Cotton

Boron Deficiency

Boron deficiency is perhaps wrongly accused of more problems than any other nutrient. Boron is very water soluble and deficiency is related to soil type, soil resource regions, organic matter content and timing of lime materials (pH). Symptoms are generally distinct, and descriptions of this disorder are quite similar across a larger range of environments. Petioles of younger leaves will be short and thick, with dark concentric bands along their length. It appears that the gossypol glands line up and arrange themselves in a "coon tail" arrangement. Flowers may also be distorted in shape. With severe boron deficiency, the terminal may be aborted or become deformed. The pith inside petioles of leaves or bolls may turn brown. Boron is required for normal flower development. Flower and boll shedding may increase as the level of deficiency increases.

Local University and Extension recommendations for boron applications should be followed closely. Some states recommend larger quantities of boron than others. In Misssissippi boron is recommended on hill area soils, recently limed soils and low organic matter sandy soils of the Delta. Generally the Delta region does not respond to boron. Sometimes irrigation water will contain sufficient levels of boron. Not all square, flower or boll shedding is due to boron deficiency problems. Follow your local recommendations with this micronutrient.