Daily and seasonal patterns of CO2 fluxes and evapotranspiration in maize-grass intercropping

Revista Brasileira de Engenharia Agrícola e Ambiental

Souza, Rodolfo M. S.³  Lima, José R. de S.¹  Souza, Eduardo S. de²  Antonino, Antonio C. D.³  Alves, Edevaldo M.⁴  Machado, Cássia B.³ 

[1] Universidade Federal Rural de Pernambuco, Garanhuns, Brazil;Universidade Federal Rural de Pernambuco, Serra Talhada, Brazil;Universidade Federal de Pernambuco, Recife, Brazil;Universidade Federal de Pernambuco, Caruaru, Brazil

关键词: eddy covariance;    carbon;    climate change;   

DOI  :  10.1590/1807-1929/agriambi.v20n9p777-782

学科分类：农业科学（综合）

来源: Universidade Federal de Campina Grande * Centro de Ciencias e Tecnologia

【 摘 要 】

Studies that investigate the relationships between CO2 fluxes and evapotranspiration (ET) are important for predicting how agricultural ecosystems will respond to climate changes. However, none was made on the maize-grass intercropping system in Brazil. The aim of this study was to determine the ET and CO2 fluxes in a signal grass pasture intercropped with maize, in São João, Pernambuco, Brazil, in a drought year. Furthermore, the soil water storage (SWS) and leaf area index (LAI) were determined. The latent heat flux was the main consumer of the available energy and the daily and seasonal ET and CO2 variations were mainly controlled by rainfall, through the changes in soil water content and consequently in SWS. The agroecosystem acted as an atmospheric carbon source, during drier periods and lower LAI, and as an atmospheric carbon sink, during wetter periods and higher LAI values. In a dry year, the intercropping sequestered 2.9 t C ha-1, which was equivalent to 8.0 kg C ha-1 d-1. This study showed strong seasonal fluctuations in maize-grass intercropping CO2 fluxes, due to seasonality of rainfall, and that this agroecosystem is vulnerable to low SWS, with significant reduction in CO2 uptake during these periods.

【 授权许可】

Unknown