Effects of levels and forms of phosphate fertilizers on flue cured virginia tobacco in Kelantan

A.C Leong

Abstract

56.1 kg ha^-1 phosphate was sufficient for both the alluvial and Sandy Bris as no significant differences were detected between the other levels. Similarly no difference was detected between the forms of phosphate in terms of yield as 25% TSP yielded non-significantly from 100% TSP in second season. In the fourth season the forms of phosphate was critical as 50% TSP : 50%, CIRP  and 100% TSP yielded significantly higher than 25% TSP : 75% CIRP. The treatment with 50% TSP : 50% CIRP provided a readily and consistent supply of PO₄ and is superior to 100% TSP. Based on quality of the tobacco leaves especially the percent sugar and nicotine it was found that beyond ll2.l kg P₂O₅, ha^-1 applied caused a significant depression in percent sugar on alluvial soil. No significant difference was detected between 56.1 and 112.1 kg P₂O₅ ha^-1 in the percent sugar. It was also shown that 100% TSP was detrimental to the leaf quality as it recorded a significantly lower percent sugar than the 25% TSP : 75% CIRP and 50% TSP : 50% CIRP. This confirmed the importance of lower dosage < 112.1 kg P₂O₅ ha ^-1 applied in the form of a readily and consistent source of PO₄.as in 50% TSP : 50% CIRP on alluvial soil. On the Sandy Bris soil no individual treatment except the treatments combination gave any significant difference in the percent sugar. On differentiating the multiple regression equations for the percent sugar on both Sandy Bris and alluvial soil the technical optimum level and form of phosphate was obtained approximately. to the treatment of 112.1 kg P₂O₅, ha^-1  applied as 50% TSP : 50% CIRP. On Sandy Bris 56.1 kg  P₂O₅ ha^-1  recorded a significantly lower percent nicotine than 140.1 and 168.1 kg.P₂O₅ ha^-1 though no significant difference was detected between 84.1 kg P₂O₅ ha^-1 and 168.1 kg P₂O₅ ha¹¹. Leaf quality is very important in tobacco culture. From the experimental data the  leaves from Sandy Bris and alluvial soil in Kelantan still has a very low range of percent sugar and nicotine compared to the leaves from USA. Though there was no significant difference between 56.1 and 112.1 kg P₂O₅,ha^-1 the latter had a higher percent sugar. nicotine and sugar/nicotine ratio. Thus based on yield the level of PO₄ suggested is 56.1 kg P₂O₅ ha^-1 applied as 50% TSP : 50% CIRP however, in terms of leaf quality it appeared that 112.1 kg P₂O₅ ha^-1 applied as 50% TSP: 50% CIRP is a better level for the tobacco culture on both soil types.

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