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Critical Compositional Nutrient Indexes for Sweet Corn at Early Growth Stage
Author(s) -
Khiari Lotfi,
Parent Léon-Étienne,
Tremblay Nicolas
Publication year - 2001
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/agronj2001.934809x
Subject(s) - nutrient , mathematics , fertilizer , zea mays , crop , agronomy , yield (engineering) , growing season , zoology , biology , ecology , physics , thermodynamics
It would be instrumental to define nutrient norms from small‐size crop databases at the V4–V6 corn (Zea mays L.) growth stage for in‐season N fertilizer recommendations. Our objective was to derive Compositional Nutrient Diagnosis (CND) and Diagnosis and Recommendation Integrated System (DRIS) nutrient index ranges from a sweet corn database and to relate nutrient concentration and indexes to ear yield. A sweet corn database of 240 observations on commercial yields and N, P, K, Ca, and Mg concentrations in 30‐cm high corn seedlings were divided at random between survey ( n = 200) and validation ( n = 40) subpopulations. The proportion of low‐yield specimens in the survey population was computed at inflection point of a cubic cumulative variance ratio function and was associated with a chi‐square value (CND r 2 ) of 3.9 that was confirmed in the validation subpopulation. Critical CND nutrient indexes were found to be symmetrical about zero as follows: −0.70 to +0.70 for N, −0.45 to +0.45 for P, −1.14 to +1.14 for K, −0.63 to +0.63 for Ca and Mg, and −1.05 to +1.05 for the residual filling value. Summing squared critical nutrient indexes also gave a CND r 2 of 3.9, the minimum CND imbalance index for high‐yield targets (>6.7 Mg ha −1 ). Nutrient concentration values were little to closely related to CND indexes ( R 2 = 0.34–0.87). The DRIS and CND indexes were highly related to each other ( R 2 = 0.91–0.99). For N at V4–V6 growth stage, the CND N index was the most closely related to ear yield.