Effcts of different cutting-roots and K top-dressing measures at later growth stage on K-oncentration in leaves of fluecured tobacco plants in Yunnan Province

The effects of different cutting-roots and K top-dressing measures at later growth stage on K concentration in 1eaves of flue-cured tobacco plants were studied The results demonstrate that cutting-root and increasing application of K can stimulate the formation of new roots and then their uptake activity Cxmsidering both the K content and the leaf dry weight，the best measure is cutting-roots on the position 20 cm away from the stem base and simultaneously the top-dre-ssing with K₂SO₄ when plants are decapitated．