|
| Nitric Oxide Emission and Its Influencing Factors in Two Paddy-upland Rotation Systems in Chengdu Plain of Sichuan Basin |
| Received:February 28, 2015 |
| View Full Text View/Add Comment Download reader |
| KeyWord:NO emissions;paddy-upland rotation system;controlling factors;soil water-heat conditions |
| Author Name | Affiliation | | YU Ya-jun | College of Geography Sciences of Shanxi Normal University, Shanxi Linfen 041004, China | | ZHU Bo | Institute of Mountain Hazards and Environment, CAS, Chengdu 610041, China |
|
| Hits: 2303 |
| Download times: 101 |
| Abstract: |
| Soil is an important source of global nitric oxide(NO) emissions. Here NO emission rates were monitored in paddy-upland rotation systems from November, 2005 to May, 2006, using static chamber method/chemiluminescence NOX analyzer. At fertilization rate of N150 kg·hm-2, the mean NO emission flux was 8.3±3.7 μg·m-2·h-1 and 7.2±5.4 μg·m-2·h-1 in rice-wheat and rice-rapeseed rotation systems, respectively. The total NO emission was respectively 58.1±29.2 kg·hm-2 and 37.4±14.0 kg·hm-2. The NO emission flux increased significantly following N application, with more NO fluxes in rice season than in wheat or rapeseed season. More than half of total amount of NO emissions was produced in the rice season. Ploughing caused high NO emission rates in the fallow season after crop harvests, implying that reduced ploughing would effectively reduce NO emissions in fallow season. Soil temperature and moisture were found to be two important factors regulating NO emissions. The NO emission flux was linearly related with soil temperature. However, soil moisture influences on NO emissions were more complicated:increasing soil moisture promoted the NO emissions in wheat and rapeseed seasons with relative dry soil conditions, while NO emissions was inhibited by flooding in rice season with high soil moisture. Poor combination of water and heat conditions caused soil NO negative emissions(soil absorption). |
|
|
|
