Nutrient Uptake, Partitioning, and Remobilization in Modern, Transgenic Insect-Protected Maize Hybrids

Modern maize (Zea mays L.) hybrids coupled with improved agronomic practices may have influenced the accumulation and partitioning of nutrient uptake since the last comprehensive studies were published. The objective of this study was to investigate nutrient uptake and partitioning among elite commercial germplasm with transgenic insect protection grown under modern management practices. Plants were sampled at six growth stages and divided into four fractions for nutrient determination. Total nutrients required per hectare to produce 23.0 Mg ha(-1) of total biomass with 12.0 Mg ha(-1) of grain included 286 kg N, 114 kg P2O5, 202 kg K2O, 59 kg Mg, 26 kg S, 1.4 kg Fe, 0.5 kg Mn, 0.5 kg Zn, 0.1 kg Cu, and 0.08 kg B. A 10-d period (V10-V14) denoted the maximum rates of accumulation on a per day basis for dry weight (439 kg), N (8.9 kg), P2O5 (2.4 kg), K2O (5.8 kg), Mg (2.2 kg), S (0.7 kg), Zn (14.2 g), Mn (18.0 g), B (3.3 g), Fe (95.3 g), and Cu (3.0 g). The majority of total uptake occurred post-flowering for P, S, Zn, and Cu. Harvest index values of P (79%), S (57%), Zn (62%), and N (58%) were identified in the grain. These results provide much needed data on the nutrient uptake and partitioning of current hybrids, and provide an opportunity to further refine fertilizer method and timing recommendations for maize biomass and grain production.