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Corn Response to Nitrogen Management under Fully‐Irrigated vs. Water‐Stressed Conditions
Author(s) -
Maharjan Bijesh,
Rosen Carl J.,
Lamb John A.,
Venterea Rodney T.
Publication year - 2016
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2016.01.0006
Subject(s) - loam , agronomy , soil water , nitrogen , urea , environmental science , irrigation , nitrification , nitrate , zea mays , grain yield , chemistry , zoology , biology , soil science , organic chemistry
Characterizing corn ( Zea mays L.) grain yield (GY) response to N is critical for maximizing profits, increasing N use efficiency and minimizing environmental impacts. Although a large database of GY response to N exists for highly productive soils, few data exist for less productive soils. While changes in precipitation are expected in the future, few studies have compared GY response to varying N management practices under conditions of varying water availability. We measured GY and basal stalk nitrate nitrogen (BSN) at harvest using split‐applied urea at eight N rates under fully‐irrigated (FI) and water‐stressed (WS) conditions in a loamy sand over 2 yr (2009 and 2010). We also measured GY and BSN using single, pre‐plant applications of urea, polymer‐coated urea (PCU) and urea amended with urease and nitrification inhibitors (IU) at one or two N rates. The results showed that economic optimum nitrogen rate (EONR) and agronomic optimum nitrogen rate (AONR) did not vary by water management, in spite of significant increases in GY (up to 48%) under FI compared to WS. Modification of N fertilizer timing or N source was effective for increasing GY (by 18–41%) with FI, but did not affect GY under WS conditions. Averaged across years, BSN was greater with WS compared to FI at most N rates; however, BSN corresponding to AONR was within the optimal range for both water regimes. These findings may have important implications in areas where changes in irrigation practices or water availability are expected under future climate conditions. Better understanding of water stress effects on corn response to N is needed. We measured yield response to N management with full irrigation and under water‐stress. Optimum N rate did not vary by water management despite significant yield differences. Optimizing fertilizer timing or source increased yield but only with full irrigation. Basal stalk nitrate was higher with water‐stress than with full irrigation.