Open AccessLong‐term in‐season grain sorghum and soybean response to tillage and nitrogen management
Author(s) -
Sweeney Daniel W.,
RuizDiaz Dorivar A.
Publication year - 2020
Publication title -
agrosystems, geosciences and environment
Language(s) - English
Resource type - Journals
ISSN - 2639-6696
DOI - 10.1002/agg2.20084
Subject(s) - sorghum , agronomy , tillage , anhydrous , dry matter , conventional tillage , urea , no till farming , chemistry , soil water , biology , soil fertility , ecology , organic chemistry
Information on tillage and N management is limited regarding in‐season N uptake by grain sorghum [ Sorghum bicolor (L.) Moench] and growth of soybean [ Glycine max (L.) Merr.] on claypan soils in the eastern Great Plains. The objective of this study was to determine the 20‐yr effects of tillage (conventional, reduced, and no‐till) and N fertilization (no‐N control; knifed anhydrous NH 3 ; broadcast urea–ammonium nitrate solution, UAN; and broadcast dry urea) on grain sorghum N uptake and soybean biomass and their relationship to long‐term yields of those crops grown on a claypan soil. Nitrogen uptake at the boot stage during the first 10‐yr period was more than 20% greater with either conventional or reduced tillage compared with no‐till, and often greater with anhydrous NH 3 and urea N sources than with UAN solution or the no‐N control. During the second 10‐yr period, N uptake was generally greater with conventional and reduced tillage than with no‐till at the 9‐leaf stage, but this response did not persist to the boot stage. Anhydrous NH 3 often resulted in greater N uptake at both the 9‐leaf and boot stages compared with the other N sources. The relative yield increases with N uptake at the boot stage appeared due to increasing kernels head −1 but diminished as uptake exceeded 70−80 kg N ha −1 . Although dry matter measured at the R2 growth stage of soybean rotationally grown in even‐numbered years was about 10% greater with tilled options than with no‐till, biomass was not related to yield increases.