Department of Agronomy, University of Agriculture, Jail Road- Faisalabad, Faisalabad, 38000, Pakistan; Carbon Management and Sequestration Center, The Ohio State University, Columbus, OH, 43210, USA.
Carbon Management and Sequestration Center, The Ohio State University, Columbus, OH, 43210, USA; Philippine Rice Research Institute, Maligaya, Science City of Munoz, Nueva Ecija, Philippines.
J Environ Manage. 2019 Oct 15;248:109242. doi: 10.1016/j.jenvman.2019.07.013. Epub 2019 Jul 14.
Synthetic fertilizers are major agents of gaseous emissions including nitrous oxide (NO), and rice cultivation is a primary source of methane (CH) emission. Biochar (BC) addition to agricultural soils is a potential approach to mitigate NO and CH emissions. This greenhouse study was conducted to assess the simultaneous effects of BC and nitrogen (N) fertilization to reduce NO and CH emissions along with higher biomass accumulation in rice under controlled conditions. Nine treatment combinations of BC amendments at 0, 2 and 4% by weight (weight of BC/weight of soil) mixed into 3500 g of unsterile soil with 0, 70 and 140 kg N ha were used in growing rice. Results show that BC-only treatments enhanced the volumetric water contents (VWC) by 9-14% and soil pH by 5-7% coupled with higher daily and cumulative seasonal CH-C fluxes by 85-95% and 48-51%, respectively, compared with control treatment. Under 2% and 4% BC amendments, N at 140 kg ha lowered the daily and cumulative seasonal CH-C fluxes by 24-42% and 20-30%, respectively as compared to 70 kg N ha. Furthermore, BC amendments in N-treated soils reduced the daily and total seasonal NO-N emissions by 27-67% and 49-61%, respectively, relative to N-only treatments. However, N addition in BC-amended soils showed 10-16% decreased VWC compared with the BC-only treated soils. In terms of rice growth, BC-only reduced the above- and below-ground biomass accumulation, delayed the tillering phase, and resulted in fewer vegetative tillers except for BC-treated pots with 140 kg N ha. Thus, this study suggests that the use of BC amendment at 2% with 140 kg N ha may be a beneficial strategy to reduce the net GHG emissions from paddy rice in an Alfisol.
合成肥料是包括一氧化二氮（N2O）在内的气态排放物的主要来源，而水稻种植是甲烷（CH4）排放的主要来源。在农业土壤中添加生物炭（BC）是减少 N2O 和 CH4 排放的一种潜在方法。本温室研究旨在评估在控制条件下，BC 和氮肥同时施用对减少水稻 N2O 和 CH4 排放以及提高生物量积累的综合影响。在种植水稻时，使用了 9 种 BC 施用量（BC 重量/土壤重量）为 0、2 和 4%的处理组合，与未灭菌土壤（3500g）混合，土壤中 N 施用量为 0、70 和 140kg/ha。结果表明，与对照处理相比，仅添加 BC 的处理使土壤的体积含水量（VWC）增加了 9-14%，土壤 pH 值增加了 5-7%，同时使每日和季节性累积 CH-C 通量分别增加了 85-95%和 48-51%。在 2%和 4%的 BC 施用量下，N 施用量为 140kg/ha 时，每日和季节性累积 CH-C 通量分别降低了 24-42%和 20-30%，而 N 施用量为 70kg/ha 时则降低了 24-42%和 20-30%。此外，在施 N 的土壤中添加 BC 减少了每日和总季节性 NO-N 排放量，分别比仅施 N 的处理减少了 27-67%和 49-61%。然而，在施 BC 的土壤中添加 N 会使 VWC 降低 10-16%，与仅施 BC 的土壤相比。就水稻生长而言，仅添加 BC 会减少地上和地下生物量积累，延迟分蘖期，并导致分蘖减少，除了在 140kg/ha 的 N 处理的 BC 处理罐中。因此，本研究表明，在 Alfisol 中，使用 2%的 BC 与 140kg/ha 的 N 相结合可能是减少水稻净温室气体排放的一种有益策略。
