• ISSN 1008-505X
  • CN 11-3996/S

秸秆还田对关中地区麦玉轮作田N2O排放的短期效应

Short-term effects of straw return on N2O emissions from wheat and maize rotation fields in Guanzhong area

    摘要
  • 摘要:
    目的 分析环境因子和土壤N2O排放对短期秸秆还田的响应，以更准确地评价化肥施用下短期秸秆还田的增减排效益。
    方法 于2020—2021年在关中地区开展了小麦–玉米轮作田间试验。采取双因素裂区设计，主处理为秸秆还田(W1)与不还田(W0)，副处理为不施肥(W1、W0)、施氮肥(W1N、W0N)和施氮磷肥(W1NP、W0NP)。测定了土壤含水量、温度、NO3−-N、NH4+-N、速效磷含量及N2O排放通量，调查了作物产量，并探讨了土壤N2O排放与环境因子之间的关系。
    结果 相比W0，W1处理土壤含水量提高了1.1%～16.2%；W1N处理的土壤NO3−-N含量峰值较W0N高17.6%～30.5%。4个施肥处理的土壤NO3−-N和NH4+-N含量随生育时期推进先迅速上升，然后缓慢下降，施氮肥处理的土壤NO3−-N峰值比施氮磷肥处理高17.0%～20.8%。W1NP与W0NP处理土壤的速效磷含量随生育期推进先上升后缓慢下降，平均速效磷含量显著高于处理W0、W1、W0N和W1N (P<0.05)。冬小麦季和夏玉米季分别在施肥后第6和第12天土壤N2O排放通量达到峰值。W1N、W1NP的土壤N2O排放峰值分别比W0N、W0NP高5.0%和38.5%，全年累计排放量分别比W0N、W0NP高291.13和379.99 g/hm2 (P<0.05)；W1N处理的土壤N2O全年累计排放量比W1NP处理高298.14 g/hm2，W0N处理的土壤N2O全年累计排放量比W0NP高386.99 g/hm2，施氮磷肥处理的排放峰值比施氮肥处理低2.43%～54.67%。相关性分析发现，N2O排放通量与土壤温度、含水量、NO3−-N、NH4+-N、速效磷含量呈极显著正相关(P<0.01)。各处理N2O排放强度表现为：相同秸秆还田条件下，施氮肥>施氮磷肥>不施肥处理；相同施肥条件下，秸秆还田>不还田处理。
    结论 不论是否秸秆还田，氮磷肥配施均提高了土壤速效磷含量，降低了NO3−-N峰值，因而降低了N2O年累积排放量。秸秆还田后短期内虽然也提高了土壤速效磷含量，但其较高的土壤含水量和NO3−-N含量导致更高的N2O排放通量和农田N2O累计排放量。因此，评价秸秆还田在农业可持续发展中的生态与生产效益时，也应考虑其还田后短期存在的不利影响。

     

    Abstract:
    Objectives The responses of environmental factors and soil N2O emissions to short-term straw return were analyzed for more accurate evaluation of the benefits of short-term straw return in terms of N2O emissions under fertilization.
    Methods A field trial was conducted in Guanzhong area, Shaanxi Province, from 2020 to 2021. The cropping system was winter wheat and summer maize rotation. A two-factor split-zone design was adopted, with the main factor of straw return (W1) and no return (W0), and the sub-factor of fertilization, composing 6 treatments, as: no fertilizer (W1, W0), nitrogen fertilizer (W1N, W0N) and nitrogen and phosphorus fertilizer (W1NP, W0NP). Soil water content, temperature, NO3−-N, NH4+-N, and available P content, N2O emission fluxes were measured, crop yields were investigated, and the relationships between soil N2O emissions and environmental factors were explored.
    Results The soil water content in W1 treatment was 1.1%–16.3% higher than in W0, and the peak soil NO3--N content in W1N treatment was 17.6%–30.5% higher than in W0N. The soil NO3−-N and NH4+-N contents of two N and two NP treatments first increased rapidly and then decreased slowly as the growth period progressed, and the peak soil NO3−-N of N treatments was 17.0%−20.8% higher than that of NP treatment. The soil available P content in NP treatments increased rapidly and then decreased slowly as the growth period progressed, and significantly higher than those in no fertilizer and N treatments on average. The soil N2O emission fluxes arrived peaks at 6 days and 12 days after fertilization in winter wheat and summer maize seasons, respectively. Compared with W0N and W0NP, W1N and W1NP increased the peak soil N2O emissions by 5.0% and 38.5%, and the annually cumulative N2O emissions by 291.13 g/hm2 and 379.99 g/hm2, respectively (P<0.05). The cumulative annual soil N2O emission in treatment W1N was 298.14 g/hm2 higher than in W1NP (P<0.05). W1NP decreased 2.43% and 298.14 g/hm2 of the peak and cumulative annual N2O emission, compare to W1N, while W0NP decreased 54.67% and 386.99 g/hm2 of peak and cumulative annual N2O emission, compared to W0N . Correlation analysis revealed that N2O emission fluxes were positively correlated with soil temperature and water content in maze season, and NO3−-N, NH4+-N, and available P contents in both maize and wheat seasons (P<0.01). Under the same straw return condition, the N2O emission intensity showed descent order of N fertilization, NP application, and no fertilization. Under the same fertilization, the N2O emission intensity with straw return was higher than without straw return
    Conclusions Whether straw was returned to the field or not, the combined N and P application was more effective in reducing cumulative N2O emissions than N fertilizer alone, as the increased soil available P content and lower soil NO3−-N peak content. Although straw returning to the field also increased the soil available phosphorus content in the short term, its higher soil moisture content and NO3−-N content led to higher N2O emission flux and cumulative N2O emissions from farmland. This short term adverse ecological impact should be considered in the evaluation of straw return.

     

    • HTML全文
    • 参考文献(43)
    • 相关文章
    • 施引文献
  • 资源附件(0)

/

返回文章
返回