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This article in AJ

  1. Vol. 93 No. 4, p. 809-814
     
    Received: Aug 10, 2000
    Published: July, 2001


    * Corresponding author(s): leon-etienne.parent@sga.ulaval.ca
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doi:10.2134/agronj2001.934809x

Critical Compositional Nutrient Indexes for Sweet Corn at Early Growth Stage

  1. Lotfi Khiaria,
  2. Léon-Étienne Parent *a and
  3. Nicolas Tremblayb
  1. a Dep. of Soil Sci. and Agri-Food Eng., Laval Univ., Paul-Comtois Building, Sainte-Foy, QC, Canada G1K 7P4
    b Hortic. Res. and Dev. Cent., 430 Gouin Blvd., St-Jean-sur-Richelieu, QC, Canada J3B 3E6

Abstract

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.

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Copyright © 2001. American Society of AgronomyPublished in Agron. J.93:809–814.