High moisture acid sulphate soil effects on reed canary grass
Avainsanat:
reed canary grass, acid sulphate soils, bioenergy, biomass, element compositionAbstrakti
To examine the suitability of acid sulphate soils for perennial energy cropping and specifically to provide information on the responses of reed canary grass (Phalaris arundinacea L.) to raised water levels, a management option for these problematic soils, large core lysimeters of undisturbed field acid sulphate soil were taken into PVC tubes equipped with ground water level control and measurement instruments, planted with reed canary grass, and studied during the period 2008 - 2011. Two treatments; high water content (HWC, 20 cm below soil surface) and low water content (LWC, 70 cm below soil surface, considered normal for acid sulphate soils) were considered and there were 4 replicates. Tiller height, net photosynthesis, and above ground biomass at harvest were measured and Al, Fe, K, Si and S were analysed using ICP-OES. Tillers in HWC lysimeters were 30 and 23% taller than those in LWC lysimeters (P = 0.003, P = 0.002) in September 2009 and 2010 respectively. Net photosynthesis was higher in LWC grasses, although the margin was significant only in year 2009 (P = 0.04). Spring 2009, dry matter yields were almost the same in both treatments, but in 2010 and 2011, HWC grasses yielded 43% and 37 % more than LWC (P = 0.001 in both years), respectively. Dry matter harvested in spring of both 2010 and 2011 contained more Al, K, S and Si in the LWC treatment than in HWC treatment, whereas the concentration of Fe was higher in HWC treatment in 2009 and 2010. It was concluded that reed canary grass, an established bioenergy crop, grows well in acid sulphate soils and can perform better when the water table is raised to reduce acidity and prevent environmental hazards. This could serve as management option and a solution to the problems cause by acid sulphate soils and same time reduce the controversy about the use of bioenergy crops on arable land.
