Biochar (BC) and polymers are cost-effective additives for soil quality improvement and long-term sustainability. The additional use of the oyster shells (OS) powder in BC- or polymer-treated soils is recommended as a nutrient source, to enhance aggregation and to increase enzyme activities. The effects of soil treatments (i.e., BC (5 Mg ha⁻¹) and polymers (biopolymer at 0.4 Mg ha⁻¹ or polyacrylamide at 0.4 Mg ha⁻¹) with or without the OS (1%)) on the short-term changes were evaluated based on a 30-day incubation experiment with respect to several variables (e.g., CO₂ release, NH₄⁺ and NO₃⁻ concentrations, aggregate-size classes, and enzyme activities in an agricultural Luvisol). The BC and BP with the addition of OS increased the portion of microaggregates (<0.25 mm) relative to the control soil without any additions, while PAM alone increased the portion of large macroaggregates (1–2 mm). Concentrations of NO₃⁻ also increased in soils treated with OS, OS + BC, and OS + BP as result of the increased chitinase and leucine aminopeptidase activities. The BC and BP when treated with the additional OS had significant short-term impacts on N mineralization without affecting C mineralization in soil. Consequently, the combination of BC or BP with OS was seen to accelerate N turnover without affecting C turnover (and related C losses) from soil. As such, the addition of these additives contributed considerably to the improvement of soil fertility and C sequestration.

生物炭（BC）和聚合物是提高土壤质量和长期可持续性的高性价比添加剂。建议在BC或聚合物处理过的土壤中额外使用牡蛎壳（OS）粉末作为营养源，以增强聚集作用并增加酶活性。所述的土壤处理（即，BC（5镁公顷效果^-1）和聚合物（生物聚合物在0.4镁公顷^-1的聚丙烯酰胺在0.4镁公顷或^-1）具有或不具有OS（1％））的短期基于30天培养实验相对于几个变量（变动进行评价例如，CO ₂的释放，NH ₄ ⁺和NO ₃ ^-农业Luvisol中的浓度，骨料大小分类和酶活性）。相对于不添加任何添加剂的对照土壤，添加OS的BC和BP增加了微骨料的比例（<0.25 mm），而单独使用PAM则增加了大型大骨料的比例（1-2 mm）。NO浓度₃ ^-由于几丁质酶和亮氨酸氨基肽酶活性的增加，在用OS，OS + BC和OS + BP处理过的土壤中也有增加。当使用额外的OS处理时，BC和BP对N矿化具有显着的短期影响，而不会影响土壤中的C矿化。因此，将BC或BP与OS结合使用可加速氮素的转化，而不会影响土壤中的C转化率（及相关的C损失）。这样，这些添加剂的添加极大地改善了土壤肥力和固碳。