巨型塑料大棚内CO2浓度的变化分析

为探讨巨型塑料大棚CO2环境特征,测试了早春栽培黄瓜不同时期和不同位置棚内CO2浓度的变化,对棚内CO2浓度变化随群体叶面积指数、光合速率和土壤呼吸速率的关系进行了分析。结果表明：一日中棚内CO2浓度在7：00-8：00达最高,12：00-14：00处于低谷,晴天较阴天变化剧烈。结果期一日中的8：00-15：00,光合消耗CO2速率＆gt;土壤呼吸释放CO2速率,通风可维持棚内CO2浓度在293-330μL·L^-1;棚内CO2浓度垂直分布表现为近地面层〉植株内部〉冠层,水平分布表现为10：00-12：00东部〈中部〈西部,14：00-16：00东部〉西部〉中部;棚内CO2浓度的季节变化主要受黄瓜群体叶面积指数、光合消耗CO2速率和土壤呼吸释放CO2速率的影响,晴天棚内CO2浓度白天平均下降速率与LAI（x）的关系为y=78.468x＋48.694,阴天为y=54.358x＋18.322。

Analysis on CO2 Concentration Changes in Super-span Plastic Covered Tunnel Greenhouse

To reveal CO_2 environmental characteristic in super-span plastic covered tunnel greenhouse, the temporal and spatial variation of CO_2 concentration in the greenhouse with cucumber was tested and the relationship between CO_2 concentration and leaf area index (LAI) , photosynthesis rates and soil respiration rates was analyzed. The results showed that CO_2 concentration reached maximum level during 7 :00 -8 :00 and decreased to minimum during 12:00 -14:00 in one day. The variation of CO_2 concentration was wider in sunny day comparing with that in cloudy day. Photosynthesis consumption CO_2 rates was higher than soil respiration release CO_2rates during 8 :00 - 15 :00 at fruit stage, and CO_2 concentration was kept at 293 ～330μL·L~(-1) level by ventilation. The vertical distribution of CO_2 concentration was the ground > the middle > the canopy. The horizontal distribution was the east < the middle < the west during 10:00 - 12:00, and the east > the middle > the west during 14:00 - 16:00. The seasonal change of CO_2 concentrations were affected by LAI, canopy photosynthesis rates and soil respiration rates. The linear regression equation between average decreasing rates of CO_2 concentration and LAI was y =78.468x +48.694 in sunny day and y =54. 358x + 18. 322 in cloudy day.