Corn Yield Response to Nitrogen Fertilizer Timing and Deficiency Level

Abstract

Nitrogen fertilizer is typically applied to corn (Zea mays L.) shortly before planting, but there are several reasons why later N applications may be of interest: to spread work away from the busy planting season, to avoid the frequent wet field conditions in spring, to reduce or remedy in‐season N loss in wet years, or to allow use of in‐season diagnostic tools. One of the obstacles to the use of later N applications is the fear that irreversible yield loss will occur due to N stress. Our objective was to evaluate the yield impact of delaying N applications until the late vegetative growth stages and as far as silking. We conducted a total of 28 experiments with timing of a single N application as the experimental treatment. We found little or no evidence of irreversible yield loss when N applications were delayed as late as stage V11, even when N stress was highly visible. There was weak evidence of minor yield loss (about 3%) when N applications were delayed until stage V12 to V16. Only 3 of the 28 experiments had N applications later than V16—all were at silking and relative yields were 0.71, 0.89, and 0.95. Though full yield was not achieved when N applications were delayed until silking, yield was still highly responsive to N application at this stage—yield response exceeded 2.2 Mg ha−1 in all three experiments.

Maize response to nitrogen fertilization timing in two tillage systems in a soil with high organic matter content

“…Finally, the reduced period of early crop growth, usually observed with delayed N application when maize is sown after black oat, has less effect on grain yield when corn is planted in the beginning of spring (Russele et al, 1983;Scharf et al, 2002). At this time, air temperatures are low and maize grows slowly, which gives the crop more time to recover from early cycle stresses without compromising the formation of yield component (Sangoi, 1993).…”

“…In addition, it may decrease the disparity of yield losses due to N stress if rainy springs delay the planned side-dress application time (Scharf et al, 2002). Conversely, the anticipation of N fertilization may favor N loss by leaching due to the low N uptake capacity of maize in early growth stages (Blackmer et al, 1992;Scherer, 2001).…”

A visible band index for remote sensing leaf chlorophyll content at the canopy scale

“…Correlations found for the 6 July AVIRIS image and 16 July Landsat 5 TM image were mostly caused by the data from the plots with 0 kg N ha −1 . Scharf et al (2002b) found that nitrogen fertilizer applications could be delayed during maize vegetative growth (growth stages V1-V15), but losses in yield occurred when maize reaches reproductive growth stages without sufficient nitrogen. The AVIRIS data acquired on 6 July indicated that it is possible to use remote sensing to detect severe nitrogen deficiency (0 kg N ha −1 plots).…”

Variability in Corn Yield Response to Nitrogen Fertilizer in Eastern Canada

“…Nitrogen fertilizer rates needed for corn vary largely among fields and also within fields (Scharf et al, 2002), due to variations in crop uptake demand, soil N supply, and losses from the soil. Identifying the EONR is very important in high N-demanding crops such as corn, to maximize profitability and to reduce N losses to the environment (Wang et al, 2003;Kyveryga et al, 2009).…”