Phyllochron and Growth Dynamic of Lolium perenne L. and Bromus valdivianus Phil. as Affected by Soil pH, Phosphorus and Nitrogen Restriction

Phyllochron and Growth Dynamic of Lolium perenne L. and Bromus valdivianus Phil. as Affected by Soil pH, Phosphorus and Nitrogen Restriction

Permanent grasslands are the main food for livestock production systems in Southern Chile. Therefore, it is essential to develop management tools that optimize the use of pastures. Among these tools, the phyllochron could be a better method to control grazing frequency. The aim of this study was to determine the effect of three levels of soil pH, phosphorus (P) and nitrogen (N) on the phyllochron and growth dynamic of Lolium perenne and Bromus valdivianus. Nine monophytic mini-swards of each species were established in 125 L containers for three different pH, P and N levels. For one year we measured: phyllochron, total leaf length, leaf expansion rate, sheath length, leaf lifespan, number of leaves per tiller, leaf area, radiation interception, biomass production and nutritive value. For each factor, a complete randomized block design with three blocks and a factorial arrangement of two pasture species and three levels was used. Results showed that soil pH, P and N level did not affect the phyllochron on both species, but significantly modified the growth dynamic and nutritive value of them. The non-limited treatment had the highest leaf elongation rate and size, sheath length, leaf area and biomass production. The radiation intercepted was positively correlated to the leaf area, being the highest at the non-limited treatment. The number of leaves per tiller and the leaf lifespan were not modified, since these characteristics are specific to each species.