Response Characteristics of Soil Properties to Exogenous Carbon and Nitrification Inhibitor Addition with the application of Pig Urine

• 1、School of geographical Sciences, Fujian Normal University, Fuzhou 350117
• 2、Research Center for Eco-Environmental Research Sciences, Chinese Academy of Sciences, Beijing 100085

Abstract：Reducing nitrogen (N) losses from livestock and poultry urine and improving soil N retention are important concerns in agricultural environmental research. In this study, a 28-day short-term incubation experiment was conducted to investigate the effects of exogenous carbon and nitrification inhibitors on soil properties following pig urine application. Fresh or aged straw and biochar were used as exogenous carbon sources, combined with nitrification inhibitor treatments. The results showed that soil ammonium concentrations continuously decreased, whereas nitrate concentrations generally increased during incubation, with the most pronounced changes occurring between 3 and 7 days. Exogenous carbon addition significantly altered N transformation, and soil nitrate concentrations were lower in straw treatments than in biochar treatments at the later stage of incubation. Fresh straw exhibited a strong capacity to supply labile carbon, whereas biochar showed a greater capacity to buffer soil pH. Treatment with dicyandiamide resulted in significantly higher soil ammonium concentrations than the other treatments, indicating a certain degree of nitrification inhibition. Overall, the type and aging state of exogenous carbon may regulate soil N transformation by altering the availability of soil carbon and nitrogen and soil pH. These findings provide a theoretical basis for the rational application of exogenous carbon and regulation of soil N under pig urine return conditions.

Keywords： pig urine biochar straw nitrification inhibitor available nitrogen