Abstract

Biochar as an eco-friendly substance, depending on its origin and production conditions, may have significant effects on soil properties, nutrient availability and K dynamics of arid and semi-arid soils. Biochars produced from wheat and corn residues, pyrolyzed at 250, 450 and 650 °C during 2, 4 and 8 h, were applied to four representative calcareous soils. First, 2 g of each biochar was added to 100 g of each soil and incubated under field capacity for 90 days. Then the soil samples were analyzed for soil properties, nutrient availability and K fractions. All biochars increased soil CEC, ECe and available K, P, Fe, Zn, Mn and Cu. The biochars produced at higher temperature had larger effect on soil properties, P and K availability, and smaller effect on Fe, Mn and Zn availability. The used biochars increased the amounts of soluble, exchangeable, non-exchangeable and HNO₃-extractable K to 143–348, 316–605, 597–1,064 and 1,056–2,012 mg kg⁻¹, respectively. The wheat biochar had larger effect on soil K than the corn biochar. Potassium saturation percentage increased with biochar application due to the larger effect of biochar on exchangeable K than CEC. The biochars increased the percentage of soluble K due to the limited capacity of exchange sites and clay interlayers for K adsorption. Biochar had different effect on the experimental soils; and the content of soluble K in the coarse-textured soils after biochar application increased more, than other K fractions. It was concluded that biochars, particularly the wheat biochar produced at higher temperature, have potential for improving K management of K depleted soils.

摘要

生物炭作为一种环保物质，取决于其来源和生产条件，可能对干旱和半干旱土壤的土壤性质、养分有效性和钾动态产生重大影响。将小麦和玉米残留物生产的生物炭在 2、4 和 8 小时内在 250、450 和 650°C 下热解，应用于四种代表性的钙质土壤。首先，将 2 g 每种 biochar 添加到 100 g 每种土壤中，并在田间容量下孵育 90 天。然后分析土壤样品的土壤特性、养分有效性和钾含量。所有生物炭都增加了土壤 CEC、ECe 和速效 K、P、Fe、Zn、Mn 和 Cu。在较高温度下产生的生物炭对土壤性质、P和K有效性的影响较大，对Fe、Mn和Zn有效性的影响较小。使用的生物炭增加了可溶性、可交换性、₃ -可萃取 K 分别为 143–348、316–605、597–1,064 和 1,056–2,012 mg kg ^-1。小麦生物炭对土壤钾的影响大于玉米生物炭。由于生物炭对可交换钾的影响大于 CEC，钾饱和百分比随着生物炭的应用而增加。由于交换位点和粘土夹层对 K 吸附的能力有限，生物炭增加了可溶性 K 的百分比。生物炭对试验土壤有不同的影响；生物质炭施用后粗质地土壤中可溶性钾含量较其他钾含量增加更多。得出的结论是，生物炭，特别是在较高温度下生产的小麦生物炭，具有改善贫钾土壤钾管理的潜力。