N2 O Emissions from Tea Plantations with Sorghum Intercropping and Application of Big Urea Pills

Abstract

A large amount of fertilizers are applied to the tea plantations resulting in high nitrous oxide (N2O) emissions. The area of Chinese tea plantations has been expanding in recent years, making them an important source of agricultural N2O emissions. There is an urgent need for effective mitigation measures for N2O emissions from tea plantations. In this study, the N2O emission flux and related environmental factors are measured in Chinese mid-subtropical typical hilly tea plantation under three kinds of management measures, namely intercropping sorghum, applying big urea pills, and under conventional fertilization conditions. The aim of this experiment is to determine the main factors controlling N2O emissions from the soils of the tea plantation and confirm the true effectiveness of the proposed N2O emission mitigation measures. The results of a 2-year field experiment show that:① N2O emissions were significantly correlated with soil chemical properties, temperature and rainfall, interaction between soil physical and chemical properties; soil chemical properties have the greatest impact on soil N2O emissions. The concentration of soil NO3--N is the most important factor determining the size of N2O flux in the tea plantation. The most important task of N2O emission mitigation research in the tea plantation is to reduce the concentration of soil NO3--N; ② sorghum intercropping reduces N2O emissions by 51.2% while not affecting the tea yield. From the perspective of mitigating global warming, sorghum intercropping is the best tea plantation management measure per the results of this study; ③ applying big urea pills effectively increases tea yield while simultaneously reducing the N2O emissions by 34.7%. From the perspective of balancing economic benefits as well as mitigating global warming, application of big urea pills is undoubtedly the best tea plantation management measure as indicated by this study.