Intercropping Peanut under Forests Can Reduce Soil N2O Emissions in Karst Desertification Control

Abstract

In the process of vegetation restoration for karst desertification management, the lack of scientific and rational intercropping technology and the blind application of large amounts of nitrogen fertilizer have made the soil the main source of atmospheric N2O in this region. How soil N2O emissions vary under different intercropping modes is a scientific question worthy of study. This study took a three-year-old loquat (Eribotrya japonica L.) artificial forest in the karst plateau canyon as the experimental site and designed loquat intercropping with peanut, corn, and sweet potato (Ipomoeabatatas (L.) Lam.) as well as non-intercropping to analyze the differences in soil physicochemical properties and greenhouse gas emissions under different intercropping patterns. The results showed that intercropping with peanut significantly increased loquat yield, soil moisture, temperature, SOC, MBC, TN, and MBN content. The emissions of N2O and CO2were mainly positively correlated with soil moisture and temperature, while CH4 showed a negative correlation with soil moisture and soil temperature. The soil absorbed CH4 in the control of karst desertification. Karst area soils exhibited higher N2O emissions. Intercropping patterns significantly influenced soil N2O emissions, with N2O-N cumulative emissions ranging from 5.28 to 8.13 kg·hm−2 under different intercropping conditions. The lowest N2O-N cumulative emissions were observed for peanut intercropped under the forest. The peak N2O emission occurred in April 2022, which may be attributed to the higher rainfall and soil moisture during that month. Intercropping peanut with loquat significantly reduced the global warming potential. Therefore, intercropping peanut in young forests can improve soil water and fertilizer conditions, reduce soil N2O emissions and global warming potential, and serve as a nitrogen fixation and emission reduction technique suitable for karst desertification areas.