Publication date: 15 August 2018
Source:Geoderma, Volume 324
Author(s): Yongxiang Yu, Hongtao Jia, Chengyi Zhao
Plastic film has been widely applied to address water shortages by reducing soil evaporation in arid and semi-arid regions, but it simultaneously affects soil nitrous oxide (N2 O) emissions. Moreover, after the application of plastic film, the ability of nitrification inhibitor to reduce N2 O emissions remains unclear. In this study, the chamber method was used to measure N2 O emissions and a modified diffusion equilibrium sampler was used to obtain N2 O concentrations in an oasis cotton field. Non-mulched and mulched treatments were used to investigate the influence of plastic mulching on soil N2 O dynamics, and mulched plus nitrapyrin treatment was used to evaluate the ability of nitrapyrin to reduce N2 O emissions under plastic mulching. Moreover, we also estimated the net economic return and cost related to an eventual environmental taxation on N2 O emission of these practices. In all treatments, the ridge soil was the origin of most N2 O (82–87%) emissions, which remained at low levels during the non-fertigation period (ranging from 0.4–17.1 g N ha−1 day−1) and sharply increased after the split application of urea; emissions during the fertigation periods accounted for 57–85% of the total N2 O emissions in all treatments. Compared with the non-mulched treatment, the use of plastic film is a “win-win” strategy for both agricultural income (net economic returns increased by $436–522 ha−1 year−1) and N2 O mitigation (emissions reduced by 19–28%), even without incentives. Although the addition of nitrapyrin to the urea reduced the cumulative N2 O emissions by 23–39% under plastic mulching, and therefore reduced the costs related to an eventual environmental taxation on N2 O emission by approximately $2 ha−1 year−1, this benefit could not compensate for the additional cost of inputting nitrapyrin ($24 ha−1 year−1) because this technique did not have a significant effect on cotton yields. Therefore, the use of nitrapyrin is probably a “lose-win” strategy for farmers and N2 O mitigation and not suitable for reducing N2 O emissions in oasis cotton fields.
Source:Geoderma, Volume 324
Author(s): Yongxiang Yu, Hongtao Jia, Chengyi Zhao
