Globally, poorly managed pasture can contribute to increasing greenhouse gas (GHG) emissions. In Brazil, sustainable management systems are being proposed to reduce carbon dioxide (CO₂) emissions and increase the soil C stock under degraded pasture. However, despite the potential benefits in the adoption of sustainable management systems, few studies have been carried out seeking to analyze their long-term effects on the soil C cycle. In this study, we used the DayCent model to simulate the effects of converting poorly managed pastures (PMP) to more-intensive and diversified systems of pasture management [fertilized pasture (FP), integrated crop-livestock (ICL) and integrated livestock-forest (ILF)] on long‐term soil C stocks and microbial biomass C (MBC). We also evaluated the effects of different pasture management scenarios for FP (fertilization frequency), ICL (time of implementation of the crop phase) and IFL (spacing between the tree rows). The DayCent model estimated that the conversion of PMP to FP, ICL and ILF increases the soil C stocks by 0.95, 0.04–0.70 and 0.16 Mg ha⁻¹ yr⁻¹, respectively. Similarly, the MBC contents also increased with conversion, mainly for ICL and ILF. In addition, the fertilization of the pasture every year (FP), the implementation of the crop phase within two years (ICL) and the spacing between the tree rows of 15 m (ILF) showed the highest soil C stocks and MBC contents. FP, ICL and IFL were also GHG sinks of 43, 57 and 116 Mg CO₂eq ha⁻¹, respectively. These results can help national initiatives associated with the recovery of degraded pasture in Brazil.

在全球范围内，牧场管理不善可能导致温室气体（GHG）排放增加。在巴西，正在提议采用可持续管理系统来减少二氧化碳（CO ₂）排放并增加退化草场下的土壤碳储量。然而，尽管采用可持续管理系统具有潜在的好处，但很少进行研究来分析其对土壤碳循环的长期影响。在这项研究中，我们使用DayCent模型来模拟将管理不善的牧场（PMP）转换为更密集和多样化的牧场管理系统[施肥牧场（FP），农作物-畜牧业（ICL）和畜牧-森林一体化]的效果（ILF）]上的长期土壤碳储量和微生物生物量碳（MBC）。我们还评估了不同牧场管理方案对FP（施肥频率），ICL（作物阶段的实施时间）和IFL（树行间距）的影响。DayCent模型估计PMP向FP的转化，^-1 yr ^-1。同样，MBC内容也随转换而增加，主要是针对ICL和ILF。此外，每年的牧草施肥（FP），两年内的作物种植阶段（ICL）以及15 m的树行间距（ILF）显示最高的土壤C储量和MBC含量。FP，ICL和IFL分别也是43、57和116 Mg CO ₂ eq ha ^-1的温室气体汇。这些结果可有助于与巴西退化牧场的恢复有关的国家计划。