In a recent study published in the Journal of Agriculture and Food Research, Chao Huang, Haiqing Chen, Xuchen Liu, and their colleagues investigated the profound impacts of 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 application and different tillage methods on soil health in wheat-maize rotation systems. Their findings offer crucial insights into mitigating nitrous oxide (N₂O) emissions, enhancing soil aggregate stability, and boosting nutrient content, all vital for sustainable agricultural productivity on the North China Plain.

Long-term reliance on single tillage methods can degrade soil texture and reduce organic matter, threatening agricultural output. The North China Plain, a cornerstone of China’s food security, has experienced such deterioration, including subsoil compaction and plow pan formation, which hinder soil aeration and promote N₂O emissions. This study aimed to identify optimal strategies by combining subsoiling (ST) and conventional rotary tillage (RT) with varying biochar application rates: 0 t/hm² (B0), 4.5 t/hm² (B1), and 9.0 t/hm² (B2).

The results demonstrated biochar’s significant role in environmental mitigation. Biochar application reduced N₂O emissions by an impressive 19.6%-29.5% over the entire wheat-maize rotation period. Compared to traditional rotary tillage without biochar (RTB0), the 4.5 t/hm² biochar treatment (RTB1) decreased N₂O emissions by 39.1% during the winter wheat season and 25.7% during the summer maize season. Similarly, under subsoiling, N₂O emissions were reduced by 35.8% (STB1) and 34.0% (STB2) during the winter wheat season. This reduction is likely due to biochar’s ability to adsorb N₂O precursors like ammonium and nitrate, and its direct N₂O capture capabilities, alongside its potential to inhibit denitrification by increasing soil 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.

Beyond greenhouse gas reduction, biochar also played a pivotal role in improving soil physicochemical properties and nutrient content. Soil organic matter (SOM), a key indicator of soil health, significantly increased in the top 20 cm with biochar application, with subsoiling enhancing these effects. The highest increases in SOM (15.5%), 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) (17.1%), and microbial biomass nitrogen (MBN) (17.1%) were observed in the STB2 treatment (subsoiling with 9.0 t/hm² biochar). Biochar also increased soil pH and reduced bulk density, with more pronounced effects at higher application rates. Subsoiling, in particular, proved more effective in enhancing SOM under the wheat-maize rotation system compared to rotary tillage.

While biochar did not significantly affect the stability of non-water-stable aggregates, it substantially increased the proportion of aggregates larger than 5 mm and improved overall aggregate stability parameters like mean weight diameter (MWD) and geometric mean diameter (GMD) in the surface soil after the second crop. This improvement in aggregate stability is crucial for reducing soil erodibility and enhancing soil fertility. The positive effects on aggregate stability were particularly evident with the 4.5 t/hm² biochar application under subsoiling.

A comprehensive evaluation using the TOPSIS model indicated that subsoiling combined with 4.5 t/hm² biochar (STB1) demonstrated a more favorable overall improvement in soil quality and aggregate stability compared to higher biochar rates or rotary tillage. This optimal combination effectively enhanced soil nutrients and structure while simultaneously reducing greenhouse gas emissions.

In conclusion, this study provides compelling evidence that the strategic integration of subsoiling with a moderate biochar application rate of 4.5 t/hm² offers a sustainable and effective solution for improving soil health and mitigating climate change in wheat-maize rotation systems. These long-term benefits underscore the importance of such agricultural practices for ensuring food security and environmental sustainability.

Source: Huang, C., Chen, H., Liu, X., Ma, S., Li, Y., Zhang, Z., Tang, H., Wang, X., & Liu, Z. (2025). Effects of biochar on soil N₂O emissions, aggregate stability and nutrients under subsoiling and rotary tillage in wheat-maize rotation systems. Journal of Agriculture and Food Research.