Ground-Based Active-Optical Sensor Algorithms for Corn (Zea mays, L.) in North Dakota.

Over fifty field sites were used to develop ground-based active-optical sensor relationships between sensor reading and corn (Zea mays, L.) and associated algorithms for directing potential in-season N application. The algorithms use the INSEY (in-season-estimate of-yield) approach developed by Oklahoma State at V6 and V12 within the algorithms. The algorithms were developed using the GreenSeeker™ and Holland Scientific Crop Circle™ sensors. The algorithms also include a minimum INSEY value possible to reduce errors from poor plant stand. Statistical analysis of the INSEY/yield relationships resulted in separate algorithms for western North Dakota fields and those in eastern North Dakota. The analysis also supported developing separate algorithms for eastern North Dakota long-term no-till fields, high clay soils with yield potential greater than 10 Mg ha-1 under conventional tillage and medium textured soils with yield potential greater than 10 Mg ha-1 under conventional tillage. An N rich strip within soil category within hybrid cultivar is the standard reading by which other field readings will be compared. Differences in yield predicted by the N rich strip corn and that predicted in other field areas will be the basis for the N application rate within the field.