Dry Matter and Nitrogen Uptake, Partitioning, and Removal across a Wide Range of Soybean Seed Yield Levels

• DOI: 10.2135/cropsci2016.05.0322
• Publication Date: 2017-05-25T19:41:16Z
• Authors: Adam P. Gaspar; Carrie A.M. Laboski; Seth L. Naeve; Shawn P. Conley
• Keywords: Growing season; Dry weight

Soybean [ Glycine max (L.) Merr.] growers are concerned that soybean yield is restricted by limitations on biological N 2 fixation and soil nitrogen (N) mineralization. However, a comprehensive study characterizing actual requirements across wide‐ranging seed environments nonexistent for modern production systems. Using six site‐years eight varieties, plants were sampled at growth stages partitioned into their respective plant parts analyzed. For each kilogram increase in yield, total dry matter accumulation, harvest index, uptake increased 1.45 kg, 0.0034%, 0.054 respectively, but all varied environment any specific level, whereas removal did not (0.055 kg −1 grain). Nitrogen index (NHI) (0.0019–0.004% grain) with resulting indices between 73 90%. Peak rates 3.6 to 4.3 ha d R4 R5, depending the level. After R5.5, 66 69% of vegetative was remobilized seed, which accounted 50.4% low level (3608 ), only 38.9% high (5483 ). Moreover, higher yields attained greater portion after R5.5 (40.1%) compared (29.7%). These results highlight remobilization efficiencies late‐season conjunction NHI support per unit current realities.