Assessment of Seasonal Variability of Belowground Biomass in Belgian Grasslands Influenced by Management Treatments

1 Agrobioinstitute, BG - 1164 Sofia, Bulgaria
2 Dept. of Crop Husbandry and Ecophysiology, Agricultural Research Center, Burg. Van Gansberghelaan 109, B - 9820, Belgium


IANTCHEVA, A., I. MESTDAGH, P. LOOTENS and L. CARLIER, 2004. Assessment of seasonal variability of belowground biomass in Belgian grasslands influenced by management treatments. Bulg. J. Agric. Sci., 10: 15 - 23

Seasonal variability of belowground biomass production in different grassland ecosystems in Northern Belgium was estimated by wet sieving of the roots from the soil. Soil core probes were taken from experimental grassland stands, verges (roadside vegetation) and pastures (established in two different years) during three different seasons - autumn (October), spring (May) and summer (July). Influence of the growing season and different management treatments (mowing regimes, fertilization with different N input levels, removal and no removal of the hay, age of grasslands - pasture from 1996 versus pasture from 2000) on root growth was assessed. The highest root growth was established in spring followed by summer and autumn for the studied grassland stands and verges. Root growth dynamics also vary with management treatments. Applying N had no significant effect on belowground production but an intensive mowing frequency (5 mowing per year) led to the highest root biomass production for grassland stands. One mowing per year with removal of the hay was the optimal treatment for verges. Thicker root diameter (> 2 mm) and applied management practice (fertilization with N, one mowing and four intensive grazing periods) for the 1996 pasture and the 2000 pasture led to high and stable belowground production in spring and summer.

Key words: belowground biomass, grassland, management, seasonal variability
Abbreviations: C- carbon, N- nitrogen, d- diameter, CO2 - carbon dioxide