Abstract
Experiments were carried out to reveal the differences of rainfall interception due to the canopy of various tobacco varieties. Four varieties, Burley 21 (conical plant with standing leaves), Mito 3 (conical plant with drooping leaves), Bright Yellow (conical plant with intermediate leaf type) and Enshu (cylindrical plant with intermediate leaf type) were selected for this study. The rainfall run down along the stipules and stalks was measured by using catchment basins each of which with a funnel shaped collar attached to the stalk by paraffin. Canopy penetration under tobacco plant was measured by means of gutters made of vinyl chloride, 10cm wide and 1m long, which had been arranged on the ground over whole width of inter row spacing. Soil moisture was determined by a tension meter. 1) The amount of ground rainfall which fell to the center of the interspace was different by varieties and largest amount was found in the field of Mito 3. 2) More than twice as much precipitation falls in the center of the interspace than in the adjacent parts of the row space. 3) A part of the rainfall was conducted to the ground along the stipules and the stalks. This amount, which varied by varieties as that had been observed in the ground rainfall, was the largest in the field of Burley 21. 4) The soil moisture in the inter row spacing of the field on which Mito 3 is grown has a tendency to be lower than that in the field of Burley 21. 5) Thus the distribution of ground rainfall was influenced by the character of vegetative canopy and appeared to contribute to the specific growth of plant.
