Using Productivity Maps
In this tutorial, you can download a sample dataset with Productivity Maps layers, and review sample applications, including:
- Variability analysis → improves the knowledge about within-field variability, supporting management decisions, creating management zones, selecting areas for research, etc.
- Support for directed sampling → Using the productivity map for directed sampling, the agronomist can find limiting factors.
- Creating Prescription maps → Productivity maps can be used as base maps for prescription maps, to reduce inputs in areas with low potential, and optimize areas with high yields
- Can complement / replace more data intensive approaches for applying variable rate technologies: grid sampling / yield mapping.
Prior to carrying out these exercises, it's recommended to review these articles:
- 1 Download sample data
- 2 Exercise 01 - Review information related with the Productivity map
- 3 Exercise 02 – Directed sampling based on the productivity maps
- 4 Exercise 03 – Create a Prescription map based on producitivity zones
- 5 Exercise 04 – Share the Prescription map with the applicator or other team members
Download sample data
For these exercises we are going to use a sample dataset: 'Sample Farm_Remote Sensing'.
For this purpose, you can follow the steps detailed in Download sample data,
- Create new Project with the name: 'Sample Farm_Remote Sensing'
- As the initial dataset, select 'Sample Farm_Remote Sensing', which can be found under the 'Tutorials_en' folder:
The first step is to analyze all the information related with the sample productivity map.
Review crop history and Vegetation index (NDVI) from previous years
In the references panel, under the Base Map group, you will find Landsat imagery layers, and the processed NDVI layers for each Landsat image.
Double-click on one the NDVI layers that you'll find in the reference panel, to turn it on and zoom to its extents: 'ndvi_LANDSAT_20100701_024_032'
In the name: ndvi_LANDSAT_20100701_024_032:
- ndvi is Normalized Differential Vegetation Index
- LANDSAT, is the satellite system used, in this case images from the Landsat Program
- 20100701 is the date that the image was taken, in format yyyymmdd, where yyyy is the year, mm is the month, and dd is the day.
- 24_032 is the path and row, which indicates what landsat image area was used. For more information on path/row visit the Landsat Program world reference system
The NDVI for landsat imagery for 20100701 (Jul. 1st , 2010) is shown.
Also, crop history can help us to understand the resulting NDVI maps by reviewing the correspondence between NDVI and crop history.//put link
- Please download the crop history for the sample farms from this link , and open the table.
The layer ndvi_LANDSAT_20100701_024_032 corresponds to July 7th, 2010; we can see that fields 1,3,4, had Corn planted, and fields 2,5 had Soybeans planted.
- Turn off layer 'ndvi_LANDSAT_20100701_024_032' (see how to turn a layer on/off ) ,
- Turn on layer 'ndvi_LANDSAT_20090628_024_032'; this layer corresponds to the crops in June 28th, 2009 , we can see that fields 2,3,4, 5 had Corn planted, and field 1 had Soybeans planted.
Review Productivity maps
Now let's review how each Productivity map was created.
- Click on the group Productivity Maps, to expand it and see the list of productivity maps for each field.
- Double click on layer 'ProductivityMap_Field_1' to make it active, visible and zoom to its extents.
- Go to the Query tool, and select the option 'Quey data by layer'.
The attribute table for all the objects in the layer will open.
- move to the column “Descrip” to see which NDVI layers where used to obtain the productivity map in Field 1. You may use your mouse to widen the table display, and the width of column 'Descrip'
- The 'Descrip' column shows that NDVI from dates Jul. 1st, 2010, and Jul 27, 2008 were used to create the productivity map.
Exercise 02 – Directed sampling based on the productivity maps
Create a Soil Sampling layer
- Select the new layer tool to create a new soil sampling layer //add tool figure
- Choose the vector layer option
- Structure: ….. (this structure contains fields where you can enter soil attributes values, such as Organic Matter – OM, SoilPH, P or K
- Group: ….
- Name: ….
- Use the add new object tool //put tool figure to create new points.
- Select locations where productivity is very low (light green areas), so we can evaluate these locations in the field
PM7 // add sample nrs. PM8
Download soil sampling locations to the GPS device
//from the tutorial of download sampling points PM9→ put screens with points
// enter soil values
Enter soil attributes values
If you'd like to enter → select all select sample nr. Enter attribute value.....
Exercise 03 – Create a Prescription map based on producitivity zones
we are assuming that based on soil lab results, Soil PH is the limiting factor
- select prescription tool
- select reference layer
- enter input rates ….
- assign input rates to management zones areas
- finish and create map
We are going to export to shapefile format, so the applicator can …
- select export to shape //put tool icon
- select layer to export – note that you can choose which fields
- save to local folder
- use zip
export to .lay.....