Excessive applications of chemical fertilizers (e.g., nitrogen fertilizers) result in soil degradation, while organic manure application can alleviate soil degradation and rebuild a healthy soil. However, the effect of organic manure application on alleviating soil degradation over long-term fertilization remains poorly understood. Using soils (Ferralic Cambisol) that had been collected from a long-term fertilization experiment for 23 years (1990 − 2013) in subtropic South China, we showed that soil organic carbon (SOC) stocks increased by 2.5 times following 23 years of manure fertilizations (pig manure or a combination of manure and chemical fertilizers) or by 1.4 − 1.8 times following non-manure fertilizations, compared to the initial SOC stock in 1990. Strikingly, soil bulk density after 23 years fertilizations decreased in the order: 1.41 g cm⁻³ (manure) > 1.26 g cm⁻³ (no fertilizer) > 1.12 g cm⁻³ (chemical fertilizer), suggesting that long-term manure fertilization increased soil bulk density when compared to the non-manure treatments. The X-ray micro-computed tomography further demonstrated that compared to the non-manure treatments, manure fertilizations decreased the number of pores, throats and paths as well as porosity. In addition, the stock of oxalate-extractable Al and Fe increased by 2 times following 23 years of manure fertilizations, relative to the initial soil. In summary, this study for the first time showed that changes in mineral reactivity impact soil physical properties and the potential of soils to stabilize C, strengthening the possibility in alleviating soil degradation and rebuilding a healthy soil.

化肥（如氮肥）的过量施用会导致土壤退化，而有机肥的施用会减轻土壤退化并重建健康的土壤。但是，对于长期施肥，施用有机肥料减轻土壤退化的效果仍然知之甚少。使用从华南亚热带地区进行了23年（1990年至2013年）的长期施肥实验收集的土壤（草甘膦），我们显示了23年的肥料施肥后，土壤有机碳（SOC）储量增加了2.5倍（猪粪或粪肥和化肥的组合），或与1990年的初始SOC相比，非粪肥施肥后降低了1.4 − 1.8倍。引人注目的是，施肥23年后的土壤容重依次降低：1.41 g cm⁻³（肥料）> 1.26 g cm ^-3（无肥料）> 1.12 g cm ^-3（化学肥料），表明与非肥料处理相比，长期施用肥料会增加土壤容重。X射线计算机断层摄影进一步证明，与非肥料处理相比，肥料施肥减少了孔，喉咙和路径的数量以及孔隙率。此外，相对于最初的土壤，在施用了23年的肥料后，草酸盐可萃取的Al和Fe的存量增加了2倍。总而言之，这项研究首次表明矿物质反应性的变化会影响土壤的物理性质以及土壤稳定碳的潜力，从而增强了缓解土壤退化和重建健康土壤的可能性。