中国农业科学 ›› 2021, Vol. 54 ›› Issue (23): 5054-5067.doi: 10.3864/j.issn.0578-1752.2021.23.011

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

长期少免耕与氮肥减量对全膜双垄沟播玉米产量及碳排放的调控作用

周永杰1,2(),谢军红1,2(),李玲玲1,2,王林林1,2,罗珠珠2,3,王进斌1,2   

  1. 1甘肃农业大学农学院,兰州 730070
    2省部共建干旱生境作物学国家重点实验室(甘肃农业大学),兰州730070
    3甘肃农业大学资源与环境学院,兰州 730070
  • 收稿日期:2020-11-30 接受日期:2021-02-02 出版日期:2021-12-01 发布日期:2021-12-06
  • 通讯作者: 谢军红
  • 作者简介:周永杰,E-mail: 1109818358@qq.com
  • 基金资助:
    甘肃省科技重大专项(20ZD7NA007);甘肃农业大学青年导师基金项目(GAU-QDFC-2020-03);甘肃省科技计划项目(20JR5RA033);中央引导地方科技发展专项资金和甘肃省国际科技合作基地项目(GSPT-2018-56);中央引导地方科技发展专项(ZCYD-2020)

Effects of Long-Term Reduce/Zero Tillage and Nitrogen Fertilizer Reducing on Maize Yield and Soil Carbon Emission Under Fully Plastic Mulched Ridge-Furrow Planting System

ZHOU YongJie1,2(),XIE JunHong1,2(),LI LingLing1,2,WANG LinLin1,2,LUO ZhuZhu2,3,WANG JinBin1,2   

  1. 1College of Agronomy, Gansu Agricultural University, Lanzhou 730070
    2State Key Laboratory of Aridland Crop Science (Gansu Agricultural University), Lanzhou 730070
    3College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070
  • Received:2020-11-30 Accepted:2021-02-02 Online:2021-12-01 Published:2021-12-06
  • Contact: JunHong XIE

摘要:

【目的】明确氮肥减量条件下耕作方式对土壤呼吸、碳排放、作物产量的影响,揭示玉米生长与土壤碳排放的关系。【方法】于2018—2019年依托2012年布设于甘肃农业大学旱作农业综合实验站的耕作方式及氮肥减量长期定位试验。本试验以具有良好集雨抑蒸、增温保墒作用的全膜双垄沟播技术为前提,采取二因素裂区设计,主区为4种耕作方式:翻耕(T1);旋耕(T2);深松耕(T3)和免耕(T4),副区处理为两个施氮水平:氮肥减量(N1:基施氮200 kg·hm-2)和传统施氮(N2:基施200 kg·hm-2+拔节期施100 kg·hm-2)。研究不同处理的玉米生长、土壤呼吸速率特征、碳排放量和土壤有机碳含量的变化,分析碳排放效率 (CEE) 及净生态系统生产力 (NEP)。【结果】(1) 耕作方式及施氮水平显著影响全膜双垄沟播玉米的生长,耕作方式对干物质积累的影响主要在灌浆期和成熟期,免耕处理显著提高了该时期的干物质积累量、生长率和净同化速率,较其他耕作方式籽粒产量提高2%—15%;施氮水平在拔节期—开花期对干物质的影响较大,但同一耕作方式下N1与 N2水平的产量差异不显著。(2)土壤呼吸速率呈先升高后降低的单峰曲线,在大喇叭口期—开花期达到峰值,耕作方式对土壤呼吸、碳排放量及碳排放效率的影响大于施氮水平,免耕处理的土壤呼吸速率较旋耕、翻耕和深松耕分别降低了4.3%、12.9%和24.3%,总碳排放量降低了21.5%、13.4%和31.2%,碳排放效率提高26.5%—55.9%;免耕减施氮肥较其他处理碳排放总量降低489—1 917.5 kg·hm-2,碳排放效率提高了20.1%—56.2%。(3) 所有处理均表现为大气CO2的“汇”,但免耕和减施氮肥表现出更强的碳汇效应,与传统翻耕相比,免耕处理0—5 cm土层有机碳含量增加了11.3%(P<0.05),与传统施氮相比,氮肥减量水平下0—10 cm土层的有机碳含量提高了5.8%(P<0.05)。(4)全膜双垄沟播玉米碳排放效率与干物质积累量、生长率和净同化率呈显著正相关关系,玉米碳排放效率与土壤有机碳含量呈极显著负相关,其原因主要是耕作方式和氮肥减量促进了玉米光合能力,从而捕获更多CO2,进而提高了玉米固碳能力。【结论】在472—491 mm的年降水条件下,免耕结合氮肥减量(基施氮200 kg·hm-2)能提高玉米产量、土壤有机碳含量,降低碳排放总量,提高碳排放效率,是陇中黄土高原全膜双垄沟播玉米一项绿色增产技术,建议在生产中使用。

关键词: 玉米, 免耕, 减氮, 土壤呼吸, 碳平衡, 产量

Abstract:

【Objective】 The effects of tillage practices on soil respiration, carbon emission and crop yield under nitrogen reduction were clarified, and the relationship between maize growth and soil carbon emission was revealed.【Method】The long-term tillage practices and reduced fertilization experiment initiated in 2012 within two-year (2018-2019) was conducted at the Rainfed Agricultural Experimental Station of the Gansu Agricultural University in the Gansu province of northwestern China. This experiment is based on the technology of full-film double-ridge and furrow sowing maize with good effect of collecting rainfall and inhibiting evaporation and increasing temperature and soil moisture. The experiment adopted the split plot design, and the main plots were four tillage practices (conventional tillage, rotary tillage, subsoiling, and no-tillage) and the subplot were two nitrogen application levels (nitrogen reduction (200 kg·hm-2) and conventional nitrogen application (300 kg·hm-2)). Based on this experiment, the maize growth, soil respiration rate, carbon emission and soil organic carbon content, carbon emission efficiency (CEE) and net ecosystem productivity (NEP) were assessed.【Result】(1) Tillage practice and nitrogen application level significantly affected the growth of maize, and the effect of tillage practice on dry matter accumulation was mainly in the filling stage and maturity stage. No tillage treatment significantly improved the dry matter accumulation, growth rate and net assimilation rate at these stages, which increased grain yield by 2%-15% compared with other tillage practices; nitrogen application level had a greater effect on dry matter during jointing flowering stage, but the same effect was observed, and there was no significant difference in yield between N1 and N2 under the same tillage practice. (2) The soil respiration rate showed a single-peak curve that first increased and then decreased, reaching its peak in the big bell mouth-flowering period. The effects of tillage practices on soil respiration, carbon emissions and carbon emission efficiency were greater than the nitrogen levels. Compared with rotary tillage, tillage and subsoiling, no tillage decreased soil respiration rate by 4.3%, 12.9% and 24.3%, respectively, and total carbon emission decreased by 21.5%, 13.4% and 31.2%, respectively, while carbon emission efficiency increased by 26.5%-55.9%. Compared with other treatments, no tillage combined with nitrogen reduction reduced total nitrogen and carbon emission by 489-1917.5 kg·hm-2, while the carbon emission efficiency increased by 20.1%-56.2%. (3) All treatments showed a “sink” of atmospheric CO2, but no-tillage and reduced nitrogen fertilizer showed a stronger carbon sink effect. The organic carbon content in 0-5 cm soil layer was significantly increased by 11.3% (P<0.05) compared with conventional tillage; the organic carbon content in 0-10 cm soil layer was increased by 5.8% (P<0.05) compared with conventional tillage. (4) There was a significant positive correlation between the efficiency of carbon emissions and the accumulation of dry matter, the rate of growth and net assimilation rate, and a significant negative correlation between the efficiency of carbon emissions and the organic carbon of the soil. This was mainly because the cultivation practices and application of nitrogen promoted maize’s photosynthetic ability, obtained more CO2, and enhanced maize’s capacity for carbon fixation. 【Conclusion】 Under the condition of 472-491 mm annual precipitation, no tillage combined with nitrogen reduction (200 kg·hm-2) could improve maize yield, improve soil organic carbon content, reduce total carbon emission, and improve carbon emission efficiency. A green yield-increasing technology of full-film double-ridge and furrow sowing maize in the Loess Plateau of Longzhong was recommended to be used in production.

Key words: maize, no-tillage, nitrogen fertilizer reducing, soil respiration, carbon balance, yield