| 摘要: |
| 【目的】研究施氮和土壤水热条件对河西绿洲灌区休耕季小麦玉米间作农田土壤N2O排放的影响。【方法】依托河西绿洲灌区地下淋溶长期定位监测试验，设置CK（不施肥）、CONV（常规施肥）、OPT（优化施肥）、OPT-N（减量施氮）和OPT+N（增量施氮）5个处理，采用静态箱-气相色谱法在休耕季监测小麦玉米间作农田土壤N2O通量动态变化，并建立二次多项式逐步回归方程，绘制交互效应曲面图。【结果】整个休耕季，小麦玉米间作农田是土壤N2O排放的弱源，土壤反硝化过程起主要作用。2018年11月中旬—2019年2月中旬，N2O通量总体表现为吸收，CONV处理和OPT+N处理虽有较高的N2O排放，但是处理间N2O通量排放差异未达显著水平（P>0.05）。在冬灌后，CONV、OPT、OPT-N、OPT+N处理N2O排放呈增长趋势，CK的N2O通量表现为吸收。通过交互效应曲面图发现10 cm地温与土壤N2O排放关联度最大，以及在交互作用的影响下，休耕季10 cm土壤地温与土壤N2O排放呈相反趋势。【结论】休耕季小麦玉米间作农田土壤N2O排放受生长季施肥影响较小，受土壤水热条件的影响较大。 |
| 关键词: 施氮；土壤；灌区；休耕季；小麦玉米间作；N2O |
| DOI：10.13522/j.cnki.ggps.2020002 |
| 分类号: |
| 基金项目: |
|
| Effects of Nitrogen Application and Soil Hydrothermal Conditions on N2O Emission from Farmland during Fallow Season |
|
LIU Shutong, MA Zhongming, WANG Zhiqi, ZHAO Fan, JIN Junmin
|
|
1.College of Agronomy/Gansu Provincial Key Laboratory of Arid Land Crop Science, Gansu Agricultural University,Lanzhou 730070, China; 2.Gansu Academy of Agricultural Sciences, Lanzhou 730070, China;
3.Yuzhong County Agricultural Technology Extension Center, Yuzhong 730100, China；4.Soil and Fertilizer and Water-saving Institute, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China;
5. Institute of Biology, Gansu Academy of Sciences, Lanzhou 730000, China
|
| Abstract: |
| 【Objective】The objective of this paper is to study the effects of fertilization and soil hydrothermal conditions on N2O emission from wheat-maize intercropping farmland.【Method】Based on the long-term monitoring experiment of underground leaching in Hexi oasis irrigation area, five treatments, CK (no fertilization), CONV(conventional fertilization), OPT (optimized fertilization), OPT-N (reduced nitrogen application) and OPT+N (incremental nitrogen application) were selected, and static chamber-gas chromatography was adopted to monitor the soil N2O flux dynamics in wheat maize intercropping farmland during the fallow season, and we established the quadratic polynomial progressive regression equation and drew the interactive effect surface diagram.【Result】The results showed that wheat-maize intercropping fields were the weak source of soil N2O emission during the whole fallow season, and the denitrification process played an important role. From the mid- November 2018 to the mid-February 2019, the overall N2O flux is manifested as absorption. Although the treatment of CONV and OPT+N had higher N2O emissions, the differences of N2O flux emissions among the treatments were not significant (P>0.05). After winter irrigation, the N2O emissions treated by CONV, OPT, OPT-N and OPT+N showed an increasing trend, while the N2O flux treated by CK showed as absorption. After winter irrigation, N2O emissions of CONV, OPT, OPT-N and OPT+N treatments showed an increasing trend, and N2O flux of CK treatment showed absorption. It was found that the correlation between soil temperature of 10 cm and soil N2O emission was the highest, and under the influence of the interaction, the soil temperature of 10 cm in fallow season showed an opposite trend with soil N2O emission. 【Conclusion】The N2O emission of wheat-maize intercropping farmland in fallow season is less affected by fertilization in growing season and more affected by soil hydrothermal conditions. |
| Key words: nitrogen application; soil; Hexi oasis irrigation Area; fallow season; wheat-maize intercropping; N2O |
