Manure, biogas digestate and crop residue management affects methane gas emissions from rice paddy fields on Vietnamese smallholder livestock farms

• Published in: Nutrient cycling in agroecosystems 2015-12, Vol.103 (3), p.329-346
• Main Authors: Vu, Quynh Duong, de Neergaard, Andreas, Tran, Toan Duc, Hoang, Quan Quang, Ly, Proyuth, Tran, Tien Minh, Jensen, Lars Stoumann
• Format: Article
• Language: English
• Subjects: Agriculture; biochar; Biogas; Biomedical and Life Sciences; Cereal crops; Charcoal; composted manure; Composting; Crop management; crop residue management; Crop residues; Crop yield; Crops; detection limit; Emissions; Farm buildings; Farms; field experimentation; Fluxes; grain yield; Greenhouse effect; greenhouse gas emissions; Greenhouse gases; Life Sciences; Livestock; Livestock farming; Manures; Methane; Mineral fertilizers; nitrogen fertilizers; Nitrous oxide; Original Article; Oryza; paddies; Rice; Rice fields; Rice straw; Seasons; Soil degradation; Spring; Spring (season); Straw; Summer
• ISSN: 1385-1314; 1573-0867
• DOI: 10.1007/s10705-015-9746-x

Greenhouse gas (CH₄ and N₂O) emissions from rice paddy fields amended by differently treated manure and crop residue inputs [fresh manure (FM), composted manure (CM), liquid biogas digestate from manure (D), D mixed with biochar (D + B) or D mixed with rice straw and composted before application (CD + RS)], were compared in a field experiment, also including two mineral nitrogen fertiliser controls (N1, N2). The trial was performed on a degraded soil in Bac Giang Province in northern Vietnam with a three-crop per year rotation (summer rice–maize–spring rice). CH₄ and N₂O fluxes from the two rice crops were measured using static chambers. Fluxes of N₂O were below or close to the detection limit at nearly all sampling times in both seasons and therefore considered negligible. However, the CH₄ emissions were significant and their temporal pattern differed markedly between the rice seasons. In the summer rice season, the D + B + N1 and D + N1 treatments had significantly lower cumulative CH₄ emissions (156 and 162 kg CH₄ ha⁻¹ crop⁻¹) than CM + N1, CD + RS + N1 and FM + N1 treatments (217, 283 and 288 kg CH₄ ha⁻¹ crop⁻¹, respectively). In the spring rice season, CH₄ emissions were generally much lower, and the D + B + N1 and D + N1 treatments emitted significantly less CH₄ (44 and 72 kg CH₄ ha⁻¹ crop⁻¹) in comparison with treatments amended with FM + N1, CD + RS + N1 and CM + N1 (89, 124 and 137 kg CH₄ ha⁻¹ crop⁻¹, respectively). Treatments amended with D + B + N1 or D + N1 therefore had the lowest emissions of methane per unit of rice grain yield.