Effect of Removing P.E film-Mulch at Budding Stage of Tobacco on the Change of Moisture and Mineral Content in Plow Layer Soil and Nutrient Uptake.

생육중반기 피복제거가 작토층의 수분 및 무기성분 변화와 연초양분흡수에 미치는 영향

This experiment was carried out to Investigate the environmental changes of rhizosphere, behavior of nutrient components in soul, and nutrients uptake and growth response of the tobacco plant in the condition that mulch as polyethylene film, had been removed on the ridge at the 50th day after transplanting in comparison with continuous mulching condition. The results obtained were as follows; 1. After rainfall, soil moisture content In the plow layer was greatly increased without mulch in comparison with that of the plot with mulch. As a result, leaf water potential of tobacco plant without mulch was higher than that with mulch. 2. Available nutrients such as $NH_4-N, \;NO_3-N$, and total salts in the plow layer of the plot without mulch tended to be Increased, and especially accumulated on the surface layer owing to the redistribution of soil water by rainfall during the latter growth stage after removing mulch. 3. Nutrients uptake by tobacco was much more enhanced in the plot without mulch and resulted in higher contents of total nitrogen, $NO_3-N, \;P_2O_5, \;and K_5O$ in the tobacco leaf Especially higher content of nitrogen caused the delay of maturity resulting In the increased of dry weight of top part of tobacco in the plot without mulch toned to be Increased in comparison with that in mulching condition. Content of total nitrogen, $NO_3-N$, and nicotine in flue-lured leaves was much higher in the plot without. mulch than in mulching condition, but lower content of reducing sugar in the plot without mulch resulted in lower quality of tobacco.