Comparison of two ground-based active-optical sensors for in-season estimation of corn (Zea mays, L.) yield

Thirty field experiments were conducted in North Dakota during 2011 and 2012 to compare two ground-based active-optical sensors for their relationship between sensor readings and INSEY (in-season estimate of yield). The experimental design at each site was a randomized complete block with four replications and six nitrogen (N) rate treatments: control, 45, 90, 134, 179, and 224kg ha(-1) applied pre-plant as ammonium nitrate within five days of planting. The two sensors, GreenSeeker (R) (Trimble, Sunnydale, CA, USA) (GS) and Crop Circle ACS 470 (R) sensor (Holland Scientific, Lincoln, NE, USA) (CC) were used to scan over the top of the corn at V6 and V12 growth stages. The GS INSEY and the CC INSEY were similarly related to corn yield at V6. The CC using the red-edge lens option improved the INSEY relationship to corn yield compared to the GS or the CC using the red lens option at V12.