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Corn Yield and Nitrate Loss in Subsurface Drainage Affected by Timing of Anhydrous Ammonia Application
Author(s) -
Jaynes D. B.
Publication year - 2015
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2015.01.0033
Subject(s) - anhydrous , nitrate , drainage , sowing , fertilizer , yield (engineering) , zoology , agronomy , ammonia , nitrogen , field experiment , poaceae , chemistry , environmental science , biology , ecology , materials science , organic chemistry , metallurgy
Surprisingly little research has examined the corn ( Zea mays L.) yield, N‐use efficiency (NUE), and water quality implications of N fertilizer timing. Anhydrous ammonia (AA) was applied either in the fall after harvest (F) at 196 kg N ha ‐1 , in the spring before planting (PP), or as an early sidedress (SD) at rates of 168 kg N ha ‐1 on replicated plots within a producer's field used to grow corn and soybean [ Glycine max (L.) Merr.] in a 2‐yr rotation. The field was underlain with subsurface drainage pipes (tiles) which were used to collect drainage and nitrate lost from the root zone for each plot. A fourth treatment was added when the initial fall N application was accidentally over applied by threefold on two plots (FH), allowing us to follow this one time over application over 4 yr. There were no significant differences among treatments for soybean yield. Over the two corn years, yields for the FH and SD treatments were at least 1.5 Mg ha ‐1 greater than for the F and PP treatments. The NUE and partial factor productivity for N (PFP N ) metrics in corn followed similar patterns; SD > PP > F > FH and SD > PP = F > FH, respectively. Flow‐weighted annual N concentrations in the tile drainage were significantly different and followed the pattern FH > F > SD > PP. Effects of the over application of N for the FH treatment could still be measured after 4 yr and impacted yield and nitrate losses well after the first year. Considering yield, NUE, and nitrate losses, sidedressing N was clearly superior to fall application in a corn–soybean rotation.