Effect of Pursley (Richardia scabra L.) on Growth, Nitrogen Uptake an dYield Loss in roselle (Hibsicus sabdariffa var. altissima)

Abstract

Densities of 50 to 200 pursley plants/m of row were established in roselle to quantify roselle yield loss from pursley competition and to approximate economic threshold levels. the linear model y = a + b x + 1 best described reselle yield loss as a function of weed density when pursley emerged within 2 weeks after roselle sowing. Densities of 50, 100 and 200 pursley plants/m of row reduced yield of roselle by 42-58%. shoot dry matter and nitrogen concentration in the shoot of roselle declined by 50 and 33%, respectively after competition with pursley for 30-50 days. Roselle yield was not reduced when pursley cmerged 35 days later than rosselle.