ABSTRACT A profound consideration of soil organic carbon (SOC) and SOC pools as affected by the long-term use of fertilizer in a fixed crop sequence is essential to understand and maintain the health and productivity of soil. The dynamics of SOC pools, i.e. total soil organic carbon (TOC) and its different fractions under a rice-wheat cropping system subjected to various fertilizer management strategies over 42 years was investigated near Uttarakhand, India. The soil at the experimental site was an Aquic Hapludoll consisting of a poorly drained silty clay loam (1–1.5 m deep) overlying loamy to sandy sediments. Over 42 years, application of 100% NPK+ FYM (Farm Yard Manure) was the most effective management system in increasing organic C up to 0 to 60 cm soil depths under rice-wheat sequence. The combination of this integrated input application (100% NPK + 15 t ha−1 FYM) significantly built organic carbon fractions like total organic carbon, microbial biomass C (MBC), particulate organic C (POC), KMnO4 oxidizable C, Humic C, Fulvic C, Humin C, water-soluble carbon and hot water extractable carbohydrates at all four soil depths. Hence, application of FYM along with NPK resulted in a significant positive building up of all pools in the treatment at all four depths. Therefore, balance fertilization is panaceally important for sustaining improved soil health with balanced organic status and production potentiality of the soil for rice-wheat cropping sequence.

中文翻译：

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印度北部软土中稻麦序列长期施肥试验下不同库土壤有机碳的垂直分布

摘要 土壤有机碳 (SOC) 和 SOC 库受固定作物序列中长期使用肥料的影响，对于了解和维持土壤的健康和生产力至关重要。在印度北阿坎德邦附近调查了 42 年来在采用各种肥料管理策略的稻麦种植系统下 SOC 库的动态，即总土壤有机碳 (TOC) 及其不同部分。实验地点的土壤是 Aquic Hapldoll，由排水不良的粉质粘壤土（1-1.5 m 深）覆盖在壤土到沙质沉积物上。42 年来，施用 100% NPK + FYM（农家肥）是在稻麦序列下将有机碳增加到 0 至 60 厘米土壤深度的最有效管理系统。这种集成输入应用（100% NPK + 15 t ha − 1 FYM）的组合显着构建了有机碳部分，如总有机碳、微生物生物量 C (MBC)、颗粒有机 C (POC)、KMnO4 可氧化 C、腐殖质 C、在所有四个土壤深度中的 Fulvic C、Humin C、水溶性碳和热水可提取碳水化合物。因此，FYM 与 NPK 的应用导致处理中所有四个深度的所有池的显着正累积。因此，平衡施肥对于维持改善的土壤健康具有平衡的有机状态和水稻 - 小麦种植顺序的土壤生产潜力至关重要。Fulvic C、Humin C、水溶性碳和热水可提取碳水化合物在所有四个土壤深度。因此，FYM 与 NPK 的应用导致处理中所有四个深度的所有池的显着正累积。因此，平衡施肥对于维持改善的土壤健康、平衡有机状态和稻麦种植土壤的生产潜力至关重要。在所有四个土壤深度中的 Fulvic C、Humin C、水溶性碳和热水可提取碳水化合物。因此，FYM 与 NPK 的应用导致处理中所有四个深度的所有池的显着正累积。因此，平衡施肥对于维持改善的土壤健康、平衡有机状态和稻麦种植土壤的生产潜力至关重要。