Hu Wang, Zhao Hang, Zhou Xuan, Wang Yi-Zhe, Zhang Han-Feng, Zhang Yu-Ping
College of Resources and Environment/Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Agricultural University, Changsha 410128, China.
Institute of Soil and Fertilizer, Hunan Academy of Agricultural Sciences, Changsha 410125, China.
Ying Yong Sheng Tai Xue Bao. 2022 Jul;33(7):1919-1926. doi: 10.13287/j.1001-9332.202207.031.
The application of straw biochar in farmland in Dongting Lake area can realize the resource utilization of straw and reduce environmental risk. In 2020, a rice pot experiment was conducted to investigate the effects of different biochar application levels on ammonia volatilization rate, cumulative ammonia volatilization, pH value, and NH-N concentration in surface water. Six levels of reed () biochar amount, , 0%, 1%, 2%, 4%, 6% and 8% of soil weight of the 0-20 cm column, were applied in two typical paddy soils in sou-thern China, ., reddish clayey soil derived from quaternary red soil and granitic sandy soil derived from granite. Compound fertilizer was applied at a rate of 200 kg N·hm. The results showed that biochar application resulted in significant differences in the rate and cumulative amount of ammonia volatilization between the two soils and among different biochar treatments. For the granitic sandy soil, peak ammonia volatilization under different biochar treatments appeared at the second day after fertilization, which was decreased by 23.6%-53.4%. For the reddish clayey soil, peak ammonia volatilization appeared between the 7th to 13th day after fertilization, which increased with biochar addition level. The rate of ammonia volatilization from the granitic sandy soil was generally higher than that from the reddish clayey soil. For the granitic sandy soil, addition of <4% biochar could inhibit the ammonia volatilization and cumulative volatilization amount, with the greatest reduction (46.9%) at the treatment with 2% biochar addition. The addition of biochar did not affect the pH value of surface water at the early stage of rice growth. For the reddish clayey soil, the pH value and NH-N concentration in the surface water increased with biochar addition level, resulting in the increases of ammonia volatilization rate and cumulative volatilization amount by 1.3-10.5 times. Biochar addition level was the key factor affecting ammonia volatilization from the two soils. Elovich equation could well fit the variation trend of cumulative ammonia volatilization with time for the two soils, with the correlation reaching extremely significant level for each treatment. Overall, the application of reed biochar could suppress ammonia volatilization from the granitic sandy soil which was nearly neutral in acidity, while would promote ammonia volatilization via increasing pH value and NH-N concentration of surface water for the acidic reddish clayey soil. Therefore, appropriate dosages of reed biochar should be selected for different types of soil in order to reduce nitrogen loss.
稻草生物炭在洞庭湖区农田的应用可实现稻草的资源化利用并降低环境风险。2020年，进行了一项水稻盆栽试验，以研究不同生物炭施用量对氨挥发速率、累积氨挥发量、pH值和地表水NH-N浓度的影响。在中国南方两种典型稻田土壤中，施加了六级芦苇生物炭量，即占0-20厘米土层土壤重量的0%、1%、2%、4%、6%和8%。复合肥施用量为200 kg N·hm。结果表明，生物炭施用导致两种土壤以及不同生物炭处理之间氨挥发速率和累积量存在显著差异。对于花岗岩砂质土，不同生物炭处理下的氨挥发峰值出现在施肥后第二天，降低了23.6%-53.4%。对于第四纪红壤性黏土，氨挥发峰值出现在施肥后第7至13天，且随生物炭添加水平增加而增加。花岗岩砂质土的氨挥发速率总体高于第四纪红壤性黏土。对于花岗岩砂质土，添加<4%生物炭可抑制氨挥发和累积挥发量，在添加2%生物炭处理时降低幅度最大（46.9%）。生物炭添加在水稻生长前期对地表水pH值无影响。对于第四纪红壤性黏土，地表水pH值和NH-N浓度随生物炭添加水平增加而升高，导致氨挥发速率和累积挥发量增加1.3-10.5倍。生物炭添加水平是影响两种土壤氨挥发的关键因素。Elovich方程能很好地拟合两种土壤累积氨挥发量随时间的变化趋势，各处理相关性均达到极显著水平。总体而言，芦苇生物炭的施用可抑制酸性接近中性的花岗岩砂质土的氨挥发，而对于酸性的第四纪红壤性黏土，会通过提高地表水pH值和NH-N浓度促进氨挥发。因此，应针对不同类型土壤选择合适剂量的芦苇生物炭，以减少氮素损失。
