Yu Shan, Xue Li-Hong, Hua Yun, Li De-Tian, Xie Fei, Feng Yan-Fang, Sun Qing-Ye, Yang Lin-Zhang
College of Resources and Environmental Engineering, Anhui University, Hefei 230601, China.
Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
Huan Jing Ke Xue. 2020 Feb 8;41(2):922-931. doi: 10.13227/j.hjkx.201908026.
Hydrochar, as a product of the hydrothermal carbonization of biomass, has good application prospects for the NH volatilization reduction in rice fields due to its rich pore structure and functional surface. In this study, hydrochar was applied as a soil conditioner to paddy soil. A soil column experiment was conducted to investigate the effect of hydrochar on NH volatilization throughout the growth period of rice. The experiment was conducted with three treatments:CKU (control without hydrochar); SHC (sawdust hydrochar); and W-SHC (water-washed sawdust hydrochar). The application rate of SHC and W-SHC was 0.5% (). The study investigated the effects of different hydrochars on the pH and concentrations of NH-N in floodwater, the flux and accumulation of NH volatilization, and the yield-scale cumulative emission of NH volatilization. Results show that the SHC treatment significantly reduces cumulative emissions of NH volatilization and the yield-scale cumulative emissions of NH volatilization (<0.05), which were 32.42% and 47.61% lower than CKU, respectively. The effect of W-SHC on ammonia volatilization reduction was slightly weaker, as the cumulative emissions of NH volatilization and the yield-scale cumulative emissions of NH volatilization decreased by 10.14% and 27.71%, respectively, compared with CKU. The NH volatilization reduction was possibly related to the disturbance of pH and the decrease in NH-N concentrations in the floodwater because of the application of hydrochar. Compared with CKU, both SHC and W-SHC treatments reduced the pH and NH-N concentration in the floodwater. The impacts were more obvious in the rice base fertilizer period (BF) and the first supplemental fertilizer period (SF1) than in the second supplemental fertilizer period (SF2). The soil urease activity was significantly inhibited by hydrochar (<0.05), and the abundance of soil ammonia-oxidizing gene (AOA, AOB) also significantly increased after application of SHC (<0.05). This resulted in the enhanced efficiency of ammonia-oxidizing, which had an effect on the reduction of the NH-N concentrations in the floodwater. This study provides theoretical and experimental data support for the application of hydrochar in agro-environments with regard to ammonia volatilization reduction in paddy fields.
生物质水热碳化产物生物炭，因其丰富的孔隙结构和功能表面，在稻田减少氨挥发方面具有良好的应用前景。本研究将生物炭作为土壤改良剂施用于稻田土壤。通过土柱试验研究生物炭对水稻全生育期氨挥发的影响。试验设置三个处理：CKU（不施生物炭对照）；SHC（锯末生物炭）；W-SHC（水洗锯末生物炭）。SHC和W-SHC的施用量均为0.5%（质量分数）。研究了不同生物炭对稻田水pH值和铵态氮浓度、氨挥发通量和累积量以及产量尺度氨挥发累积排放量的影响。结果表明，SHC处理显著降低了氨挥发累积排放量和产量尺度氨挥发累积排放量（P<0.05），分别比CKU低32.42%和47.61%。W-SHC对氨挥发的减排效果稍弱，与CKU相比，氨挥发累积排放量和产量尺度氨挥发累积排放量分别降低了10.14%和27.71%。氨挥发减少可能与生物炭施用导致的pH值扰动和稻田水铵态氮浓度降低有关。与CKU相比，SHC和W-SHC处理均降低了稻田水的pH值和铵态氮浓度。在水稻基肥期（BF）和第一次追肥期（SF1）的影响比第二次追肥期（SF2）更明显。生物炭显著抑制了土壤脲酶活性（P<0.05），施用SHC后土壤氨氧化基因（AOA、AOB）丰度也显著增加（P<0.05）。这导致氨氧化效率提高，对降低稻田水铵态氮浓度有作用。本研究为生物炭在稻田氨挥发减排农业环境中的应用提供了理论和实验数据支持。
