caa a22 4500 445864656 CHVBK 20180317145454.0 cr unu---uuuuu 170323e20111001xx s 000 0 eng 10.1007/s11119-010-9210-5 doi (NATIONALLICENCE)springer-10.1007/s11119-010-9210-5 Variable nitrogen rate determination from plant spectral reflectance in soft red winter wheat [Elektronische Daten] [W. Thomason, S. Phillips, P. Davis, J. Warren, M. Alley, M. Reiter] Variable rate nitrogen (N) application based on in-season remote sensing can potentially improve wheat (Triticum aestivum L.) N management and N use efficiency (NUE). The goal of this study was to evaluate the potential of improving in-season soft red winter wheat (SRWW) variable rate N recommendations based on crop canopy reflectance. Small-plot N rate response calibration studies guided development of the Virginia Wheat Algorithm (VWA) for grain yield prediction and variable rate N fertilizer rate determination for SRWW. Large plot, replicated validation studies conducted for 15 site-years included an N-rich strip installed at growth stage (GS) 25 and various treatments at GS 30; four or five fixed-rate treatments applied to evaluate site N response, a variable rate based on the VWA applied using a GreenSeeker® RT 200 system and a "standard” fixed rate based on GS 30 wheat tissue N concentration. All sites responded positively to GS 30N application. When data from one site were excluded, rates were 8 and 3kgha−1 below the economically optimal N rate (EONR) for the VWA and standard methods, respectively. Based on these data, the GreenSeeker® RT 200 system employing the VWA was equivalent to the current standard method and offers real-time rate prescriptions with less labor and less delay than the current tissue N concentration sufficiency standard. Springer Science+Business Media, LLC, 2010 Nitrogen nationallicence Variable rate nationallicence Remote sensing nationallicence Wheat ( Triticum aestivum L.) nationallicence AONR : Agronomically optimum nitrogen rate nationallicence EONR : Economically optimum nitrogen rate nationallicence GDD : Growing degree day nationallicence GS 25 : Zadoks growth stage 25 nationallicence GS 30 : Zadoks growth stage 30 nationallicence HRWW : Hard red winter wheat nationallicence INSEY : In-season estimated yield nationallicence NDVI : Normalized difference vegetation index nationallicence NIR : Near-infrared nationallicence NUE : Nitrogen use efficiency nationallicence RI : Response index nationallicence SRWW : Soft red winter wheat nationallicence VI : Vegetation index nationallicence VWA : Virginia wheat algorithm nationallicence YPI : Yield prediction index nationallicence Thomason W. Virginia Tech Department of Crop and Soil Environmental Science, Blacksburg, VA, USA aut Phillips S. International Plant Nutrition Institute, Owens Cross Roads, AL, USA aut Davis P. Virginia Cooperative Extension, New Kent, VA, USA aut Warren J. Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK, USA aut Alley M. Virginia Tech Department of Crop and Soil Environmental Science, Blacksburg, VA, USA aut Reiter M. Virginia Tech Department of Crop and Soil Environmental Science, Blacksburg, VA, USA aut Precision Agriculture Springer US; http://www.springer-ny.com 12/5(2011-10-01), 666-681 1385-2256 12:5<666 2011 12 11119 https://doi.org/10.1007/s11119-010-9210-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11119-010-9210-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Thomason W. Virginia Tech Department of Crop and Soil Environmental Science, Blacksburg, VA, USA aut NATIONALLICENCE 700 1- Phillips S. International Plant Nutrition Institute, Owens Cross Roads, AL, USA aut NATIONALLICENCE 700 1- Davis P. Virginia Cooperative Extension, New Kent, VA, USA aut NATIONALLICENCE 700 1- Warren J. Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK, USA aut NATIONALLICENCE 700 1- Alley M. Virginia Tech Department of Crop and Soil Environmental Science, Blacksburg, VA, USA aut NATIONALLICENCE 700 1- Reiter M. Virginia Tech Department of Crop and Soil Environmental Science, Blacksburg, VA, USA aut NATIONALLICENCE 773 0- Precision Agriculture Springer US; http://www.springer-ny.com 12/5(2011-10-01), 666-681 1385-2256 12:5<666 2011 12 11119 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer