Nutrient Uptake, Partitioning, and Remobilization in Modern Soybean Varieties

Abstract

The absence of recent data regarding the nutritional needs of modern soybean [Glycine max (L.) Merr.] production systems necessitates a greater comprehensive understanding of nutrient uptake, partitioning, and remobilization. The objective of this study was to evaluate macro‐ and micronutrient accumulation and partitioning in current soybean cultivars. Across 3 site‐years, plants were sampled at seven growth stages and divided into four plant tissue fractions for quantification of nutrient uptake. Accumulation (per ha) of 275 kg N, 21 kg P (48 kg P2O5), 172 kg K (207 kg K2O), 113 kg Ca, 50 kg Mg, 19 kg S, 335 g Zn, 371 g Mn, 325 g B, 849 g Fe, and 63 g Cu were required to produce approximately 3500 and 9500 kg ha−1 of grain and total biomass, respectively. Supplemental fertility modestly increased biomass and yield (2%), but did not alter nutrient partitioning or harvest index. Nutrients with high harvest index (i.e., percentage of total nutrient accumulation partitioned to grain) values included P (81%), N (73%), Cu (62%), and S (61%), which may serve as a limitation to high yield. Seasonal patterns of nutrient accumulation suggested that K and Fe were acquired primarily during late vegetative growth while the uptake of N, P, Ca, Mg, S, Zn, Mn, B, and Cu were more equally distributed between vegetative and seed‐filling growth phases. These results document the rate and duration of macro‐ and micronutrient accumulation in soybean, and highlight the importance of adequate nutrient availability during key crop growth periods.