RYEGRASS AND WHITE CLOVER COMPETITION UNDER A LOW SOIL NITROGEN SUPPLY

Abstract

With the objective to evaluate the competition between perennial ryegrass and white clover under low soil nitrogen supply a glasshouse experiment was conducted. The soil sampled from Valdivia soil series was initially lowered in its nitrogen content by extraction with oat by several months. After extraction, the soil was put in boxes in a completely randomized design with four replicates for treatment. The treatments were: no competition, shoot competition only, root competition only and shoot and root competition. Additionally, two treatments with N fertilization (equivalent to 300 kg N ha_-1) were included: no competition and total competition. The treatments were evaluated during five cuttings and the following parameters were measured: dry matter yield and cutting height of perennial ryegrass and dry matter yield and stolons length on white clover The study allowed to establish that N affect perennial ryegrass competitive ability and it does not affect white clover competitive ability. Moreover, white clover in conditions of a low supply is capable to depress the perennial ryegrass dry matter yield and height because of its higher competitive ability just after cutting. It is suggested that is possible to maintain an adequate balance between perennial ryegrass and white clover when the soil N supply is low if cutting is properly managed.