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Determination of optimum N‐supply in sugar beet by different mathematical methods
Author(s) -
Ladewig Erwin,
Märländer Bernward
Publication year - 1997
Publication title -
zeitschrift für pflanzenernährung und bodenkunde
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 0044-3263
DOI - 10.1002/jpln.19971600115
Subject(s) - mathematics , sugar beet , sugar , yield (engineering) , fertilizer , agronomy , statistics , zoology , chemistry , food science , biology , materials science , metallurgy
Various mathematical models used to predict optimum N‐supply (fertilizer‐N + N min ) for maximum root yield, sugar yield and white sugar yield were compared by fitting data from 39 field trials in Northwest Germany (1980–1992). Quadratic, modified exponential and square root models resulted in higher estimates of optimum N‐supply than did 2‐regressions and plateau type spline models with differences as high as 130 kg N/ha between models. Residual variance was lower with the latter two models. Data were grouped at 40 kg/ha intervals of N‐supply for analysis of variance and resulted in the lowest estimates for optimum N‐supply. Based on the overall average, the optimum fertilizer‐N dressings were 80 kg N/ha for root and sugar yield and 70 kg N/ha for white sugar yield while mineral soil‐N in spring was 70 kg N/ha.