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With the kind of spring we had, it was pretty predictable that some folks were going to get on their soil too soon. It has come to pass that symptoms are showing up now in crops over that situation. I want to share with you an example based on observations by our tobacco specialist.
Uneven growth of tobacco has been reported in numerous fields. In some fields, plants range in size from nearly 30 inches to less than 6 inches tall. The smaller plants often show signs of nutrient deficiency and may appear to wilt in the heat of the day. When the stunted plants are dug it is often observed that there has been little or no development of new roots from the transplant root ball. New roots if present are often found to be growing from the buried portion of the stem. In many cases the transplant root ball appears folded and somewhat wedge shaped as if it were jammed in a tight space. The obvious question from most growers is why are some plants severely stunted while others a short distance away seem to be thriving.
The answer to that question is a complex interaction between transplant health, soil conditions, and weather at or just after transplanting. Transplants were held for several weeks during the rainy spring weather resulting in tall sometimes spindly plants that often had varying degrees of Pythium root rot. When the weather finally began to dry, growers were anxious to get started and often began prepare ground when it was still too wet. Even though the soil appeared dry on the surface it was still quite moist just below the surface. The bottom of the transplanter shoe running in the moist soil may have created small zone of compacted soil which severely restricted root development from the root ball. In addition stress from high temperatures during early June may have limited the plants’ ability to recover from the setbacks caused by Pythium root rot and soil compaction.
Currently it appears that the stunted plants are recovering as they have begun to develop new roots from the buried stem above the original root ball. The degree of recovery will be very much dependent on the weather conditions. With the majority of the root system very near the soil surface, short term dry spells will be more detrimental and lodging will be a concern as the plants attain a larger size. While many of these plants will survive and perhaps even produce a reasonable yield, the fields will remain very uneven. There is little that can be reasonably done at this stage to help these plants recover. Side dressing, foliar feeding, and irrigation may help to a limited extent to minimize stress, however the stunted plants simply need time to grow new roots.