摘要
设置大豆和棉花的盆栽试验,利用静态箱法采样和气相色谱技术测定作物生长期的土壤呼吸。结果表明,大豆与棉花生长下土壤呼吸速率变化与作物生长相一致,与生长时间呈极显著的二次曲线相关关系。裸土土壤呼吸速率的季节变化不明显,与时间的相关性弱。大豆土壤呼吸速率的峰值是棉花的2.4倍,出现时间也比棉花早。大豆土壤呼吸呈苗期<分枝期<成熟期<开花结荚期<鼓粒期,鼓粒期和开花结荚期的土壤呼吸占全生育期总量的82%,而生长时间只占全生育期的38.7%,大豆土壤呼吸总量是相应裸土的11.5倍。棉花土壤呼吸呈苗期<吐絮期<蕾期<花铃期,蕾期和花铃期土壤呼吸占全生育期的77.8%,生长时间只占全生育期的44.7%,棉花土壤呼吸总量是相应裸土的4.9倍。大豆全生育期的土壤呼吸总量和平均土壤呼吸速率分别是棉花的1.77倍和2.34倍。大豆和棉花生长时期根际呼吸对土壤呼吸的贡献分别为3.2%～95.8%和21.8%～88.0%,平均全生育期根际呼吸对土壤呼吸的贡献分别为91.3%和79.6%。大豆全生育期根际呼吸数量和平均根际呼吸速率分别是棉花的2.03倍和2.68倍。在种植作物的土壤中,土壤呼吸速率与气温呈显著的指数相关,而在裸土中,相关性不显著。氮肥对裸土的土壤呼吸无显著影响。总之,作物-土壤系统中,土壤呼吸受作物类型和生长时期控制,根际呼吸是土壤呼吸的主要部分,大豆由于共生固氮过程使得其土壤呼吸和根际呼吸的贡献显著高于棉花。
Soil respiration is an important factor in carbon cycle in ecosystem, which influences the concentration of CO2 in atmosphere. To understand effects on soil respiration in the leguminous and non-leguminous crops, we conducted a pot experiment planted soybean （Glycine max） and cotton （Gossypium spp）, and the soil respiration rate during crop growing season was sampled by static closed chamber method and analyzed by gas chromatography. The results showed that seasonal changes of soil respiration rate in cropped soil were in accord with crop growing and there were significant correlations of quadratic function between soil respiration rates and growing days of crops. While the seasonal changes of soil respiration rate in bare soils were not significant and their correlations to days after sowing were weak. The maximum soil respiration rate in soybean planted soil was 2.4 times as high as and appeared earlier than that in cotton planted soil. In the soil planted soybean, the respiration rate for growing stages was seedling branching ripening flowering-podding filling stages, the soil respiration during filling and flowering-podding stages contributed 82% of the total soil respiration, but the days of the growing stages accounted for only 38.7% of the entire growth period, while in cotton planted soil, that was seedling boll opening budding flowering and boll forming stages, soil respiration during budding, flowering and boll forming stages contributed 77.8% of the total soil respiration, but the days of the growing stages accounted for only 44.7% of entire growth period. The total soil respiration in soybean and cotton planted soil was 11.5 and 4.9 times as high as that in its corresponding bare soil. The total respiration, the average soil respiration rate, the total rhizosphere respiration, and the average rhizosphere respiration rate in soybean planted soil were 1.77, 2.34, 2.03, and 2.68 times as high as those in cotton planted soil, respectively. The contribution of rhizosphere respiration to soil respiration during whole growing period was 91.3%, ranging from 3.2% to 95.8% in soybean planted soil, and 79.6%, ranging from 21.8% to 88.0% in cotton planted soil. The exponential correlation between soil respiration rates and air temperatures was significant in growing plants soil, but not in bare soils. The N fertilizer had no significant effect on bare soil respiration. In summary, in the system of soil-crops, crop types and their growing stages are the main factors affected soil respiration, rhizosphere respiration is the main component of soil respiration, and by reason of symbiotic nitrogen fixation, soil respiration and the contribution of rhizosphere respiration were significantly higher in growing soybean soil than in growing cotton soil.
出处
《作物学报》
CAS
CSCD
北大核心
2010年第9期1559-1567,共9页
Acta Agronomica Sinica
基金
中国科学院土壤研究所土壤与农业可持续发展国家重点实验室开放基金项目资助
关键词
大豆
棉花
土壤呼吸
根际呼吸
生长时期
Soybean
Cotton
Soil respiration
Rhizosphere respiration
Growing stages
