稻鸭共作生态系统中N_2O排放及经济效益评价

Nitrous oxide emission from rice-duck complex ecosystem and the evaluation of its economic significance

稻鸭共作技术是中国传统农业的精华,研究稻鸭共作生态系统中N2O排放产生的环境效应并对其经济价值进行评价,为进一步开发利用这一经典农艺提供理论基础和实践依据。采用静态箱技术,研究稻鸭共作生态系统N2O排放规律,并运用增温潜势对稻鸭共作生态系统N2O排放的温室效应及经济效益进行了估算。结果表明,稻鸭共作生态系统N2O排放呈现明显的日变化和季节变化。N2O日变化与鸭子的活动呈现明显的相关性,其排放峰值出现在清晨和16:00;N2O季节变化幅度较大,排放峰值出现在水稻成熟期。在施用等量基肥条件下,稻鸭稻田排放的N2O高于常规稻田,其平均排放通量分别为(149.46±25.81)μg.m-.2h-1和(138.84±25.26)μg.m-.2h-1,产生的温室效应成本分别为283.14yuan.hm-2和265.47yuan.hm-2。除去N2O排放产生温室效应的环境成本,采用稻鸭生态种养技术的经济效益为7687.66yuan.hm-2,比常规不养鸭稻田增加1932.33yuan.hm-2。可见,稻鸭共作技术仍具有较好的推广价值。

The rice-duck ecological system is one of the classics practices from the traditional Chinese agriculture.Study on its economic significance and nitrous oxide emission of this practice can provide theoretical and practical basis for further development and utilization of this classical agricultural technique.Nitrous oxide emission from rice-duck complex ecosystem was measured in situ by using static chambers technique,and the greenhouse effect of nitrous oxide using global warming potentials（GWPs）and its economic significance were assessed.Results were shown that nitrous oxide emission from rice-duck complex ecosystem presented distinct diurnal and seasonal variation.Diurnal variation of nitrous oxide emission was highly correlated with the activities of ducklings.The peaks of nitrous oxide emissions were normally increased in the early morning and at 16：00 due to the frequent movement of ducklings at these time period.The seasonal variation was varying,and the peak of nitrous oxide emission appeared at the ripening stage.Under the same urea application as basal fertilizers,the nitrous oxide flux from RD was higher than that from CK,and the mean emission rate was about（149.46±25.81）μg·m-2·h-1 and（138.84±25.26）μg·m-2·h-1,respectively.The cost of greenhouse effect was 283.14 yuan·hm-2 and 265.47yuan·hm-2,respectively.In addition to the achieved economic benefits of 7687.66yuan·hm-2,which is 1932.33 yuan·hm-2 more than those who adopted a conventional without duck technique,respectively.Rice-duck complex ecosystem is still populated by farmer with its economy benefit.