Below-ground plant production in a perennial grass ley (Festuca pratensis Huds.) assessed with different methods.
Abstract
In a 2nd year F. pratensis ley 5 values for belowground production (BGP) were estimated using 2 field methods: soil coring and ingrowth mesh bags. Soil samples were washed, and ash-corrected DW were determined twice monthly during the growing season. Samples were sorted into living roots and remaining organic material on 4 of the 14 sampling occasions. BGP calculated as the difference between the annual max. and a preceding spring min. varied between 0.19 and 0.27 kg ash-free DW/m2, depending on the fraction (living roots or unsorted soil organic material) used in calculations. The decomposition rate of soil litter (the dead organic material found by washing soil samples collected in spring before start of growth) was estimated and the BGP was corrected using this value while taking into account that measured increases were underestimated due to concomitant root death and decomposition of soil litter. The seasonal BGP ranged between 0.36 and 0.46 kg/m2. The higher estimate was achieved when the increases in living (0.19) and dead roots (1.27) were summed. The production, estimated as the max. amount of roots found in mesh bags, was 0.29 kg/m2. It was concluded that the highest estimate (0.46 kg/m2) was the most accurate estimate of BGP.