ABSTRACT

Biochar due to its high K content may affect K forms and dynamics. The effect of biochars produced from licorice root pulp, municipal waste and cow manure at 300 °C and 600 °C on K forms, release and fixation in a loamy calcareous soil was investigated. The soil samples were analyzed after biochar application and incubation at field water-holding capacity or saturation conditions. The cow manure and municipal waste biochars increased all K forms, while licorice root pulp biochar only increased exchangeable K (10%). Cumulative K released to 0.01 M CaCl₂ for the control soil was 101 mg kg⁻¹, increasing to 108, 182 and 418 mg kg⁻¹, with the application of licorice root pulp, municipal waste and cow manure biochars produced at 300 °C, and increased to 112, 200 and 486 mg kg⁻¹ with the application of the biochars produced at 600 °C, respectively. Generally, 0.025 M CaCl₂ extracted more K than 0.01 M CaCl₂ (means of 250 vs. 230 mg kg⁻¹). Saturation had a smaller effect on K forms and dynamics; increasing non-exchangeable K. Biochar increased soil K fixation. Biochar depending on its origin and pyrolysis conditions may be used as an amendment for increasing K supplying power of calcareous soils.

摘要

Biochar 由于其高 K 含量可能会影响 K 的形式和动态。研究了在 300 °C 和 600 °C 下由甘草根浆、城市垃圾和牛粪生产的生物炭对肥沃钙质土壤中钾的形成、释放和固定的影响。在施用生物炭并在田间持水能力或饱和条件下孵育后对土壤样品进行分析。牛粪和城市垃圾生物炭增加了所有形式的钾，而甘草根浆生物炭仅增加了交换性钾（10%）。对照土壤释放到 0.01 M CaCl _{2的累积 K 为 101 mg kg} ^-1，增加到 108、182 和 418 mg kg ^-1，随着甘草根浆、城市垃圾和牛粪生物炭的应用，在 300 °C 下生产的生物炭，在 600 °C 下生产的生物炭分别增加到 112、200和 486 mg kg ^{-1 。}通常，0.025 M CaCl ₂提取的 K 比 0.01 M CaCl ₂多（平均值为 250 对 230 mg kg ^-1）。饱和度对 K 形式和动态的影响较小；增加非交换钾。 Biochar 增加土壤固钾。根据其来源和热解条件，生物炭可用作增加钙质土壤供钾能力的改良剂。