Assessing Soybean Nodulation at R1 (Beginning Bloom)

It's important to assess soybean crops for nodulation in every field, every year. Assess nodulation at R1 to determine if your soybeans have enough nodules for sufficient N-fixation (10 or more per plant, on average). If nodule activity or number is insufficient, consider a rescue N-treatment of 50 lbs N/ac at R2-R3 (full flower to early pod).
1. Use a shovel to dig up roots and soak them in water to remove excess soil without breaking off nodules.
2. Cut nodules open to assess the colour. Pinkish-red nodules are actively fixing N.
Also be on the lookout for lemon-shaped cysts that may be on the roots, caused by soybean cyst nematode. These cysts will be much smaller than root nodules.