Stoichiometry of soil carbon, nitrogen, and phosphorus in farmland soils in southern China: Spatial pattern and related dominates

• The farmland soil in Jiangxi Province is facing a serious threat of acidification. • parental materials and soil group greatly affect soil C, N and P stoichiometry. • The MAT and MAP is significantly related to soil C, N and P stoichiometry. • The cropping system has essential effect on soil C, N and P stoichiometry. • Straw return could clearly increase the soil N:P ratio. Soil carbon (C), nitrogen (N), and phosphorus (P) contents and its stoichiometry are important indicators of the elemental balance in ecological interactions and processes. Farmland usually is featured by extensive anthropogenic actions which profoundly alters the soil C, N, P contents and its stoichiometry. However, it remains largely unknown how the soil C, N and P stoichiometry in farmlands is comprehensively affected by natural factors including parental material, soil types, annual mean temperature, annual precipitation, and soil management measures such as crop rotation and straw return at large spatial scale. The main aim of this study is to analyze the summary statistics, spatial variability, as well as main controls of soil C, N and P stoichiometry in farmland of the whole Jiangxi Province, which is one of the most important food production base. Our results found that the average concentration of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) is 17.91, 1.58 and 0.52 g kg −1 in farmland soil of Jiangxi Province, respectively. The averaged value of the soil C:N, the soil C:P ratio, and the soil N:P ratio is 11.73, 38.31 and 3.38, correspondingly. Great differences were detected for C, N and P stoichiometry in farmland soil derived from different parental materials or different soil groups. The mean annual temperature (MAT) is significantly and negatively related to soil C:N ratio, soil C:P ratio as well as soil N:P ratio while the annual precipitation (MAP) is significantly and positively related to soil C:P ratio, soil N:P ratio but significantly and negatively related to soil C:N ratio. The structural equation model analysis showed that soil properties and soil management have greater influences on soil C, N and P stoichiometry than climate and lithology. Our results could provide important implications for soil management and agricultural production.