ABSTRACT

Biochar production from organic waste offers an important alternative for waste management, also improves soil properties (bio-physico-chemical) and reduces heavy metal pollution risk caused by the excessive use of chemical fertilizers applied directly to the soils. Biochar is also proposed as an important management strategy to mitigate the negative impacts of greenhouse gases, which are among the most important causes of global climate change. This study aimed to investigate the effects of biochars produced from six different plant wastes on soil enzyme activity, CO₂–C emission, total nitrogen (Nt), and nitrate (NO₃–N) concentrations. Almond shell (AS), tobacco waste (TW), pomegranate peel (PP), cotton waste (CW), orange peel (OP), and wheat straw (WS) biochars were applied to the soil at the rates of 0.5, 1.0, and 1.5%, and the biochar amended soils were incubated in the laboratory environment (25 ± 2) for 37 weeks. The highest CO₂ ̶ C emission was recorded in OP biochar treatment, while the lowest emission was measured in PP treatment, indicating that OP biochar addition tended to decrease C mineralization in the soil. The addition of AS biochar significantly increased the dehydrogenase and urease enzyme activities, while urease activity did not show a significant increase. The results can be attributed to the differences in composition and properties (C: N ratio, pH) of the biochars applied as well as the nature of the feedstocks used in biochar production. Biochar applications increased the Nt and NO₃–N concentrations of the soils, and the highest increase was obtained in the WS treatment. The results of the study revealed that PP biochar can be recommended to reduce CO₂–C emission from soils, AS biochar has a significant effect on urease and dehydrogenase enzyme activities, and the effect of WS biochar on Nt and NO₃–N concentrations of soils were higher than the other five biochar types.

摘要

从有机废物中生产生物炭为废物管理提供了一种重要的替代方案，还可以改善土壤特性（生物物理化学）并降低因过度使用直接施用于土壤的化肥而造成的重金属污染风险。生物炭也被提议作为减轻温室气体负面影响的重要管理策略，温室气体是全球气候变化的最重要原因之一。本研究旨在研究由六种不同植物废物产生的生物炭对土壤酶活性、CO ₂ –C 排放、总氮 (Nt) 和硝酸盐 (NO ₃–N) 浓度。将杏仁壳（AS）、烟草废料（TW）、石榴皮（PP）、棉花废料（CW）、橙皮（OP）和麦秆（WS）生物炭以0.5、1.0、和 1.5%，生物炭改良土壤在实验室环境（25±2）中培养 37 周。最高的 CO ₂̶ C 排放记录在 OP 生物炭处理中，而最低排放量在 PP 处理中测量，表明添加 OP 生物炭倾向于减少土壤中的 C 矿化。AS生物炭的加入显着提高了脱氢酶和脲酶活性，而脲酶活性没有显着增加。结果可归因于所应用的生物炭的组成和性质（C:N 比、pH）的差异以及用于生物炭生产的原料的性质。生物炭的应用增加了土壤的 Nt 和 NO ₃ -N 浓度，WS 处理获得了最大的增加。研究结果表明，PP biochar 可推荐用于减少 CO ₂土壤-C排放，AS生物炭对尿素酶和脱氢酶活性有显着影响，WS生物炭对土壤Nt和NO ₃ -N浓度的影响高于其他5种生物炭类型。