Boundary line and mathematical chance in determining nutritional status in the pitaya

Abstract

The aim of this study was to evaluate, using the boundary line method and mathematical chance, the nutritional status of pitaya subjected to combinations of increasing doses of nitrogen-potassium (N-K) and phosphorus-zinc (P-Zn). Five doses of N (0, 150, 300, 450 and 600 mg dm-3) and K (0, 75, 150, 225 and 300 mg dm-3) were applied in experiment I, and five doses of P (0, 75, 150, 255 and 300 mg dm-3) and Zn (0, 2, 4, 6 and 8 mg dm-3) in experiment II. Both experiments were arranged in a 5 × 5 factorial scheme of four randomised blocks. There was ample similarity between the sufficiency ranges obtained with mathematical chance and the boundary line method, except for phosphorus. Sufficiency ranges obtained using the boundary line method were broader than those obtained by mathematical chance. The boundary line method is highly predictive in adjusting the data, proving to be an important tool for obtaining sufficiency ranges and reference values for further studies into nutritional diagnosis in the pitaya.