This research was carried out under greenhouse conditions at the College of Agriculture, campus of Jaboticabal, UNESP, with the objective of studying the effects of different levels of phosphoric fertilization (0, 33.5, 67.0 and 100.5 ppm P2O5) and shading levels (0, 30, 50 and 70% of light interception) on some growth parameters of purple nutsedge (Cyperus rotundus). The tubers emerged were placed (in numbers of 4) in plastic pots containing three liters of dark Red Latossoil (soil), medium texture, being previously screened. The experiment was land out in a completely randomized design with four replications. The results showed the detrimental effect of shading on purple nutsedge development; at a level of 30% shading there was a reduction in plant density, mainly due to a reduction in the number of bulds and tubers. As a consequence there was a reduction in the dry matter accumulation in the subterranean parts (bulbs, tubers and roots), causing na increase in the ratios PA/B+T+R and B+T/R. Phosphoric fertilization, however, increased the growth parameters of the species, mainly in the development of the PA by na increase in the number and dry matter accumulation.
Biology