Wang, et al (2024) Comparative Effects of Straw and BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More on N₂O Emissions from Acidic Soils. Journal of Soil Science and Plant Nutrition. https://doi.org/10.1007/s42729-024-01742-9

Biochar amendment is a potential strategy to mitigate soil acidification and nitrous oxide (N2O) emissions. However, its effectiveness on N2O emissions from acidic soils, particularly in tea fields, remains uncertain. This study compares the effects of straw and biochar on N2O emissions from acidic soils in tea fields with different cultivation periods in South Central China.

A 48-day microcosm experiment was conducted using soils from tea fields cultivated for 5 years (pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More 5.8, slightly acidic) and 15 years (pH 4.5, acidic). The experiment examined N2O emissions in response to amendments with straw and biochar.

The results showed that biochar addition alone significantly increased soil pH by 1.14 units in 5-year soils and by 0.54 units in 15-year soils, leading to reductions in N2O emissions by 28.46% and 68.34%, respectively. In contrast, straw addition alone increased cumulative N2O emissions by 141.97% in 5-year soils and by 127.45% in 15-year soils. However, the combined application of straw and biochar significantly reduced N2O emissions compared to straw alone in both soil types. Notably, N2O emissions from the more acidic soil (15-year cultivation) were 7.12 times higher than those from the slightly acidic soil (5-year cultivation) under control conditions.

Correlation analysis indicated that N2O emissions were positively correlated with dissolved organic carbon (DOC), microbial biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More carbon (MBC), and ammonium nitrogen (NH4+-N), but negatively correlated with pH.

These findings suggest that biochar, compared to straw, can effectively increase soil pH and mitigate N2O emissions from acidic soils, making it a promising strategy for reducing soil N2O emissions and alleviating soil acidification.