Agrosilvopastoral systems have been promoted as sustainable models that combine crops, livestock grazing, and forestry in the same area. We hypothesize that agrosilvopastoral systems can improve soil C and N stocks over time. Therefore, in this study, we aimed to evaluate the changes in soil C and N stocks after conversion of low-productivity pasture into well-managed pasture and agrosilvopastoral land in the Brazilian Cerrado. Soil samples were collected in 2016 and 2018 at 0–5, 5–10, 10–20, and 20–30 cm depths from the following areas: integrated crop-livestock-forest (ICLF), marandu grass (Brachiaria brizantha) monoculture (MAR), low productivity pasture of signal grass (Brachiaria decumbens) monoculture (PAST), and native vegetation (NV; “Cerrado”). The C and N content and stocks, ¹³C natural abundance, and C contents in the physical and chemical fractions of soil organic matter (SOM) were measured. The ICLF and MAR systems promoted faster recovery of soil C and N stocks at all soil depths compared with PAST. The C content of the free light fraction of SOM under the ICLF and MAR systems increased, reaching values similar to NV up to 20 cm. The C content was higher in the humin fraction at all depths in all areas, and for this measurement, the ICLF system performed remarkably compared with PAST at a depth of 5−10 cm. Our findings support the hypothesis that conversion of low-productivity pasture into agrosilvopastoral and actively managed pasture systems leads to improvements in soil quality and C and N stocks in the Brazilian Cerrado.

农业农牧业系统已被推广为在同一地区将农作物，牲畜放牧和林业结合起来的可持续模式。我们假设农业农牧系统可以随着时间的推移改善土壤的碳和氮储量。因此，在这项研究中，我们旨在评估巴西Cerrado地区将低生产力的牧场转变为管理良好的牧场和农林牧草土地后土壤C和N储量的变化。在2016年和2018年从以下地区分别以0-5、5-10、10-20和20-30厘米的深度采集了土壤样品：作物-牲畜-森林（ICLF），马兰杜草（Brachiaria brizantha）单种（ MAR），信号草（Brachiaria decumbens）的低生产力牧场单一栽培（PAST）和原生植被（NV；“ Cerrado”）。碳，氮含量及库存量¹³测量了土壤中C的自然丰度，以及土壤有机质（SOM）的理化分数中的C含量。与PAST相比，ICLF和MAR系统促进了在所有土壤深度下土壤C和N储量的更快恢复。在ICLF和MAR系统下，SOM的自由光部分的C含量增加，达到20厘米时类似于NV的值。在所有区域的所有深度的腐殖质含量中，C含量均较高，并且在此测量中，与5-10 cm深度的PAST相比，ICLF系统的性能显着提高。我们的发现支持以下假设：低生产力的牧场转变为农林牧区和积极管理的牧场系统会改善巴西塞拉多的土壤质量以及碳和氮储量。