Expression of Variability in Corn as Influenced by Growth Stage Using Optical Sensor Measurements

Abstract

Improving crop management inputs with remote sensing devices is an emerging technology. This study documented the progression of the normalized difference vegetative index (NDVI) during the life cycle of corn (Zea mays L.), evaluated the spatial variability of corn growth in terms of the CV (calculated from NDVI readings), and documented the relationships between NDVI, CV (calculated from NDVI), and grain and biomass yields and plant density. Four rows, 30 m in length, from two locations during 2 yr were randomly selected for this study. An optical sensor was used to collect NDVI readings at multiple growth stages during the life cycle of corn. The NDVI increased with progression of vegetative growth stages until V10, where a plateau was encountered, followed by a decline in NDVI after the VT growth stage. Coefficient of variation data from the NDVI readings revealed two dominant peaks during the life cycle of corn, one between the V6 and V8 growth stages and the second during the late reproductive growth stages. The CV data illustrated that the greatest variation expressed by corn during the vegetative growth stages was between the V6 and V8 growth stages. The highest correlation of NDVI with corn grain yield was found at the V7 to V9 growth stages; likewise, CV and plant density were also more highly correlated from V7 to V9. The CV from NDVI readings was highly correlated with grain and biomass yields at all growth stages.

Corn Response to Climate Stress Detected with Satellite-Based NDVI Time Series

“…Compared to Cluster B both cluster A and C have relatively larger absolute values (0.2-0.4) in NDVI residuals, indicating larger growth The correlation analysis summarized in Table 5 indicates that the NDVI residual derived from Landsat images reflects crop stress in the pre-silking period that in turn impacts final yield. This result is consistent with other studies that have found that NDVI from the middle to late vegetative period is significantly correlated with biomass and final yield [46,47]. Therefore, it may be possible to predict corn grain yield in-season for this study area, by comparing pre-silking period NDVIs to long-term normal growth curves.…”

By-Plant Prediction of Corn (Zea maysL.) Grain Yield using Height and Stalk Diameter

“…Other studies (Martin et al 2007;Teal et al 2007;Raun et al, 2005) have shown that the coefficient of variation (CV) from NDVI measurements taken down the row varies widely throughout the growing season. Martin et al (2007) and Raun et al (2005) showed that CV's of NDVI measurements were highest in corn from growth stages V6-V8, and lowest from V10-VT.…”

“…By-plant variability in corn yields is well-documented (Martin et al, 2005;Teal, 2004;Freeman et al, 2007), expressing the need for management of N on a by-plant basis for corn. A study by Freeman et al (2007) revealed that NDVI, along with plant height measurements, can be used to predict by-plant corn forage yield.…”

“…A study by Freeman et al (2007) revealed that NDVI, along with plant height measurements, can be used to predict by-plant corn forage yield. This study found that an index of NDVI X plant height had a strong relationship (r² = 0.77) with N uptake from V10 to R1 growth stages (Freeman et al, 2007).…”

“…A study by Freeman et al (2007) revealed that NDVI, along with plant height measurements, can be used to predict by-plant corn forage yield. This study found that an index of NDVI X plant height had a strong relationship (r² = 0.77) with N uptake from V10 to R1 growth stages (Freeman et al, 2007). Additionally, Freeman et al (2007) found that plant height alone was a strong predictor (r² = 0.81) of dry plant biomass at growth stages V8-V10.…”