NDICEA can calculate the effects of different scenarios. Through scenarios you can explore, among other things, the effects of different crops, green cover crops and fertilizers (type, timing and quantity). At least on 2 years of historical data (crops, yield and fertilization) is needed to provide a good starting point for the simulations. The calculation shows whether there is an increase or decrease in organic matter in the soil in the longer term, the nitrogen that will become available and the expected nitrogen uptake and the nitrogen leaching.

Use of NDICEA

The first step in using the NDICEA app is to create a scenario. Crop history can be retrieved or entered manually. For future scenarios, the information can be copied and adjusted from the existing crop history or entered manually. The NDICEA app can calculate based on this data.

The results of the NDICEA app consist of a number of graphs and tables.

  • Graph showing the available nitrogen, nitrogen uptake and nitrogen fixation over time.
  • Graph showing the mineral nitrogen of the topsoil and subsoil over time.
  • Graph of the annual cumulative nitrogen leaching
  • Graph of annual cumulative denitrification
  • Graph of precipitation and irrigation over time.
  • Graph of the pF over time.
  • Bar graph showing nitrogen mineralization from manure, organic manure, crop residues, green manures and humus.
  • Table with the mineral balance
  • Graph of organic matter over time

VRA Top-Dress N

Wageningen Plant Research (WUR)

Contact: Fedde Sijbrandij

E-mail: fedde.sijbrandij@wur.nl

Website:

Link to appstore: farmmaps.eu/en/editor/plan

Price: €20 ex BTW

With the TopDress N-app on farmmaps, you can create task maps for variable nitrogen side dress in potatoes. The app uses the general biomass and spatial variations in the biomass to generate advice and a task map.

With a nitrogen side dress system, you only give about 2/3 of the amount you would normally give when planting. The remainder is reserved for additional fertilization 4-6 weeks after the crop emerges, when the canopy has covered the soil.

The top dress N app calculates an advice from the current N-intake and an N-target number for the crop. The app estimates the N-uptake is with biomass maps from satellites, drones or nearby crop sensors. The N-target is calculated from the planting date, date of measurement and the yield forecast. 

We recommend using the CI crop index. Other indices such as WDVI and some specific crop sensor indices can also be used. 

You can then convert the absolute dose advices into a task map by setting the working width, minimum and maximum nitrogen rates and nitrogen content of the fertilizer.

The decision rules in top dress N are derived from an extensive series of field trials.

When you go through the steps in the app, you will first see the application dose rate map that shows the variation in recommended nitrogen top dressing within the field. This map is then converted into a task map that represents the place-specific product gift. This task map can be downloaded as a shape file or in ISO-XML format, and then placed in the terminal that controls the spreader.