CONTRIBUTION OF SOIL RESPIRATION TO THE CARBON BALANCE OF AN APPLE ORCHARD
Soil respiration was recorded in an apple orchard near Bonn, Germany, over 2 years (1995–96) with a portable, battery-driven infrared gas analyzer and a soil respiration chamber (soil respiration system 'SRS' from PP Systems, Hitchin, UK) to examine the contribution of soil respiration to the CO2 balance of a fruit orchard and to study the effects of heat, frost, herbicide, drought and rainfall:
- In the summer, maximum soil respiration of 27 μmol CO2 m-2 s-1 was at a temperature of 37°C. A further increase in temperature reduced soil respiration.
- Simulated rainfall of 30 mm after a prolonged dry spell increased soil respiration from an average of 5 to 7 μmol CO2 m-2 s-1 on a warm autumn day in October.
- Freezing and thawing processes in January released organic carbon which induced respiration rates of 1.2–2.2 μmol CO2 m-2 s-1.
- Soil respiration rates of 1–3 μmol CO2 (winter), 3–8 μmol CO2 (spring/autumn) and 9–18 μmol CO2 m-2 s-1 (summer), based on alleys comprising 33% of orchard acreage and equivalent to 0.5–1.4 kg (winter), 1.4–3.8 kg (spring/autumn) and 4.3–8.6 kg (summer) CO2 ha-1 h-1 exceeded root and tree respiration, contributed significantly to the CO2 flux in a fruit orchard, and may be a pertinent source of CO2 for tree photosynthesis. More research is needed for different soil types and planting systems over a wide range of environmental conditions.
Blanke, M. M. (1997). CONTRIBUTION OF SOIL RESPIRATION TO THE CARBON BALANCE OF AN APPLE ORCHARD. Acta Hortic. 451, 337-344
apple, Malus domestica Borkh., bioenergetics, biometerology, CO2, environment, greenhouse effect, micro-climate