EFFECT OF DELAYED NITROGEN FERTILIZATION ON MAIZE (ZEA MAYS L.) GRAIN YIELDS AND NITROGEN USE EFFICIENCY |
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| Authors: | Olga Walsh William Raun Art Klatt John Solie |
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| Institution: | 1. Montana State University, Western Triangle Ag Research Center , Conrad , Montana;2. Department of Plant and Soil Sciences , Oklahoma State University , Stillwater , Oklahoma , USA |
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| Abstract: | Maize grain yield potential can be estimated mid-season using NDVI at the V8 growth stage, thus affording delayed sidedress nitrogen (N) application. Several combinations of preplant and sidedress N at various growth stages were evaluated. Maize grain yields were maximized with 90 kg N ha-1 preplant followed by 90 kg N ha-1 sidedress at V6 or V10 (8 of 9 site-years). Delaying N application until V10 growth stage when preplant N was applied did not result in lower yields. Mid-season N supplies fertilizer at the time when crop need and N uptake are at a maximum, and thus facilitates more efficient N use. Lowest nitrogen use efficiencies (NUE) were observed with higher N rates and when all N was applied preplant. Highest NUE's were achieved with 45 kg N ha-1 preplant followed by 45 kg N ha-1 sidedress applied at V6 growth stage (8 of 9 site-years) and at V10 (6 of 9 site-years). |
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| Keywords: | nitrogen fruit crops fertilizers |
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