Early response of organic matter dynamics to pine‐biochar in sandy soil under peach trees

Biochar may enhance soil health in sandy soils under peach [Prunus persica (L.) Batsch] tree production. A study was initiated in the Sandhills of North Carolina by applying pine-biochar at two different rates (5 and 10%, v/v) and types of application (incorporation to 30 cm [-Inc] and surface [-Sur]) in 2017. Soil organic matter (SOM) dynamics was assessed via soil organic carbon (SOC), total nitrogen (TN), permanganate-oxidizable carbon (POXC), aggregate fractions (macro-, micro-aggregates, and clay + silt particles), and enzyme activities (CNPS activity) at 0-15 and 15-30 cm in 2018 and 2019. After the first year of pine-biochar application, POXC decreased in all biochar treatments, SOC was higher in the 10%-Inc treatment, whereas CNPS activities and macroaggregates were highest in the 5%-Sur compared with the non-treated control. These results suggest early changes in SOM dynamics and biogeochemical cycling and have the potential to guide producers with the long-term application of pine-biochar to sandy soils.