Effect of the application of spent flue gas desulfurization absorbent residue on the development of potato gangrene

Abstract

The gangrene of potato (Solanum tuberosum L.) caused by Phoma spp. developed on stored seed tubers (cultivar “Sakurafubuki”) which were harvested from a field with loamy sand soil (Volcanogenous Regosols) in Hayakita, Hokkaido, Japan, in the autumn of 1996. The soil of the area shows a low cation exchange capacity (CEC) and contained less than 500 mg kg −1 of exchangeable Ca, leading to Ca deficiency. On the other hand, spent flue gas desulfurization absorbent residue (SGDAR), which consists of gypsum (CaSO4) and coal ash, had been produced at a power station located near the above-mentioned area, but most of it had been dumped as industrial waste. A field experiment conducted in the area in 1998 showed that the application of SGDAR (10 Mg ha−1) or gypsum (1.6 Mg Ca ha−1) suppressed the development of gangrene on the stored tubers and increased the marketable tuber yield by 27 and 13 %, respectively. As a result of the application of SGDAR or gypsum, the concentration of exchangeable Ca in soil became twice as high as that of the control and the concentration of Ca in the tubers also increased. However, the application of coal ash as boron fertiliser (1.6 kg B ha−1) did not suppress the disease. These results suggest that Ca eluted from gypsum in SGDAR was assimilated by the tubers and increased the resistance of the tubers to the infection with the pathogen.