Assessment of crop residue burning alternatives and their impact on soil health

Abstract:

Imagine a farmer standing at the edge of a harvested rice paddy, lighter in hand, about to set fire to five tonnes of straw because he has no affordable alternative. This scenario plays out across roughly 23 million hectares of rice land in China each autumn, releasing particulate matter and greenhouse gases while destroying organic carbon that took an entire season to build. This research compared five non-burning residue management options against open burning for their effects on Soil Organic Carbon (SOC), Microbial Biomass Carbon (MBC), aggregate stability, and air quality (PM2.5 emissions) over two rice-wheat cycles at the Yangtze Agricultural University, Wuhan, Hubei, during 2021-2023. Biochar conversion raised SOC by 0.34 percentage points and MBC by 120% over burning, while reducing PM2.5 emissions by 94%. Composting ranked second for SOC gain (+0.27 points). Incorporation and mulching offered moderate benefits. The Happy Seeder, which sows directly into standing stubble, improved SOC by 0.16 points and virtually eliminated field emissions. These findings offer quantified evidence that affordable alternatives to burning exist and can rebuild soil health within two years.