Purpose

Biochars have potential to reduce soil acidity and Al³⁺ toxicity, and increase the availability of soil nutrients. This study aimed to compare the effectiveness of biochars and their raw feedstocks in amelioration of soil acidity.

Materials and methods

Ten ameliorants comprising of five biochars (pyrolyzed at 550°C) and their corresponding feedstocks (wheat chaff, canola stubble, vetch hay, lucerne pellets, and poultry litter) were added (1% of soil weight) to sandy Tenosol and loamy Chromosol with both having similar Al³⁺ concentrations but Chromosol having nine times greater pH buffer capacity. The soils with the ameliorants were incubated for 7 weeks (incubation phase), before being planted with an Al-sensitive wheat (ES8) for 18 days (plant phase).

Results and discussion

Biochars outperformed their feedstocks in increasing soil pH, leading to a significant reduction of Al³⁺ toxicity. Biochar additions increased shoot growth by 137‒341% for Tenosol and 10‒295% for Chromosol, whereas their feedstocks increased shoot growth by 25‒233% for Tenosol and -38‒136% for Chromosol. Poultry-litter biochar increased soil pH greater than the corresponding poultry-litter treatments by 1.59 units in the Tenosol and 0.79 units in the Chromosol at the end of the plant phase. In addition, all organic amendments (except wheat-chaff and its biochar) significantly increased shoot P concentrations with poultry-litter biochar achieving the highest Olsen P and shoot P concentrations in both soils. Evidently, high alkalinity and nutrient contents of poultry-litter biochar resulted in the greatest increases in soil pH and shoot biomass in both soils.

Conclusions

Biochars were more effective at ameliorating soil acidity than their corresponding feedstocks primarily via increasing soil pH and supplying plant nutrients, depending on soil type. Poultry-litter biochar was the most effective on both soils.

中文翻译：

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生物炭及其原料在改善铝敏感小麦生长的酸性土壤方面的短期效果不同

目的

生物炭有可能降低土壤酸度和 Al ³⁺毒性，并增加土壤养分的可用性。本研究旨在比较生物炭及其原料在改善土壤酸度方面的有效性。

材料和方法

将包含五种生物炭（在 550°C 下热解）及其相应原料（小麦糠、油菜残茬、野豌豆干草、苜蓿颗粒和家禽垫料）的 10 种改良剂（土壤重量的 1%）添加到含两者都具有相似的 Al ³⁺浓度，但 Chromosol 具有 9 倍的 pH 缓冲容量。将含有改良剂的土壤培养 7 周（培养阶段），然后种植铝敏感小麦 (ES8) 18 天（植物阶段）。

结果和讨论

生物炭在提高土壤 pH 值方面的表现优于其原料，导致 Al ³⁺显着减少毒性。添加生物炭使 Tenosol 的枝条生长增加了 137–341%，Chromosol 增加了 10–295%，而它们的原料使 Tenosol 的枝条生长增加了 25–233%，Chromosol 增加了 -38–136%。在植物阶段结束时，家禽垫料生物炭使土壤 pH 值比相应的家禽垫料处理增加了 1.59 单位的 Tenosol 和 0.79 单位的 Chromosol。此外，所有有机改良剂（小麦糠及其生物炭除外）显着增加了地上部磷浓度，家禽垫料生物炭在两种土壤中都达到了最高的奥尔森磷和地上部磷浓度。显然，家禽垫料生物炭的高碱度和营养成分导致两种土壤中土壤 pH 值和芽生物量的最大增加。

结论

生物炭在改善土壤酸度方面比其相应的原料更有效，主要是通过提高土壤 pH 值和提供植物养分，这取决于土壤类型。家禽垫料生物炭对两种土壤的效果都最好。