摘要
陆地土壤呼吸是碳从土壤进入大气的主要途径,与全球变化密切相关。土壤呼吸具有明显的季节和日变化动态,其季节动态与温度变化特征密切相关,还与各个地区降水量的变化趋势有关,一年中一般在7～8月份达到最高值,以后逐渐下降,从11月～翌年4月份最低且相对稳定。土壤呼吸的日变化与温度尤其是表层5～20cm地温的日变化相一致,表现为上午明显高于下午,而在早晨和傍晚时较低。不同生态系统的土壤呼吸作用存在很大的差别。一般地,森林土壤>农田土壤>草地。影响土壤呼吸的因素很多,除了土壤的通透性等物理特性和土壤微生物特征外,气温、土温、湿度、大气CO2浓度、土壤无机养分和有机质的含量与组成等都会影响土壤呼吸。大多数情况下,土壤呼吸速率是土壤一定深度地温或土壤含水量的函数。土壤呼吸随CO2浓度的升高而加强。施有机肥、N沉降和灌溉通常会使土壤呼吸增强;而施加矿质肥对土壤呼吸的影响不明显。
Soil respiration of terrestrial ecosystems is a main way of carbon dioxide flue from soil to atmosphere and thus is connected with global change. Soil respiration has great variation in space and time.Its remarkable diurnal and seasonal dynamic are changes observed. Soil respiration is consistent with the trend of temperature and precipitation. It generally reaches the peak of a year at July or August and then declines gradually to nadir during November the next April. CO_2 emission is higher in the morning than in the afternoon and usually reaches maximum between 12:00 and 14:00. This trend accords with temperature of soil especially soil of 5 to 20 cm.Soil respiration of different ecosystems differs from each other. Forest soil generally has the highest value and grassland the lowest with cropfield in between. Besides the capacity of aerates, pH and microbial activity, soil respiration is also affected by soil temperature, humidity, concentration of CO_2 in atmosphere, nitrogen deposition and factors man-made. In general, soil respiration is a function of soil temperature and water content. With the raise of concentration of CO_2 in atmosphere soil respiration accelerates.
出处
《江西农业大学学报》
CAS
CSCD
2004年第1期138-143,共6页
Acta Agriculturae Universitatis Jiangxiensis
基金
国家自然科学基金项目(30170191)
广东省自然科学基金项目(20000976
003031)
