What is in this article?:
- Understand, prevent soil compaction or lose tobacco yield
- Limited root system leads to fertility problems
- Soil compaction has become more common in the past several years, as tobacco farms have gotten larger and growers have more acreage to cover.
- As the plant grows, the limited root system physically cannot keep up with the rapid top growth of the plant. Potassium deficiency is most common under these conditions.
- The most common results of the wet 2013 season were yields that were substantially lower than expected.
SOIL COMPACTION has become more common in the past several years, as tobacco farms have gotten larger and growers have more acreage to cover. Tobacco may develop healthy roots laterally from the root ball and from the stem above the root ball with very little downward root growth due to the compacted zone.
Limited root system leads to fertility problems
As the plant grows, the limited root system physically cannot keep up with the rapid top growth of the plant. Potassium deficiency is most common under these conditions, but phosphorus deficiency symptoms may also occur.
During a wet season like 2013, tobacco may even appear to be showing nitrogen deficiency symptoms of yellowing from the bottom of the plant upward. The first reaction of growers seeing these symptoms is to add more nitrogen or more of whatever nutrient appears to be limiting. Most often the deficiency is temporary and the crop recovers over time without additional fertilizer, or the root system is so small that no amount of additional fertilizer would cause significant recovery.
In Kentucky, nitrogen losses should be minimal even in wet seasons when tobacco is grown on soils that are well drained but not too sandy. Adding additional nitrogen, particularly after layby at five weeks or so after transplanting can be more detrimental to the crop than any nitrogen deficiency symptoms, resulting in rank growth later in the season, increased potential for green cured leaf and possible increases in tobacco-specific nitrosamines.
Although some dark tobacco crops in 2013 got severely injured from single large rain events of 6 inches or more, causing tobacco to wilt due to saturated soil conditions and later sunscald, damage this severe was localized in certain areas and many crops showed substantial recovery when injury occurred early in the season.
The most common results of the wet 2013 season were yields that were substantially lower than expected. The ultimate effect of a wet season on tobacco is thin leaf from plants that may look good and feel heavy at harvest, but weigh several hundred pounds per acre less than expected when cured.