Diagnosing Winter Injury After Soil Thaws [Potential Injury Symptoms]
1. Slow Green-Up: within the field, if portions are green and others remain brown it’s time to check these brown portions.
2. Partial Crown Growth: spring growth is determined the prior fall. Parts of the root [linked to the crown, which initiates buds] can be damaged leaving only a part of the plant viable.
3. Uneven Growth: some buds may be damaged over winter. New buds may be initiated, but these shoots will be shorter than surviving bud shoots.
4. Roots: take a look at the roots by digging them up. Healthy tissue will be white, while damaged tissue will be brown or a dark discoloration. More damage equals less production; roots can be so damaged they rot and the plant will ultimately die.
A few notes:
- Healthy roots should be firm and white. If the root is soft and water can be squeezed from the root, it is likely winterkilled.
- If over half the root is showing discoloration/signs of rot, it will most likely die.
- If less than half the root is showing symptoms of rot, it has a favorable chance for surviving the season [or potentially more than a season].
- Stem density of 55/ft2 has full yield potential. Take density counts after green-up and stand is at least 4” tall.
- Older stands have less plants but those remaining plants will produce more stems; make sure to evaluate STEMS – a field with less than 55 stems/ft2 is a candidate for rotation.
Pioneer Field Facts, VOL. 13, NO. 2