不同耕作方式下旱作玉米田土壤呼吸及其影响因素

为揭示不同耕作方式对旱作玉米田土壤呼吸的影响,对比研究深松耕、免耕、旋耕和翻耕4种耕作方式下土壤呼吸速率的动态变化及其与土壤水分、温度、有机质、全氮、pH值等的关系。结果表明,夏玉米生长季,4种耕作方式下土壤呼吸速率随生育时期均呈先增加后降低的趋势,平均土壤呼吸速率为深松耕>翻耕>旋耕>免耕;播种前至拔节期土壤温度为翻耕>深松耕>旋耕>免耕,抽雄期至成熟收获期为免耕>旋耕>深松耕>翻耕;各耕作方式下0～20cm层土壤有机质、全氮均逐渐增加,与免耕比较,翻耕有机质和全氮均降低;生育前期土壤pH值波动明显,抽雄期后趋于平缓,土壤pH值平均值为翻耕>旋耕>免耕>深松耕。各影响因素与土壤呼吸速率相关分析表明,深松耕和翻耕土壤水分、温度与土壤呼吸速率呈显著或极显著正相关;有机质与土壤呼吸速率呈负相关,且与深松耕措施下土壤呼吸速率呈显著负相关;除免耕外,其他耕作方式下土壤全氮、pH值与土壤呼吸呈负相关。该研究可为补充完善土壤呼吸排放机理、评估区域碳收支平衡及制定科学有效的土壤碳调控管理措施提供依据。

Soil respiration and its affecting factors in dry-land maize field under different tillage systems

To explore the effects of different tillage systems on soil reparation during the summer maize crop growing season, the tillage systems included deep tillage (DT), no tillage (NT), rotary tillage (RT) and plow tillage (PT) was designed. The soil respiration, its affecting factors and the relationship of soil respiration rate with soil moisture, soil temperature, soil organic matter, total nitrogen and soil pH was elucidated. The results indicated that soil respiration rate was first increased then decreased during the whole crop period in all kinds of tillage systems. The maximum of soil respiration rate was DT, followed by PT, RT, NT. Soil temperature of PT was the highest, followed by DT, RT, NT from seeding to jointing stage; that of NT was the highest, followed by RT, DT, PT from tasseling to maturity stage. Soil organic matter, and Total nitrogen were gradually increased from planting to flowering stage, those of PT.was higher than those of NT. Soil pH value were significantly different during the growth stages, that of PT was the maximum, followed by RT, NT, DT. Soil moisture and soil temperature were significant correlated with soil respiration (P>0.05). DT and PT were significantly correlated with soil moisture and soil temperature; soil organic matter were negatively correlated with soil respiration rate, and similarly significantly negative correlation was recorded between soil organic matter contents of DT and soil respiration rate. The negative correlations (P>0.05) were recorded between total nitrogen and soil pH value for soil respiration under DT, RT, PT. The study provides a guideline for the complement of soil respiration and emission mechanism, the assessment of regional carbon input and output balance, and the establishment of feasible soil carbon regulation.