Veris Technologies OpticMapper - Application Note - Manual

Application Note: OpticMapper
Proper Mapping Techniques
1. Equipment Testing. Before mapping, perform equipment tests using electronics test
load and reference block, as recommended by Operations Manual.
2. Recognize Effects of Soil Condition. In order to generate high quality OM data
, it’s
crucial to understand that field history, soil conditions, and equipment settings can affect
estimations of OM from OpticMapper measurements. The most important consideration
is soil moisture: moist soil and organic matter are both darker in color than dry soil and
low OM, which could lead to confusing and erroneous estimations of soil organic matter.
Effective OM field mapping requires consistent moisture levels
—of course soils have
natural differences based on soil water-holding capacity--sand will have less moisture,
clay more. What are critical to prevent are management-related moisture
inconsistencies. These can be caused by:
a) A field having two or more moisture conditions, due to tillage, cropping, or irrigation
differences (Figure 1). To avoid these situations, treat each condition as a separate
field: map differing conditions on separate files, and make sure both conditions are
represented with calibration samples.
Figure1. Moisture variation between two fields mapped as one
b) Adjustment of OpticMapper during mapping —changing depth or down-pressure
which causes sensing depth to change (Figure 2). If in-field adjustments are required,