Above- and below-ground interactions between Lotus tenuis and Cynodon dactylon under different fertilization levels

Abstract

Llobet, M., Vignolio, O. R., Savé, R. and Biel, C. 2012. Above- and below-ground interactions between Lotus tenuis and Cynodon dactylon under different fertilization levels. Can. J. Plant Sci. 92: 45–53. Mixtures of legumes and grasses are recommend for xeric garden fields, landscape restorations and to improve productivity, digestibility and quality of grasslands and pastures, due to the complementarity in the use of resources, their resistance to wide edaphoclimatic conditions and the nitrogen-fixing ability of the legume. However, legumes persistence is poor. Two greenhouse studies examined the relative importance of above- and below-ground competition and root physiological attributes between a legume Lotus tenuis and a grass bermudagrass (Cynodon dactylon) under two fertilization levels. The plants were arranged using the ″Divided pot" technique during 34 wk. Root competition was more important on the performance of both species than shoot competition. Cynodon dactylon had greater nutrient use efficiency than L. tenuis. The low root hydraulic resistance and high specific root length of C. dactylon could enhance its ability to explore the soil and compete for water and nutrients more efficiently than L. tenuis, which compensates for these characteristics with a higher root:shoot ratio than C. dactylon. Although mechanisms involved in root competition between species are not fully understood, our results show that root physiological and morphologic traits contribute to understanding the responses of the species in mixture.