Abstract:

Farmland ecosystems are emerging as the third largest source of biogenic volatile organic compound (BVOCs) emissions, following forests and grasslands. Focusing on the main crops of the Inner Mongolian Plateau [corn (Zea mays L.), potato (Solanum tuberosum L.), and rice (Oryza sativa L.)], dynamic chamber sampling combined with ATD-GC/MS technology was employed to determine their BVOCs emission characteristics. By coupling parameters such as temperature and photosynthetically active radiation (PAR) using the G93 and G95 models, the emission rates under standard conditions (T=303 K, PAR=1000 μmol∙m⁻²∙s⁻¹) were calculated. The results showed that: 1) all three crops emitted 18 volatile organic compounds, including α-pinene, camphene, β−pinene, β−myrcene, α−phellandrene, 3−carene, α−terpinene, p−cymene, limonene, γ−terpinene, terpinolene (monoterpene), isoprene, and benzene, toluene, ethylbenzene, m−xylene, p−xylene, o−xylene (BTEX). 2) the emission rates of isoprene, monoterpene, and BTEX from corn were 15.8‒363, 4.36‒94.5, and 46.9‒706 µg∙g⁻¹∙h⁻¹, respectively; those from potatoes were 4.47‒26.1, 10.3‒149, and 5.76‒78.4 µg∙g⁻¹∙h⁻¹, respectively; and those from rice were 3.69‒12.7, 3.52‒25.8, and 1.70‒15.1 µg∙g⁻¹∙h⁻¹, respectively. 3) The emission rates of isoprene, monoterpene, and BTEX from corn under standard conditions were 156, 9.49, and 125 µg∙g⁻¹∙h⁻¹, respectively. For potatoes, the rates were 16.9, 39.6, and 14.1 µg∙g⁻¹∙h⁻¹, respectively. For rice, the corresponding values were 3.66, 4.05, and 3.41 µg∙g⁻¹∙h⁻¹, respectively. The emission rates of BVOCs from major crops on the Inner Mongolian Plateau exhibited significant temperature and PAR dependencies, as well as diurnal variations. This result provides a scientific basis for studying the contribution of BVOC emission rates to regional environmental ozone concentrations on the Inner Mongolian Plateau.

Key words: Inner Mongolia Plateau, crops, biogenic volatile organic compounds (BVOCs), emission rates, dynamic chamber sampling method

摘要：

农田生态系统正成为继森林和草原之后第三大生物源挥发性有机物（Biogenic Volatile Organic Compounds，BVOCs）排放源。以内蒙古高原主要农作物[玉米（Zea mays L.）、马铃薯（Solanum tuberosum L.）和水稻（Oryza sativa L.）]为对象，采用动态箱采样结合ATD-GC/MS技术，测定其BVOCs排放特征，并通过G93与G95模型耦合温度、光合有效辐射（PAR）等参数，计算标准状态（T=303 K，PAR=1000 μmol∙m⁻²∙s⁻¹）下的排放速率，结果表明：1）3种农作物均排放α−蒎烯、崁烯、β−蒎烯、β−月桂烯、α−水芹烯、3−蒈烯、α−萜品烯、对伞花烃、柠檬烯、γ−萜品烯、萜品油烯（单萜烯）、异戊二烯和苯、甲苯、乙基苯、间二甲苯、对二甲苯、邻二甲苯（BTEX）等18种挥发性有机物；2）玉米的异戊二烯、单萜烯和苯系物排放速率分别为15.8-363、4.36-94.5、46.9-706 µg∙g⁻¹∙h⁻¹，马铃薯这3种物质的排放速率分别为4.47-26.1、10.3-149、5.76-78.4 µg∙g⁻¹∙h⁻¹，水稻分别为3.69-12.7、3.52-25.8、1.70-15.1 µg∙g⁻¹∙h⁻¹；3）玉米的异戊二烯、单萜烯和BTEX在标准状态下的排放速率分别为156、9.49、125 µg∙g⁻¹∙h⁻¹，马铃薯这3种物质在标准状态下的排放速率分别为16.9、39.6、14.1 µg∙g⁻¹∙h⁻¹，水稻分别为3.66、4.05、3.41 µg∙g⁻¹∙h⁻¹。内蒙古高原主要农作物BVOCs排放速率呈现明显的温度与PAR依赖性及日变化规律。该结果可为研究内蒙古高原BVOCs排放速率对区域环境臭氧浓度的贡献提供科学依据。

关键词: 内蒙古高原, 农作物, 生物源挥发性有机物（BVOC_S）, 排放速率, 动态箱采样法