西双版纳香蕉园土壤CO_2排放特征

Soil CO_2 Emission from Banana Plantation in Xishuangbanna,Yunnan,Southwest China

香蕉种植园是目前西双版纳地区主要的土地利用类型之一,为探讨常规施肥管理下香蕉种植园土壤CO_2排放特征及其影响因子,选取西双版纳地区典型的坝区香蕉种植园,采用静态箱-气相色谱法开展了为期一年的试验。试验结果表明:(1)旱季日变化观测日为晴天,白天土壤CO_2排放速率高于夜间,雨季观测日下午有降雨,土壤CO_2排放速率夜间高于白天,雨季种植台地土壤CO_2日排放量显著高于旱季(p<0.05),而排水沟土壤CO_2日排放量在旱季和雨季无显著差异;(2)香蕉植株下方、香蕉植株之间和排水沟土壤具有相同的土壤CO_2排放季节变化特征;(3)香蕉种植园土壤CO_2排放表现为雨季高于旱季,年排放总量为9.01±1.45 t C hm-2a-1;(4)香蕉种植园土壤CO_2排放与气温、土温和土壤含水量存在极显著(p<0.01)或显著(p<0.05)正相关性。本研究结果为初步了解中国西双版纳乃至热带地区香蕉种植园土壤CO_2排放现状,为香蕉种植园生态系统碳循环和估算区域CO_2排放量提供基础数据,也可为香蕉种植园可持续利用与管理提供科学依据。

Nowadays banana plantation has been one main type of land use in Xishuangbanna.A one-year study was conducted in a banana plantation in Xishuangbanna to gain the character of CO 2 emission and its influence factors using the static chamber and gas chromatography techniques.The results showed that:(1)The CO 2 flux was higher in day-time than in night in dry season when the observation day was sunny,but we found opposite result in rainy season as the rainfall in the afternoon of this day.The diurnal CO 2 flux in rainy season was significantly(p<0.05)higher than in dry season on the terrace bench,but no difference was observed on the drainage ditch.(2)The seasonal pattern of soil CO 2 emission was the same under different sites(soils under banana plants,between banana plants and on the drainage ditch).(3)For all sites,soil CO 2 emissions were higher in rainy season than in dry season,and the total annual emission was 9.01±1.45 t C hm-2 a-1.(4)The CO 2 flux had significant positive correlations with both air and soil temperature(p<0.01)and soil water content(p<0.05).The results of this study provided a preliminary understanding of CO 2 emissions from soil under banana plantation in tropical regions of China that revealed basic data for the carbon cycling in banana plantation ecosystem and provided a scientific theoretical basis for sustainable management of banana plantations.