保护性耕作对旱作农田干湿交替过程中土壤呼吸速率的影响

发布时间：2018-03-28 17:21

  本文选题：免耕　切入点：秸秆覆盖　出处：《中国农业科学》2017年24期

【摘要】：【目的】探讨免耕及秸秆覆盖等保护性耕作措施对旱作农田干湿交替过程中土壤呼吸速率的影响。【方法】基于设在陇东黄土高原的长期草田轮作定位试验,试验开始于2001年,包括传统耕作(T,翻耕并移除秸秆)、耕作覆盖(TS,翻耕之后覆盖秸秆)、免耕移除秸秆(NT,不翻耕但除去秸秆)和免耕(NTS,不翻耕且保留秸秆)4个处理。2014年7—8月干湿交替阶段季采用LI-8150多通道土壤碳通量测量系统对农田土壤呼吸速率、土壤温度和含水量进行连续原位测定。【结果】T、TS、NT和NTS处理干旱阶段的平均土壤呼吸速率分别为2.16、3.56、2.26和2.45μmol·m~(-2)·s~(-1),湿润阶段分别为2.09、5.31、2.80和3.56μmol·m~(-2)·s~(-1)。降雨初期秸秆覆盖处理(TS和NTS)土壤呼吸速率动态变化与无秸秆覆盖处理(NT和T)具有显著差异。干湿交替过程中,干旱阶段土壤呼吸速率与土壤温度(19.1—28.2℃)呈负相关、与土壤含水量呈正相关关系;湿润阶段则相反,且土壤含水量对土壤呼吸速率的解释程度降低。土壤呼吸速率在湿润阶段日动态波动较大,其温度敏感性(Q10)在T、TS、NT和NTS处理下分别为1.37、1.24、1.31和1.25;干旱阶段土壤呼吸速率日动态平缓,Q10值低于1.0。【结论】长期保护性耕作提高了农田的土壤呼吸速率,且秸秆覆盖处理比免耕措施提高土壤呼吸速率的效应更加显著。秸秆覆盖能够有效平抑土壤水分和温度的变化,提高土壤呼吸速率,降低土壤呼吸的温度敏感性。论文明确了干湿条件下旱作农田土壤呼吸动态及其影响因素,对准确量化旱作农田碳通量具有积极意义。
[Abstract]:[objective] to investigate the effect of conservation tillage measures such as no-tillage and straw mulch on soil respiration rate during dry-wet rotation in dry-wet field. [methods] based on the long-term rotation experiment in Loess Plateau of East Gansu Province, the experiment began in 2001. These treatments include traditional tillage, tillage and removal of straw stalks, tillage mulching with TSs, mulch after tillage, no tillage removal of straw NTs, no tillage but removal of straw) and no tillage NTS, no tillage and retention of straw). LI-8150 multi-channel soil carbon flux measurement system was used to measure soil respiration rate. The soil temperature and water content were measured in situ continuously. [results] the average soil respiration rates of Tetsmont and NTS treatments in drought stage were 2.16 ~ 3.56 ~ 2.26 and 2.45 渭 mol / m ~ (-1) ~ (-1) ~ (-1), respectively, and those in wet stage were 2.09 ~ 5.31 ~ 2.80 and 3.56 渭 mol / m ~ (-2) 路s ~ (-1) 路s ~ (-1), respectively. TS and NTS were treated by straw mulching in the early stage of rainfall. There was significant difference between the dynamic change of rate and the treatment of NT and T without straw mulch. Soil respiration rate was negatively correlated with soil temperature (19.1-28.2 鈩，

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