Fertilizer Placement Effects on Growth, Yield, and Chemical Composition of Burley Tobacco1

Abstract

AbstractApplication of high rates of commercial fertilizers to burley tobacco (Nicotiana tabacumL.) soils through commonly used broadcast methods increases the osmotic pressure of the soil solution and soil acidity. Such changes in the soil may result in damage to plant roots, nutrient toxicities and deficiencies, delayed growth and maturity, and reduced yields. The current study was conducted to determine the influence of placing N and K fertilizers in bands of varying width between rows on selected chemical characteristics of soil (Maury silt loam, clayey, mixed mesic, Typic Paleudalf) and on growth, yield, and chemical composition of burley tobacco, cv. Ky‐14. Field experiments were conducted during 1979 to 1980 at two locations. Treatments consisted of 840 kg NH4NO3ha−1and 672 kg K2SO4ha−1applied either broadcast or in bands 80, 60, 40, and 20 cm wide centered between rows. Plant samples were taken at 45 days, and after maturity and curing for growth, yield, and chemical analysis. Surface soil pH depression in the row decreased as distance of the fertilized band from the row increased and pH in rows of the 20 cm band treatment remained about 0.3 to 0.5 pH units higher throughout the season than in broadcast treatments. The reverse was true for soil pH in the fertilized bands, with the 20 cm band treatment having lowest pH. Placement of the fertilizer in bands away from the row resulted in decreased electrical conductivity of the soil solution in the row, in decreased DTPA‐extractable Mn in the row, lower concentration of plant Mn and K, and fewer days to flower. In contrast, banding increased plant dry weight (21 to 40%) and plant Mg concentration at 45 days, cured leaf yields (9%), value per ha, and cured leaf alkaloid concentration.