2026-09-21T21:00:49Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/97447 2023-07-11 col_2142_5131 col_2142_14798 com_2142_5130 com_2142_686 com_2142_397

Below, Frederick E. HUber, Steve Mulvaney, Richard Mann, Shelby Melissa 2017-08-10T19:15:58Z 2017-08-10T19:15:58Z 2017-04-27 2017-05 For optimal productivity, soybean [Glycine max (L.) Merr.] may require fertilizer nitrogen (N) to supplement biological N fixation. The objective of this study was to identify the best fertilizer source and the best plant growth stage for N applications to increase soybean yield using N fertilization. Trials were established at three locations in Illinois during three consecutive years for a total of nine site-years. In 2014, five different N sources were supplied and in 2015 and 2016, seven different N sources were supplied at one of four different soybean growth stages (preplant, V3, R1, and R3) at an application rate of 112 kg N ha-1 (100 lb N ac-1). The seven different N sources evaluated were: ammonium nitrate (AN, 34-0-0), ammonium sulfate (21-0-0-24S), ESN (environmentally-smart nitrogen, 44-0-0), urea + Limus (urea treated with the urease inhibitor Limus, 46-0-0), liquid urea-ammonium nitrate (UAN, 28-0-0), urea (46-0-0), and a mixture of ammonium nitrate, potassium nitrate, and ammonium sulfate (30-0-7-2S), along with an unfertilized control. When averaged across all locations, significant increases in yield occurred when N was supplied during the early growth stages (preplant and V3) in 2014 and 2016. While in 2015, significant increases in yield were more apparent from N applications during the reproductive growth stages (R1 and R3). Fertilizing with AN or ESN at preplant produced the most consistent yield increases over the nine site-years. However, when examining the individual locations, variation in N source and the application time that gave the greatest yield increase was evident, suggesting that yield increases are dependent upon a given location, N source, and/or application time. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-08-10 without embargo terms The student, Shelby Mann, accepted the attached license on 2017-04-23 at 18:37. The student, Shelby Mann, submitted this Thesis for approval on 2017-04-23 at 18:44. This Thesis was approved for publication on 2017-04-27 at 16:30. DSpace SAF Submission Ingestion Package generated from Vireo submission #11000 on 2017-08-10 at 13:45:34 Made available in DSpace on 2017-08-10T19:15:58Z (GMT). No. of bitstreams: 2 MANN-THESIS-2017.pdf: 551001 bytes, checksum: 477690bf160758d8de260ee29d9d4d34 (MD5) LICENSE.txt: 4208 bytes, checksum: 6dc7b050e3a50739177beefe6fc967f7 (MD5) Previous issue date: 2017-04-27 application/pdf http://hdl.handle.net/2142/97447 en Copyright 2017 Shelby Mann Soybean Nitrogen The use of fertilizer nitrogen applications to increase productivity of soybean text text Crop Sciences Crop Sciences University of Illinois at Urbana-Champaign Thesis M.S.