No trade-off between root biomass and aboveground production in Lolium perenne

Grasses have dense rooting systems, but nutrient uptake and drought resistance can be increased, and N-leaching reduced, if rooting is further improved. Improved rooting of grasses in agricultural systems should, however, not be a trade-off with aboveground biomass allocation and yield. In two field experiments on sandy soil in the Netherlands, we measured the variation in grass yield of sixteen varieties of Lolium perenne (Lp) during three years, and the root dry matter (RDM) at the end of the experiments. The Lp-varieties differed in aboveground and genetic characteristics such as productivity (classified according to the measured yields in the actual experiments), grass cover and ploidy. Results of the experiments show that RDM of perennial ryegrass differed significantly between varieties, and that these differences were not linked to grass yield. Our results indicate that it is possible to select perennial ryegrass varieties that combine high aboveground productivity with high RDM. Considering challenges in the areas of climate change, pollution and soil degradation, high yielding grass varieties with improved root systems could contribute to an efficient use of nutrients and water, and to erosion control, soil improvement and carbon sequestration.