Effects of Maize-Soybean Intercropping on Nitrous Oxide Emissions from a Silt Loam Soil in the North China Plain

Maize, a staple crop in the North China Plain, contributed substantially to agricultural nitrous oxide (N 2 O) emissions in this region. Many studies have focused on various agricultural management measures to reduce N 2 O emissions. However, few studies have investigated soil N 2 O emissions in intercropping systems. The objective of the current study was to investigate whether maize–soybean intercropping treatments could reduce N 2 O emission rates compared with monoculture treatment. This issue was investigated in two differently configured maize–soybean intercropping treatments: 2:2 intercropping (2M2S) and 2:1 intercrop (2MS) including monocultured maize (M) and soybean (S) using a static chamber method. The results showed that there was no distinct yield advantage for intercropping systems. Total N 2 O production from the various treatments was 0.15 ± 0.04–113.85 ± 12.75 μg m −2 min −1 . Cumulative N 2 O emission from the M treatment was 16.9 ± 2.3 kg ha −1 across the entire growing season (three and a half months), which was significantly higher than that of the 2M2S and 2MS treatments by 36.6% and 32.2%, respectively ( P −1 ) induced a considerable soil N 2 O flux. Short-term N 2 O emissions (within 1 week after the two N applications) accounted for 74.4–83.3% of total emissions. Soil moisture, temperature, and inorganic N were significantly correlated with soil N 2 O emissions ( R 2 = 0.246–0.365, n = 192, P 3 − and moisture could be decreased in intercropping treatments during the growing season. These results indicate that maize-soybean intercropping can reduce soil N 2 O emissions relative to monocultured maize.