Farm visits and calls conducted by CTRF indicate that nitrogen deficiency is not uncommon in tobacco this season, which is not surprising considering the excessive rainfall experienced so far. For example, weather data from Environment Canada shows in the Tillsonburg area June brought in a total of 159.4 mm (compared to 88.8 mm normal) and July had 150.2 mm compared to 96.2 mm normal). Moreover, in some cases the rainfall was experienced daily during these two months. Under such conditions, nitrogen losses can occur through soil erosion or leaching below the root zone and soil type impacts the extent of these losses.
Nitrogen (N) is a critical nutrient for producing good yield and leaf quality of flue-cured tobacco. Stunted growth is the first signal for nitrogen deficiency, and is followed by phenotypic symptoms, including pale, green coloration of the lower leaves. Since nitrogen is a mobile element and the plant responds to a deficiency by moving the nutrient away from older leaves to younger leaves, the plant symptoms begin on the older lower leaves and progress up the plant if the deficiency continued. The color will change to a light yellow and will become progressively whiter (Figure.1 &2).
Adding N as a corrective measure is the proper solution considering the plant stage, but soil type and previous crop management must be considered when you are making the decision to apply additional nitrogen to your crop since excessive amounts of nitrogen may show no yield benefit and can reduce cured leaf quality and produce cured leaf with unbalanced chemistry. Other negative consequences may be increasing soil acidity, delayed maturity, and increased weed and sucker problems.
Post prepared and sent by Canadian Tobacco Research Foundation
Mailing Address: CTRF, P.O. Box 322, Tillsonburg, ON N4G 4H5
Telephone: 519-842-8997
Web Address: http://ctrf1.com