## 1 Introduction
Despite its limitations, the EL-FAME method can be used to describe the size, and structure of microbial communities in soils that may rapidly respond to plant and soil characteristics changes because of different nutrient availability, substrate's quality and quantity, root exudates, and rhizodeposits [20]. Furthermore, the method is used as an indicator of the biological component for soil health assessments [21; 22]. Studies suggest elevated microbial biomass and significant microbial community composition and function variations have occurred due to biochar addition to soils [23]. Studies using phospholipid fatty acid (PLGA) analysis found increased concentrations of gram-positive bacteria and Actinobacteria biomarkers [24; 25] and elevated fungal/bacterial ratios [24]. Nevertheless, biochar was responsible for decreasing the gram-positive/gram-negative relationship in another study [26]. Soil enzyme activities (EAs) are used as key soil health indicators of soil function owing to the sensitivity of enzymes to changes in soil nutrient transformation and SOM dynamics due to variations in land use, management, pollution, and climate [27]. Since the stabilization of OM additions into soil organic carbon (SOC) is mediated by microbial processing [28; 29], the activity of enzymes that transform SOM and other minerals has been proposed to be a fundamental driver of elemental turnover. As a result, assays of EAs are useful when describing responses to management practices such as tillage and OM inputs because of their fast response, sensitivity, and adaptability to ecosystem changes [28]. Four EAs have been evaluated as soil health indicators due to the essential roles played in the cycling reactions that release bioavailable C (\(\beta\)-glucosidase), N, and C (\(\beta\)-glucosidaseaminidase), P (acid phosphomonoesterase), and S (arylsulfatase) nutrients [30]. [PERSON] et al. [31] studied the impact of pinewood biochar on soils under maize production. They found that biochar increased \(\beta\)-glucosidaseaminidase activity but decreased the activities of \(\beta\)-glucosidase and acid phosphatase. However, in another study by [PERSON] et al. [32], biochar's addition had different results depending on soil characteristics and EA assayed. For example, \(\beta\)-glucosidase activity increased with a 2% biochar addition in sandy loam and silt loam soils while the activity decreased in sandy soil. Additional studies evaluatingpinewood biochar's effects on different soil types and crop production systems using the four EAs as proxies representing C, N, P, and S cycling status are needed. In the Sandhills region of North Carolina, peach-tree production is a critical economic sector. These soils are fragile due to their sandy texture and low SOM content (0.60%), and pinewood biochar amendments can improve soil health. This project's related work has already demonstrated that pinewood biochar increased TC and macro-aggregates fractions, while active C decreased. Moreover, biochar significantly increased soil activity, as revealed by the biogeochemical cycle index, CNPS activity [33]. This study evaluated pinewood biochar's impact at different rates on microbial community structure and nutrient cycling in soils under peach trees. This information can help producers optimize the rates of biochar applications to soils. Soil physicochemical properties, including the SOM dynamics, were also used to explore the potential mechanisms influencing the changes in the soil microbial community. Based on previous results [33], we hypothesized that biochar would alter the soil microbial community structure and the soil EAs involved in nutrient cycling based on the depth of incorporation (incorporation and surface) and application rates (5% and 10%).