About the OpticMapper and Soil OM
The OpticMapper is an optical sensor that measures soil reflectance. Soils that are higher in organic matter (OM) absorb more light, but can also appear darker when moist. The OpticMapper senses the subsurface where the moisture effect is minimized, and where soil color is primarily related to soil organic matter variations.
Why It Matters
If you want to vary inputs based on productive capacity, a precise map of organic matter is crucial. Soil OM is an indicator of past productivity, and a driver of current productivity. Because organic matter forms slowly over time, soils that are higher in organic matter possess improved soil texture, drainage, and other factors that consistently generate additional plant growth – resulting in higher soil OM. That increased OM level also leads to even higher productive capacity – due to better water and nutrient-holding ability, nitrogen mineralization, and soil structure. On fields where organic matter is added through manure or other amendments, an OM map reveals where levels are low, and could benefit from additional OM.
The Equipment
The OpticMapper has a dual-wavelength optical sensor mounted within a specially-configured planter row unit – mapping soil underneath crop residue and dry surface soil. Soil measurements are acquired through a sapphire window on the bottom of a furrow ‘shoe’. Readings are collected every second and matched to their GPS location. The row unit design with side depth-gauging wheels assures consistent depth – adjustable from 25-75mm.
Applications
Most precision agricultural applications can be improved with an accurate OM map layer – variable rate population, nitrogen management, sampling zones, soil amendments, herbicides, cultivar selection, and more.
