Modified (metal oxide) biochar is widely used for the remediation of degraded soils, but there has been limited research work on its effect on phosphorus (P) fractionation and biochemical properties under different soil conditions.

In a study published in Environmental Sciences Europe, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences and their collaborators revealed that magnesium-modified wheat straw biochar (Mg-WBC) significantly improves P availability and soil health in different soil types, providing a promising strategy for soil remediationa and sustainable agriculture.

Researchers measured the impact of unmodified WBC and Mg-WBC on phosphorus fractionation and biochemical properties in Qiyang and Harbin soils. They set up control and four different dose treatment groups, and evaluated the impact of biochar by determining soil chemical properties, enzyme activities, and microbial biomass.

The results showed that both WBC and Mg-WBC significantly improved soil characteristics. Biochar addition had a positive effect on the improvement of acidic soils. Mg-WBC significantly improved the P availability in both soils by increasing the moderately labile P content, while decreasing the non-labile P content.

The findings suggest that Mg-WBC application enhances phosphorus cycling, increases nutrient availability (especially labile P and carbon), and aids in remediating acidic soils. This study promotes both agronomic productivity (higher yields) and environmental sustainability by recycling agricultural waste (wheat straw) and reducing nutrient loss.

"Magnesium-modified biochar is a powerful tool for improving soil fertility, particularly P availability in its most plant-usable forms," said Khan Muhammad Numan from XTBG. "Our findings recommend that appropriate biochar application strategy should be selected according to different soil conditions for the best soil improvement effects."