간척지 논 토양 개량제로서 석고처리가 메탄 배출량 저감에 미치는 영향

Abstract

BACKGROUND: Gypsum(CaSO_4ㆍ2H_2O) is known as an ideal amendment to improve soil quality of the reclaimed coastal land. Since gypsum has very high concentration of electron acceptor like SO_4^(2-), its application might be effective on reducing CH_4 emission during rice cultivation, but its effect has not been studied well. METHODS AND RESULTS: The effect of gypsum on CH_4 emission and rice growth characteristics was studied by pot test, which was packed by reclaimed paddy soils collected from Galsa, Hadong, Gyeongnam province. Chemical-grade gypsum was applied in two soils having EC 2.25 and 9.48 dS/m at rates of 0, 0.5, 1.0 and 2.0%(wt/wt). CH_4 emission was characterized a week interval by closed chamber method during rice cultivation. CH_4 emission rate was significantly decreased with increasing salt accumulation and gypsum application levels. With increasing gypsum application, dissolved SO_4^(2-) concentration in the leachate water was significantly increased, which might have suppressed CH_4 production in soil. Total CH_4 flux was dramatically decreased with increasing gypsum application. In contrast, rice yield was increased with increasing gypsum application and then achieved maximum productivity at 1.0% gypsum application in two soils. CONCLUSION(s):Gypsum is a very good soil amendment to suppress CH_4 emission in reclaimed coastal paddy soils, and improve rice productivity and soil properties. The optimum application level of gypsum is assumed at ca. 1% to improve soil productivity with reducing effectively CH_4 emission during rice cultivation.