The decay constant (k) of soil organic carbon can be used in the decision making of soil management practices and it is an indicative of the spatial variability of soil carbon stability, which depends on the interactions of physical, chemical and biological factors within agroecossystem. The aim of this work was to determine the spatial variability structure of soil carbon losses, expressed by the factor k, and its relationship with the soil attributes in sugarcane crops, in the central-south region of Brazil. The experiments were carried out in areas of commercial sugarcane plantations, in the cities of Motuca (MOT), Guariba (GUA) and Pradópolis - SP (PAD), in the State of São Paulo, and Aparecida do Taboado (APT), in Mato Grosso do Sul. The measurements of soil CO₂ emission (FCO2) were recorded in the areas of study by the LI-COR system (LI-8100). The multivariate approach indicated that the two principal components (PC1 and PC2) explained around 55% to 68% of the total variability contained in the dataset in the areas studied, respectively. The soil physical attributes showed discriminatory power within PC1 and indicated a contrast between air-filled pore space and soil water content. In PC2, the chemical attributes indicated a joint action of the cations exchange capacity and available phosphorous content. PAD and APT areas presented negative and significant spatial patterns between factor k and PC1. For the spatial patterns between k and PC2 in GUA and APT, values with negative and significant correlations occurred. The results indicate that the soil carbon accumulation potential presented high spatial variability on a small scale; thus, in the same area, there were changes in the spatial patterns of factor k, presenting regions with potential accumulations or sources of carbon in the system of cultivation of raw cane, being able to be carried out the specific management in the same productive area.

土壤有机碳的衰减常数（k）可用于土壤管理实践的决策，它表示土壤碳稳定性的空间变异性，它取决于农业生态系统内物理，化学和生物因素之间的相互作用。这项工作的目的是确定在巴西中南部地区用因子k表示的土壤碳损失的空间变异结构及其与甘蔗作物的土壤属性的关系。实验在圣保罗州莫图卡（MOT），瓜里巴（GUA）和普拉多波利斯-SP（PAD）和马托的Aparecida do Taboado（APT）的商业甘蔗种植区进行南格罗索州。土壤CO ₂的测量LI-COR系统（LI-8100）在研究区域记录了排放（FCO2）。多元方法表明，两个主要成分（PC1和PC2）分别解释了所研究区域数据集中包含的总变异性的55％至68％。土壤物理属性在PC1内表现出区分能力，并表明充气孔隙空间和土壤含水量之间存在对比。在PC2中，化学属性指示阳离子交换容量和有效磷含量的共同作用。PAD和APT区域在因子k和PC1之间呈现负的重要空间格局。对于GUA和APT中k和PC2之间的空间模式，出现了负相关和显着相关的值。结果表明，土壤碳积累潜力在小范围内具有较高的空间变异性。因此，在同一区域内，因子k的空间格局发生了变化，在原甘蔗种植系统中呈现出具有潜在积累或碳源的区域，从而能够在同一生产区域内进行特定管理。