Trees modify the dynamics of soil CO2 efflux in coffee agroforestry systems1

Published Date
15 August 2016, Vol.224:30–39, doi:10.1016/j.agrformet.2016.05.001

Author 

Gomes Lucas de Carvalho ^a,,,

Cardoso Irene Maria ^a

Mendonça Eduardo de Sá ^b

Fernandes Raphael Bragança Alves ^a

Lopes Vanessa Schiavon ^a

Oliveira Teógenes Sena ^a

• aDepartment of Soil Science, Federal University of Viçosa, Viçosa, 36570-000 Minas Gerais, Brazil
• bDepartment of Plant Production, Federal University of Espirito Santo, Alegre, 29500-000 Espírito Santo, Brazil

Received 7 August 2015. Revised 18 March 2016. Accepted 4 May 2016. Available online 8 May 2016.

Highlights

.   Soil CO₂ efflux dynamics were analysed in agroforestry and full-sun coffee systems.

• •
  Trees reduced soil temperature and maintained soil moisture in agroforestry systems.
• •
  Trees stabilize microclimate conditions and then decrease soil CO₂ efflux variability.
• •
  Soil temperature is the main driver of soil CO₂ efflux in full-sun systems.

Abstract

Agroforestry systems may help significantly reduce atmospheric carbon levels in forthcoming years through photosynthesis and regulation of soil CO₂ efflux. This study aimed to characterise the soil CO₂ efflux dynamics of coffee plants cultivated under agroforestry and full-sun production systems and identify the factors that regulate this process. The study was carried out in agroforestry and full-sun coffee systems on three family farms in Minas Gerais, the Atlantic Forest Biome, Brazil during three consective days on each farm. Twenty 1-m² sampling areas (10 for each system), each separated by a distance of 5 × 5 m and located between coffee plant rows, were selected on each farm. Soil physical and chemical attributes, air temperature and humidity, soil temperature and moisture, the percentage of canopy cover, and soil CO₂ efflux were measured at each sampling area in the two systems. The air and soil temperature in the agroforestry systems were lower and soil moisture was higher than in the full-sun systems. Soil CO₂ efflux showed different dynamics in the two systems. Daytime soil CO₂ efflux was more stable (i.e. from morning to midday) in the agroforestry system (average 15% increase) compared to the full-sun system (average 49.1% increase). Soil CO₂ efflux was regulated by labile carbon and total nitrogen variation in the agroforestry systems, and by soil temperature variation at a depth of 10 cm in the full-sun systems. A principal components analysis with data from all grouped systems showed that soil CO₂ efflux was generally positively correlated with soil temperature at 5 and 10 cm depths, and negatively correlated with soil moisture. In conclusion, agroforestry systems promote microclimate stability and decrease soil CO₂ efflux variability compared to full-sun systems.

Keywords

Climate change

Soil carbon

Soil CO₂ efflux

Tree canopy

Atlantic rainforest biome

 Table 1

Table 1.

 Table 2

Table 2.

 Table 3

Table 3.

Fig. 1.

Fig. 2.

 Table 4

Table 4.

 Table 5

Table 5.

Fig. 3.

 Table 6

Table 6.

Fig. 4.

• ⁎ 
  Corresponding author at: Universidade Federal de Viçosa, Departamento de Solos, Av. Peter Henry Rolfs SN, Centro, Viçosa, CEP 36570-000 Minas Gerais, Brazil.
  
  

For further details log on website :

• http://www.sciencedirect.com/science/article/pii/S0048969701008993