caa a22 4500 445864362 CHVBK 20180317145453.0 cr unu---uuuuu 170323e20111201xx s 000 0 eng 10.1007/s11119-011-9229-2 doi (NATIONALLICENCE)springer-10.1007/s11119-011-9229-2 Evaluation of two crop canopy sensors for nitrogen variability determination in irrigated maize [Elektronische Daten] [T. Shaver, R. Khosla, D. Westfall] Advances in precision agriculture technology have led to the development of ground-based active remote sensors that can determine normalized difference vegetation index (NDVI). Studies have shown that NDVI is highly related to leaf nitrogen (N) content in maize (Zea mays L.). Remotely sensed NDVI can provide valuable information regarding in-field N variability and significant relationships between sensor NDVI and maize grain yield have been reported. While numerous studies have been conducted using active sensors, none have focused on the comparative effectiveness of these sensors in maize under semi-arid irrigated field conditions. Therefore, the objectives of this study were (1) to determine the performance of two active remote sensors by determining each sensor's NDVI relationship with maize N status and grain yield as driven by different N rates in a semi-arid irrigated environment and, (2) to determine if inclusion of ancillary soil or plant data (soil NO3 concentration, leaf N concentration, SPAD chlorophyll and plant height) would affect these relationships. Results indicated that NDVI readings from both sensors had high r 2 values with applied N rate and grain yield at the V12 and V14 maize growth stages. However, no single or multiple regression using soil or plant variables substantially increased the r 2 over using NDVI alone. Overall, both sensors performed well in the determination of N variability in irrigated maize at the V12 and V14 growth stages and either sensor could be an important tool to aid precision N management. Springer Science+Business Media, LLC, 2011 Crop canopy sensors nationallicence Remote sensing nationallicence NDVI nationallicence Shaver T. Department of Agronomy and Horticulture, University of Nebraska-Lincoln, WCREC, 69101, North Platte, NE, USA aut Khosla R. Department of Soil and Crop Sciences, Colorado State University, 80523, Fort Collins, CO, USA aut Westfall D. Department of Soil and Crop Sciences, Colorado State University, 80523, Fort Collins, CO, USA aut Precision Agriculture Springer US; http://www.springer-ny.com 12/6(2011-12-01), 892-904 1385-2256 12:6<892 2011 12 11119 https://doi.org/10.1007/s11119-011-9229-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11119-011-9229-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Shaver T. Department of Agronomy and Horticulture, University of Nebraska-Lincoln, WCREC, 69101, North Platte, NE, USA aut NATIONALLICENCE 700 1- Khosla R. Department of Soil and Crop Sciences, Colorado State University, 80523, Fort Collins, CO, USA aut NATIONALLICENCE 700 1- Westfall D. Department of Soil and Crop Sciences, Colorado State University, 80523, Fort Collins, CO, USA aut NATIONALLICENCE 773 0- Precision Agriculture Springer US; http://www.springer-ny.com 12/6(2011-12-01), 892-904 1385-2256 12:6<892 2011 12 11119 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer