ABSTRACT

This study investigated the long-term (31 years) effects of mineral slag fertilizer (fused magnesium phosphate [FMgP] and calcium silicate [CaSi]) application on changes in the main soil chemical properties, including pH, electrical conductivity (EC), available phosphorus (P), soil organic carbon (SOC), and total nitrogen (TN) contents in paddy soils. Soil samples were obtained from six fertilizer treatments [(1) Nitrogen, phosphorus, and potassium chemical fertilizer only (CF); (2) CF + mineral slag fertilizer (CF+); (3) CF + rice straw (RS); (4) CF + rice straw + mineral slag fertilizer (RS+); (5) CF + rice straw compost (CM); and (6) NPK + rice straw compost + mineral slag fertilizer (CM+)] at five depth soils (0–5, 5–10, 10–15, 15–20, and 20–25 cm). An anaerobic incubation experiment was performed at 30°C to determine carbon (C) decomposition and nitrogen (N) mineralization potentials at every 2-week interval (0, 2, 4, 6, and 8 weeks). The results indicated that compared to non-mineral slag additions, both EC and available P increased by 36.6–136.6% in mineral slag addition treatments. Still, only compost addition mostly influenced pH values; meanwhile, SOC and TN exhibited an increase (~23.8%) in compost addition treatments but a reduction (~12.7%) in rice straw treatments by applying mineral slag fertilizer. Mineral slag addition reduced the C decomposition potential but enhanced N mineralization potential observed by the first-order reaction kinetic models. Our study suggested that mineral slag fertilizers affected the soil organic matter and its mineralization potentials.

摘要

本研究调查了矿渣肥料（熔融磷酸镁 [FMgP] 和硅酸钙 [CaSi]）对土壤主要化学性质变化的长期（31 年）影响，包括 pH、电导率 (EC)、可用水稻土中磷 (P)、土壤有机碳 (SOC) 和全氮 (TN) 含量。土壤样品来自六种肥料处理[(1) 仅施氮、磷和钾化肥 (CF)；(2)CF+矿渣肥(CF+)；(3)CF+稻草(RS)；（4）CF+稻草+矿渣肥（RS+）；(5)CF+稻草堆肥(CM)；(6) NPK + 稻草堆肥 + 矿渣肥 (CM+)] 在五种深度土壤（0-5、5-10、10-15、15-20 和 20-25 厘米）。在 30°C 下进行厌氧培养实验，以确定每 2 周间隔（0、2、4、6 和 8 周）的碳 (C) 分解和氮 (N) 矿化潜力。结果表明，与非矿渣添加相比，矿渣添加处理的EC和有效磷均增加了36.6-136.6%。尽管如此，只有堆肥添加主要影响 pH 值；同时，堆肥添加处理中 SOC 和 TN 显示出增加（~23.8%），但通过施用矿渣肥处理的稻草处理中显示出减少（~12.7%）。矿渣添加降低了 C 分解潜力，但提高了一级反应动力学模型观察到的 N 矿化潜力。我们的研究表明，矿渣肥料会影响土壤有机质及其矿化潜力。