Effect of liming on sulfate transformation and sulfur gas emissions in degraded vegetable soil treated by reductive soil disinfestation Tianzhu Meng 1,2 , Tongbin Zhu 1,2 , Jinbo Zhang 1,2,3,4,5 , Zucong Cai 1,2,3,4,5, ⁎ 1. School of Geography Sciences, Nanjing Normal University, Nanjing 210023, China. Email: mtianzhu@gmail.com 2. Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing 210023, China 3. Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China 4. Key Laboratory of Virtual Geographic Environment (VGE), Ministry of Education, Nanjing Normal University, Nanjing 210023, China 5. Jiangsu Key Laboratory of Environmental Change and Ecological Construction, Nanjing 210023, China ARTICLE INFO ABSTRACT Article history: Received 11 December 2014 Revised 4 March 2015 Accepted 20 March 2015 Available online 10 July 2015 Reductive soil disinfestation (RSD), namely amending organic materials and mulching or flooding to create strong reductive status, has been widely applied to improve degraded soils. However, there is little information available about sulfate (SO 4 2- ) transformation and sulfur (S) gas emissions during RSD treatment to degraded vegetable soils, in which S is generally accumulated. To investigate the effects of liming on SO 4 2- transformation and S gas emissions, two SO 4 2- -accumulated vegetable soils (denoted as S1 and S2) were treated by RSD, and RSD plus lime, denoted as RSD 0 and RSD 1 , respectively. The results showed that RSD 0 treatment reduced soil SO 4 2- by 51% and 61% in S1 and S2, respectively. The disappeared SO 4 2- was mainly transformed into the undissolved form. During RSD treatment, hydrogen sulfide (H 2 S), carbonyl sulfide (COS), and dimethyl sulfide (DMS) were detected, but the total S gas emission accounted for <0.006% of total S in both soils. Compared to RSD 0 , lime addition stimulated the conversion of SO 4 2- into undissolved form, reduced soil SO 4 2- by 81% in S1 and 84% in S2 and reduced total S gas emissions by 32% in S1 and 57% in S2, respectively. In addition to H 2 S, COS and DMS, the emissions of carbon disulfide, methyl mercaptan, and dimethyl disulfide were also detected in RSD 1 treatment. The results indicated that RSD was an effective method to remove SO 4 2- , liming stimulates the conversion of dissolved SO 4 2- into undissolved form, probably due to the precipitation with calcium. © 2015 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. Keywords: Vegetable soil Reductive soil disinfestations Lime Sulfate Sulfur gases Introduction Due to the high economic benefit of vegetables, the cultiva- tion area of greenhouse vegetables has continuously risen to 24.8 million ha, accounting for 14.5% of the farmland in China (Food and Agriculture Organization, FAO, 2013). It is known that intensive vegetable cultivation is characterized by multiple cropping, frequent irrigations and high fertilizer application, which easily lead to soil degradation, such as acidification, salinization, nitrate (NO 3 - ) and sulfate (SO 4 2- ) accumulation, and occurrence of soil-borne diseases (Blok et al., 2000; Cao et al., 2004; Messiha et al., 2007; Zhu et al., 2012). Once the degradation of greenhouse vegetable soils occurs, vegetable yield and economy incomes of farmers decrease significantly. Therefore, JOURNAL OF ENVIRONMENTAL SCIENCES 36 (2015) 112 – 120 ⁎ Corresponding author. E-mail: zccai@njnu.edu.cn (Zucong Cai). http://dx.doi.org/10.1016/j.jes.2015.03.032 1001-0742/© 2015 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. Available online at www.sciencedirect.com ScienceDirect www.journals.elsevier.com/journal-of-environmental-sciences