Crescimento do pinhão-manso em competição com plantas daninhas em dois tipos de solo

Abstract

We aimed with this study to evaluate the effect of six weed species grown in competition with plants of jatropha (Jatropha curcas L.) in Red Yelow Oxisol (LVA) and Quartizarenic Neossol (NQ). The experiment was installed in randomized blocks design with four replications. The treatments were arranged in a 2x6 factorial design, with the first factor represented by two soil types (LVA and NQ) and six weed species (Ageratum conyzoides L., Bidens pilosa L., Cenchrus echinatus L., Commelina benghalensis L., Emilia fosbergii N.) grown along with the crop, plus a control with no competition. Presence of weeds negatively affected growth of jatropha both in LVA and NQ. Among the studied species, C. echinatus and E. fosbergii promoted greater negative effect on jatropha, for most of the variables tested. J. curcas showed better tolerance to reductions in shoot dry matter accumulation when in competition under LVA, a situation contrary to the root system when this oil crop was grown in NQ.soil The growth of jatropha is affected by competition with weeds, but the magnitude of this effect is dependent on the weed species and type of soi