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CORN Nitrogen Concentration at Maturity—An Indicator of Nitrogen Status in Forage Maize
Author(s) -
Herrmann Antje,
Taube Friedhelm
Publication year - 2005
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/agronj2005.0201a
Subject(s) - silage , forage , agronomy , environmental science , mathematics , nitrogen fertilizer , zoology , biology , fertilizer
The increased awareness of potential impacts of agricultural activities on nonpoint source pollution has increased the demand for agro‐environmental policy measures and for scientifically sound indicators to control their implementation. Our objective was to investigate whether N concentration of maize ( Zea mays L.) at silage maturity, a routinely recorded quality parameter, can serve as an end‐of‐season indicator of N status. Based on 29 field trials on sandy soils in northern Germany, we derived a critical N concentration at silage maturity (CNC), i.e., the minimum N concentration necessary for maximum yield production. A quadratic‐plateau function describing dry matter (DM) yield as a function of N concentration allowed for the exclusion of all data sets not responsive to N fertilization or with luxury N uptake. For the remaining pooled data points, a mixed‐model analysis provided parameter estimates describing N concentration (Nc) as an exponential function of relative DM yield (Wrel), namely Nc = 4.4141·exp (0.0086·Wrel). Setting Wrel = 100 provided a CNC of 10.5 g N kg −1 DM. This value is in good agreement with results in the literature, which indicates the relative robustness of CNC with respect to a wide range of environmental conditions and genotypes. The CNC constant can be used to evaluate and monitor the end‐of‐season N status on a large‐area scale. Applied to an extended set of silage quality data of northern Germany, it revealed that forage maize production is characterized by significant excess of N supply in this region and leaves ample opportunity for reduction in N use without risk of any yield loss.