Jim Specht - Emeritus Professor of Agronomy

Impact of R Stage-timed Single Irrigation Events on Soybean Seed Number and Seed Mass

October 11, 2023

Results of a three-year study investigating the impact of mitigating water stress during soybean reproductive stages on the two components that comprise yield — seed number and seed mass.

Post-harvest Measurement of Soybean Seed Number and Seed Mass Contributions to Final Seed Yield

October 11, 2023

Learn more about the process of comparing pre-harvest soybean yield estimates with post-harvest yield outcomes.

Hail Damage to Soybean in Reproductive Stages and Options

July 14, 2023

Nebraska Extension educators and specialists share replant recommendations for soybean producers recently affected by hailstorm damage.

Frost damaged sorghum — If sorghum is at hard dough stage when temperatures dip to 28°F for a period of two hours, it may result in a yield reduction of around 20%.

Premature Frost Damage to Crops

October 14, 2022

UNL experts weigh in on the potential impacts for replant crops that experienced freezing temperatures Oct. 8 or may be at risk for a freeze this weekend.

Figure 1. Soybean pods collected from stage R7 plants (one mature pod per plant) that were opened to determine if the pod wall interior membrane was still clinging tightly to the seeds (leftmost pod), or if it was beginning to detach from the seeds (second pod), or if the membrane was now permanently attached to the pod wall (third pod). After attaining physiological maturity, seeds undergo a dry-down period from about 60% moisture to about 13% moisture. Note that the Rx.x numbers used here are pod-based stages, not plant-based stages.

Understanding Ending Reproductive Stages in Soybean

August 27, 2021

The timing of the ending R stages in soybean is governed by planting date (PD) and varietal maturity group (MG), though the date of R7 can be hastened if water stress and high temperatures prevail in August — something we are seeing in portions of Nebraska this year.