Absorption, partitioning, and export of nutrients by phenological stage in maize cultivated in Eastern Maranhão, Brazil

Abstract

This study aimed to evaluate the absorption, partitioning, and redistribution of nutrients by phenological stage of the maize crop, under the edaphoclimatic conditions of the municipality of Brejo, Maranhão, Brazil. The experiment was carried out in a Yellow Argisol, under a randomized block design, with seven treatments corresponding to the phenological stages V5, V8, VT, R1, R3, R5, and R6, and four replicates. The plant was partitioned into leaves, stalk, reproductive organs (tassel, straw, cob), and grains to determine the concentrations of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn. The accumulation of nutrients in each organ in the different phenological stages was estimated based on the values of dry weight and nutrient concentrations. A slow accumulation of dry weight was observed in the maize plant until the flowering stage (VT), a pattern also observed for the nutrients P, Mg, S, and Cu. Nutrients N, K, Ca, B, Fe, Mn, and Zn showed values close or superior to 50% of the maximum accumulated up to VT. The decreasing order of nutrient accumulation was N > K > P > Mg > S>Ca > Fe > Zn > Mn > Cu > B. The nutrients with the highest harvest rates were P > N > Mg > S>Zn (0.84, 0.74, 0.72, 0.69, and 0.51, respectively). N, K, Ca, B, Zn, Fe, and Mn are the most absorbed nutrients in the initial stage of crop development. The nutrients that are absorbed in greater quantity after flowering are P, S, Mg, and Cu. The degrees day sum showed no effects on the maize crop cycle under the edafoclimatic conditions of this study.