Compositional Nutrient Diagnosis (CND) Standards for Opuntia ficus-indica (L.) Miller 'Rojo Pelón' Fruiting

Abstract

In this study, the aim was to develop the compositional nutrient diagnosis (CND) norms for Opuntia ficus indica variety 'Rojo Pelón’ fruiting. Statistical analyses involved a dataset of fruit yield and macro-nutrient concentrations of 228 1-year old cladodes from healthy plants. A cutoff yield (1,166.67 g cladode^-1) between the low- and high-yield subpopulations was determined after examining six cumulative variance ratio functions related to yield per 1-year old cladode. Means and standard deviations of row-centered log-ratios  of five nutrients (N, P, K, Ca, and Mg) and a filling value R_d, which includes all nutrients not chemically analyzed. Estimated preliminary CND norms (mean ± standard deviation of the row-centered log-ratios) are: = ?1.114 ± 0.219, = ?2.194 ±0.076, = 0.163 ± 0.259, = ?0.708 ± 0.157, = 0.401 ± 0.100, and = 3.452 ± 0.095. These CND standards are associated with the following 1-year old fruiting cladode mean concentrations: N=0.958%, P=0.318%, K=3.507%, Ca=4.228%, and Mg=1.448%. Then, the order of macro-nutrient requirements is as follows: Ca>K>Mg>N>P.