Effect of no-tillage and conventional tillage practices on the nitrous oxide (N2O) emissions in an upland soil: soil N2O emission as affected by the fertilizer applications

The effect of no-tillage and conventional tillage practices on the nitrous oxide (N2O) emissions from the upland soil was evaluated in the cultivation of soybean in the temperate climate from June 2014 to September 2015 in Korea. In addition, we investigated the links between N2O emitted from field soil and different kinds of fertilizers. An experimental plot was composed of two main sectors that were no-tillage and conventional tillage, and then they were subdivided into four plots according to types of fertilizers: CF, chemical fertilizer, LP, liquid pig manure, HV, hairy vetch, and NF, non-fertilizer. The monthly averages of N2O emissions were significantly different from each other during the growing seasons of soybean; in July, N2O emission was significantly the highest, whereas, in September, its emission was the lowest (LSD, p = 0.05). In 2015, compared to those treatments in conventionally-tilled soils, the cumulative N2O emissions in NK, CF, HV, and LP of no-tilled soils were reduced by 20, 28.7, 35.7, and 28.1 %, respectively (LSD, p = 0.05). It was shown that N2O emission was significantly reduced in the different fertilizer treatments of no-tilled soils, compared to those of conventionally-tilled soils, respectively. Furthermore, the cumulative N2O emission in no-tilled soils was reduced by 0.03–0.09 kg N2O compared to that in tillage soils. It was found that soil N2O emission was about 11 % less in LP than in CF. Results obtained from our study indicate that the use of no-tillage practice and liquid pig manure, rather than tillage practice and chemical fertilizer, can decrease the N2O emission.