식물 내건성 평가를 통한 제지 슬러지의 옥상녹화 이용 가능성 연구

The purpose of this study was to find out the possibility of paper mill sludge application for green roof by assessing drought tolerance of Hosta longipes with five different mixing ratio of paper mill sludge and horticultural substrate (9:1, 7:3, 5:5, 3:7 and 1:9). From August 11th to September 29th, number of leaves, plant height, leaf size, chlorophyll content, volumetric water content, evapotranspiration, and relative water content (RWC) were measured. As results, 9:1 was reached 0% of volumetric water content earliest and withered earliest on 35th day of unirrigated experiment, and 7:3 was withered on 42th day. All other mixing ratios were withered on 43th day or later. As for chlorophyll content, all mixing ratios steadily decreased and showed similar patterns. Number of leaves and leaf size were very stable for 21 days and then rapidly decreased. Soil moisture reduction patterns were almost same and evapotranspiration reduction was directly proportional to ratio of horticultural substrate. In conclusion, 50% or less of paper mill sludge application does not significantly affect drought tolerance of H. longipes so that paper mill sludge can be used as substrate for green roof.