Influence of liming and form of nitrogen fertilizer on nutrient uptake,growth, yield,and quality of Virginia (flue-cured) tobacco

Soil acidity is a limiting factor affecting the growth and yield of many crops all over the world. It is recognized that liming is the most common management practice of profitable crop production on acid soils. On the other hand, it is well-known that the form of nitrogen may affect tobacco yield and quality. In this work, the impact of the interaction between three hydrated lime (HL, Ca(OH)₂) rates (0, 1.5 and 3 t HL ha⁻¹) and three nitrogen fertilizer forms (NO₃-N 100%, NH₄-N 100% and NO₃-N 50% plus NH₄-N 50%) on growth, yield and quality characteristics of Virginia (flue-cured) tobacco was investigated in a 4-year (1995–1998) field experiment established in an acid soil (pH_{water 1:1} 5.3) located in Northern Greece. Lime was applied only once in December 1994, while nitrogen fertilizer was applied annually before transplanting. The results showed that the effect of liming on tobacco growth was not dependent on time, weather conditions and form of nitrogen fertilizer. Liming increased soil pH, enhanced the early growth of tobacco (within 30 days after transplanting (DAT)) and finally increased the total gross and trade yield of tobacco proportionally to the amount of HL added. However, the quality index (organoleptic characteristics) of the cured product was improved only at the HL application rate of 3 t HL ha⁻¹. Furthermore, liming significantly increased Ca and P concentrations but decreased K concentration in cured tobacco leaves. Tobacco yield increase was attributed to the increase of P uptake. Liming also increased the ash content of cured leaves, whereas it did not significantly affect nicotine, total nitrogen and reducing sugars. The use of ammonium N in fertilizer delayed the early growth of tobacco, reduced the nicotine concentration and increased the reducing sugars concentration of the cured product. Total-N, P, K and Mg concentrations of cured leaves were not significantly affected by the form of nitrogen fertilizer used. The results suggested that an initial application of hydrated lime at a rate of 3 t HL ha⁻¹ may ameliorate soil acidity and increase the yield and quality characteristics of Virginia tobacco at least over a 4-year period after application, independent of the form of N fertilizer used.