Biomass production and partitioning of Desmodium incanum in response to phosphate application

Abstract

This work had the objective of analysing the effect of soil type and phosphate (P) levels on production and biomass partition of Desmodium incanum DC. Four evaluations aiming at determining the evolution of total biomass and root and shoot biomass partition were made during the period. The treatments were two types of soil (Plinthaquult and Hapludox) and four levels of phosphate (0, 30, 60, 90 mg of P₂O₅/kg of soil) arranged in a completely randomized design, with four replications. The total N and P content was determined in the dry matter. In the absence of P fertilization both soils had a similar potential for dry matter production. When fertilized, the Hapludox was superior to the Plinthaquult. P deficiency and lower soil natural fertility altered biomass partition. The allocation of assimilates to plant aerial parts was smaller, favoring root growth. Models for P and N dilution were tested, and parameter values for individual plants were proposed.