Foliar Nutrient Balance Standards for Maize (<i>Zea mays</i> L.) at High-Yield Level

Abstract

Maize is one of the most nutrient demanding staple crops. Tissue nutrient diagnosis of maize is currently conducted using critical nutrient concentration or dual ratio ranges, but such diagnoses are pathological as biased by data redundancy, sub-compositional incoherence and non-normal distribution. The use of orthogonal balances, a compositional data analysis technique, avoids such biases. Our objective was to develop foliar nutrient balance standards for maize. We collected 758 grain yields (15.5% moisture content) and foliar samples at silk stage in maize fields of southern Quebec, Canada, and analyzed ten nutrients in tissues (N, P, K, Ca, Mg, B, Cu, Zn, Mn, Fe). Nutrients were arranged into ad hoc balances and computed as isometric log ratios (ilr). An optimized binary classification performed by a customized receiver operating characteristic procedure showed that a critical Mahalanobis distance of 4.21 separated balanced from imbalanced specimens about yield cut-off of 11.83 Mg grain·ha −1 with test performance of 86%. Quebec maize balance standards differed from published standards computed from DRIS norms collected in other agroecosystems. The Redfield N/P ratio in maize leaves was found to be the least variable balance across regions of the world. The DRIS dual ratios and raw concentration values were found to be geometrically inadequate for conducting diagnosis. The unbiased nutrient balance diagnosis combined the critical Mahalanobis distance and a mobile representation of nutrient balances with ilr means of true negative (TN) specimens centered at fulcrums and back-transformed ilr values of TN specimens into raw concentrations loading the buckets below. Nutrients can be appreciated as relative shortage, adequacy or excess in the concentration domain following statistical analysis and diagnosis in the unbiased balance domain.

Investigating the Balance Status of Nutrients in Wheat Plant Using Isometric Log Ratio and Field Validation of Balances

“…Walworth and Sumner (1987) and Marschner (1995) stated that suitable ratio among nutrients cannot be an efficient criterion for diagnostic purposes since identifying the appropriate levels of nutrients for determining excess, adequate, or deficient level is impossible in the ratio. The DRIS has incomplete geometry because its results are affected by how to choose the dual ratio expression, non‐additivity of functions and indices, and having extra degree of freedom (Modesto et al, 2014). The DRIS were shown to be methodologically biased from compositional model in several studies such as Parent et al (2013a, 2015) and Modesto et al (2014).…”

“…The DRIS has incomplete geometry because its results are affected by how to choose the dual ratio expression, non‐additivity of functions and indices, and having extra degree of freedom (Modesto et al, 2014). The DRIS were shown to be methodologically biased from compositional model in several studies such as Parent et al (2013a, 2015) and Modesto et al (2014). The DRIS geometry reformed using the centered log ratio (CLR), but the CLR is influenced by abnormally high or low concentration in some components such as micronutrients used in fungicide (Filzmoser et al, 2009).…”

“…In plant nutrition, in which log contrasts are defined for the corresponding balances of nutrients. The CND-ilr method has been used for studying the composition and balance of several crops (Parent, 2011;Parent et al, 2012;Hernandes et al, 2012;Marchand et al, 2013;Parent et al, 2013a, Modesto et al, 2014. However, application of such a method has not been reported for wheat in the literature.…”

Optimizing soil and water management in dryland farming systems in Cabo Verde

“…Table 4.2 for treatment descriptions. ** Sufficiency range is 25-35 g kg -1 for N and 2.5-4.0 g kg -1 for P (Modesto et al, 2014). Rf, rainfall; Bm, biomass; MY, maize yield; TN, total N loss; TP, total P loss; Rn, runoff; Sd, sediment loss; Sl, slope; M, soil moisture.…”

“…The N content of the plant tissues was below the sufficiency level (Steinhilber & Salak, 2010) in all treatments at all sites, but the P content was at or above the sufficiency level in all treatments at all sites. Maize is a nutrient-demanding staple crop, so symptoms of deficiency appear and grain yield and quality decline when N levels drop below the sufficiency range (Modesto et al, 2014). N is a limiting nutrient in dryland maize in Cabo Verde (INIDA, 1997), and deficiency symptoms are widespread on the hillsides.…”