Methane and nitrous oxide emissions in the rice-shrimp rotation system of the Vietnamese Mekong Delta
Huynh Van Thao,
Nguyen Van Cong,
Le Thi Cam Nhung,
Tran Hoang Kha,
Huynh Cong Khanh,
Le Van Dang,
Nguyen Phuong Duy,
Huynh Quoc Tinh,
Trieu Nguyen Lan Vi,
Nguyen Phuong Chi,
Tran Sy Nam
Affiliations
Huynh Van Thao
Department of Environmental Sciences, College of Environment and Natural Resources, Can Tho University, 3/2 street, Can Tho city, 900000, Viet Nam; United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu city, 183-8538, Tokyo, Japan
Nguyen Van Cong
Department of Environmental Sciences, College of Environment and Natural Resources, Can Tho University, 3/2 street, Can Tho city, 900000, Viet Nam
Le Thi Cam Nhung
Western Highlands Agriculture and Forestry Science Institute, Buon Ma Thuot city, Dak Lak, 630000, Viet Nam
Tran Hoang Kha
Department of Environmental Sciences, College of Environment and Natural Resources, Can Tho University, 3/2 street, Can Tho city, 900000, Viet Nam
Huynh Cong Khanh
Department of Environmental Sciences, College of Environment and Natural Resources, Can Tho University, 3/2 street, Can Tho city, 900000, Viet Nam; Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki city, 852-8521, Japan
Le Van Dang
United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu city, 183-8538, Tokyo, Japan; College of Agriculture, Can Tho University, Can Tho city, 900000, Viet Nam
Nguyen Phuong Duy
WWF-Vietnam, No. 6, Lane 18, Nguyen Co Thach Street, Nam Tu Liem District, Ha Noi, 100000, Viet Nam
Huynh Quoc Tinh
WWF-Vietnam, No. 6, Lane 18, Nguyen Co Thach Street, Nam Tu Liem District, Ha Noi, 100000, Viet Nam
Trieu Nguyen Lan Vi
WWF-Vietnam, No. 6, Lane 18, Nguyen Co Thach Street, Nam Tu Liem District, Ha Noi, 100000, Viet Nam
Nguyen Phuong Chi
Department of Environmental Sciences, College of Environment and Natural Resources, Can Tho University, 3/2 street, Can Tho city, 900000, Viet Nam
Tran Sy Nam
Department of Environmental Sciences, College of Environment and Natural Resources, Can Tho University, 3/2 street, Can Tho city, 900000, Viet Nam; Corresponding author.
Rice-shrimp rotation systems are one of the widespread farming practices in the Vietnamese Mekong Delta coastal areas. However, greenhouse gas (GHG) emissions in the system have remained unclear. This study aimed to examine methane (CH4) and nitrous oxide (N2O) emissions from the system, including (i) land-based versus high-density polyethylene-lined (HDPE) nursery ponds and (ii) conventional versus improved grow-out ponds inoculated with effective microorganisms (EM) bioproducts. The results showed that CH4 flux in land-based and HDPE-lined nursery ponds were 1.04 and 0.25 mgCH4 m−2 h−1, respectively, while the N2O flux was 8.37 and 6.62 μgN2O m−2 h−1, respectively. Global warming potential (GWP) from land-based nursery ponds (18.3 g CO2eq m−2) was approximately 3 folds higher than that of the HDPE-lined nursery pond (6.1 g CO2eq m−2). Similarly, the mean CH4 and N2O fluxes were 15.84 mg CH4 m−2 h−1 and 7.17 μg N2O m−2 h−1 for the conventional ponds, and 10.51 mg CH4 m−2 h−1 and 7.72 μg N2O m−2 h−1 for the improved grow-out ponds. Conventional practices (2388 g CO2eq m−2) had a higher 1.5-fold GWP compared to the improved grow-out pond (1635 g CO2eq m−2). The continuation of the land-based nursery pond and conventional aquacultural farming practices increase CH4 emission and GWP, while applying HDPE-lined nursery ponds combined with improved grow-out ponds could be a promising approach for reducing GHG emissions in rice-shrimp rotation systems. This study recommends further works in the rice-shrimp rotation systems, including (i) an examination of the effects of remaining rice stubbles in the platform on the availability of TOC levels and GHG emissions and (ii) ameliorating dissolved oxygen (DO) concentration on the effectiveness of GHG emission reduction.
