Effect of N and P Fertilization on Yield and Quality of Local Tobacco

Abstract

An examination of the effects of N and P fertilization on yield and quality of local tobacco (Nicotiana tabacumL.) was made in late wet-season sowings (October/November) in 1981. the experiments were undertaken at two sites, a farmer's field (Low-Humic Gley soils) in Song district of Prae Province and at the Supanburi field Crops Research Center (Noncalcic Brown soils) of the department of Agriculture. At each site, the available P level was less than 55 ppm, whereas OM was 1.7 to 2.2% Three rates of N fertilizer (o, 4, and 8 kg N/rai) and three rates of P fertilizer (o, 20, and 40 kg N/rai) were compared in a 3 x 3 factorial experiment with four replications. A base application of K was given to all treatments at a rate of 25 kg K,O/rai. An application of 4 kg/rai of N increased tobacco yield by an average of 13 to 33% (161-180 kg/rai) when compared with the O kg/rai nitrogen treatment (121-159 kg/rai) ; tobacco quality also remained acceptable. The optimum level of phosphate (P2O5) application was 20 kg/rai rai in response to which there was an improvement in tobacco quality and a 0.7 to 7% increase in yield. The results were consistent at both experimental sites.