Comparing nitrogen timing and sidedressing placement strategies on corn growth and yield in Michigan

Abstract

Spring and summer weather volatility plus poor N use efficiency emphasize the importance of improving corn (Zea mays L.) N management strategies. Synchronizing N application with crop uptake and flexibility for in‐season sidedressing placement options may reduce N losses. Field studies in Michigan evaluated four N timing strategies: broadcast pre‐emergence (PRE), sidedressing at V4 to V6 (0:100), a 50:50 split between preplanting incorporation and sidedressing at V4 to V6 (50:50), and 40 lb N acre–1 applied 2 inches below and laterally from the seed at planting followed by sidedressing at V4 to V6 (2 × 2). Within the 0:100, 50:50, and 2 × 2 strategies, the two sidedressing placement methods included coulter injection (CInj) and Y‐drop surface application (YD). The PRE N strategy and YD placement were applied with and without a urease inhibitor (UI). During dry soil conditions following application, N timing, sidedressing placement, and their combinations did not affect grain yield. The agronomic efficiency (AE) of applied N increased by 11.2 to 13.5% with 2 × 2 and 0:100 compared with 50:50 and PRE and increased by 7.8% with CInj over YD, suggesting greater application efficiency with delayed N application and CInj placement. Grain yield, net economic return, and AE were not affected by UI. Midseason N applications allow greater flexibility and adjustments to rate and placement but uptake may be restricted with limited soil moisture. The benefits of YD surface placement may be better realized with adequate surface moisture or as late‐season rescue N applications.

Isotopic evaluation of in‐season Y Drop applications for corn production

“…Further examination of Table 5 reveals that an equal split of fertilizer N applied just before planting and as a V9 sidedress had no yield benefit over a single preplant N application. Similar results have been reported previously (Eckert, 1987(Eckert, , 1990Gordon et al, 1993;Maddux & Barnes, 1985;Purucker & Steinke, 2020), although splitting can be advantageous under some conditions, particularly when UAN is broadcast without incorporation (Eckert, 1990;Gordon et al, 1993) or is applied to calcareous soils (Pearson, 1994).…”

“…One approach is to improve the synchrony between fertilizer timing and crop N demand, which becomes feasible by splitting the total amount of fertilizer N among multiple applications during the growing season. When implemented for corn between V4 and V10, this strategy has sometimes been effective for increasing grain yields (Bushong et al., 2016; Davies et al., 2020; Eckert, 1990; Gehl et al., 2005; Gordon et al., 1993; Pearson, 1994) or fertilizer 15 N uptake efficiency (F 15 NUE) (Gerwing et al., 1979; Lange et al., 2008), but more often there has been no significant difference in yield (Bushong et al., 2016; Davies et al., 2020; Eckert, 1987, 1990; Gehl et al., 2005; Gordon et al., 1993; Menelik et al., 1994; Purucker & Steinke, 2020; Randall et al., 1997, 2003; Tran et al., 1997) or F 15 NUE (Lange et al., 2008; Tran et al., 1997). Beyond V10, these applications are unlikely to prove beneficial (e.g., Mueller et al., 2017; Nafziger & Rapp, 2021; Rutan & Steinke, 2018) and may even decrease yield (Bair et al., 1990).…”

“…Another approach for increasing FNUE is to maximize soil retention of fertilizer N by incorporation. Corn grain yields have sometimes been higher with subsurface than surface placement of urea‐ammonium nitrate (UAN) solution (Huber et al., 1982; Mengel et al., 1982; Stecker et al., 1993; Touchton & Hargrove, 1982); however, the predominant finding has been no significant difference between the two application techniques (Bundy et al., 1992; Eckert, 1987; Fox et al., 1986; Huber et al., 1982; Mengel et al., 1982; Murphy & Ferguson, 1997; Purucker & Steinke, 2020; Stecker et al., 1993; Timmons & Baker, 1992; Touchton & Hargrove, 1982). The latter finding is consistent with 15 N tracer studies showing no significant benefit of incorporation for increasing F 15 NUE (Karlen et al., 1996; Lara Cabezas et al., 2000), although the results are difficult to interpret because the UAN used was not dual‐labeled with both CO( 15 NH 2 ) 2 and 15 NH 4 15 NO 3 .…”

Corn Grain Yield Prediction and Mapping from Unmanned Aerial System (UAS) Multispectral Imagery

“…Sidedressing at V4 and V6 resulted in yields similar to those obtained with the N-rich treatment (Figure 4), even though only 60% of the N was applied for sidedressing. These findings are similar to those of [32], which reported that the yield was not impacted by sidedressing at V4 to V6 compared to an N-rich treatment, independent of the N application method. Sidedressing at V8 and V10 still increased the yield beyond the zero-N control but the yield averaged 95 and 91% of the yield obtained by N-rich treatment, respectively.…”

Estimating Nitrogen Use Efficiency, Profitability, and Greenhouse Gas Emission Using Different Methods of Fertilization

“…The projected efficiency of the DP group was 3% less than that of the TD group, representing a significant gap between the two groups. Purucker and Steinke (2020) stated that deep placement fertilization reduces nitrogen losses and increases the efficiency level. The study further shows a gap of 12% and 9% from the mean to maximum efficiency of TD and DP groups, which implies that TD and DP group can increase their efficiency up to 12 and 9%, respectively, with a given amount of inputs.…”