Allelopathy of Cover Crops on the Germination and Initial Development of Euphorbia heterophylla

Cover crop is a important way for weed management in agriculture. The objective of this study was to investigate the effects of aqueous extracts of the aerial part of Avena strigosa, Cichorium intybus, Chenopodium quinoa and Fagopyrum esculentum in different concentrations on the germination and development of Euphorbia heterophylla. The experimental design was completely randomized, in factorial 4 × 5 with four replicates. Factor A-aqueous extracts of the aerial part of the cover plants and factor B-concentrations of 0%; 1%, 2.5%, 5% and 10%. A total of 25 E. heterophylla seeds, arranged in gerboxes, were used and 15 ml of the extracts were added according to the treatments. The germination test was performed in a growth chamber (BOD) with photoperiod of 12/12 light/dark hours and constant temperature of 25±1 °C. The data were submitted to analysis of variance by the F test, a comparison was made between means and the concentration factor of the extracts and the regression analysis. The C. quinoa aqueous extracts (10%) presented greater allelopathic potential than the other extracts in the variables tested for E. heterophylla. C. intybus presented allelophatic potential with results superior to A. strigosa and F. esculentum. The C. quinoa and C. intybus extracts have allelopathic potential when compared to the control with the highest dose (10%), interfering mainly in the root portion of E. heterophylla.