麻豆淫院

Farming produces a huge amount of crop waste, including straw, husks, and stalks every growing season. Unfortunately, common disposal methods鈥攂urning, plowing the waste back into the fields, using it as animal feed, and even composting鈥攔elease greenhouse gases (GHG) such as methane (CH₄), nitrous oxide (N₂O), and carbon dioxide (CO₂), contributing to climate change and long-term risks to food security.

In contrast, biochar鈥攁 charcoal-like material made by heating agricultural waste in low-oxygen conditions (pyrolysis)鈥攐ffers a promising and eco-friendly alternative, according to a new study by Chinese scientists.

The team, led by Profs. Yan Xiaoyuan and Xia Longlong from the Institute of Soil Science of the Chinese Academy of Sciences, showed that biochar can deliver lasting benefits for food security and climate mitigation when applied to farmland over the long term. In particular, the study showed that repeated annual applications not only sustain but also amplify biochar's positive effects on crop yield, soil health, and GHG reduction.

In this study, the researchers analyzed high-quality field experiment records from 438 studies, including consecutive annual data from 29 long-term field experiments. The results, published in , demonstrate that annual biochar application over four years or more increased global crop yields by an average of 10.8%, cut CH₄ emissions by 13.5% and N₂O emissions by 21.4%, and raised soil organic carbon (SOC) content by 52.5%.

While single application of biochar showed weakened effects over time due to the aging effect, the study showed it was still beneficial, with continued yields and SOC rise, and continued CH₄ and N₂O mitigation, though with a weakening trend.

"We wondered how significant biochar's potential could be for carbon sequestration and emission reduction in global farmlands under long-term application," said YANG Jingrui, first author of the study and a Ph.D. student from ISSCAS.

Based on current straw and biochar management practices, the researchers estimated that converting 70% of straw into biochar for agricultural fields could boost global grain yields by 190 million tons annually and enhance carbon dioxide removal (CDR) potential by 2.01 Pg of CO₂-eq annually鈥攁bout 30% of China's average annual grain yield from 2018 to 2021.

After accounting for GHG emissions from biochar production (0.25 tons of CO₂ per ton of biochar), the net CDR potential was still 1.84 Pg of CO₂-eq per year, offsetting about 4.6% of global fossil fuel CO₂ emissions.

The findings suggest that strategic deployment of biochar at multi-year intervals or with break periods between yearly applications could maintain its benefits cost-effectively while minimizing risks. Expanding field experiments and comparative trials across different soil types, climates, and cropping systems are crucial for refining application strategies, especially in determining optimal frequencies and rates.

While periodic biochar application tailored to local conditions can reduce costs and secure long-term advantages, the initial economic burden may deter risk-averse farmers.

"Since farmers are unlikely to increase input costs unless there is strong evidence it pays off, large-scale demonstration trials in major grain-producing regions such as the North China Plain and the U.S. Corn Belt are essential to prove both economic and environmental benefits," said Prof. Yan.

A cost-benefit analysis conducted by the team showed that increased yields and reduced GHG emissions could compensate for around 81% of biochar procurement costs, with greater gains possible when nitrogen loss reduction is factored in. The researchers argue that government-backed subsidies and supportive policies will be crucial to scaling biochar adoption and realizing its global potential for sustainable agriculture and climate mitigation.