Reduction of incidence of weeds in maize through the use of cover species

This study aimed to evaluate the effectiveness of different cover crops in suppressing weed emergence and their influence on maize productivity under field conditions in Concepción, Paraguay (23°25'40.3"S, 57°20'00.2"W) from October 2021 to June 2022. A completely randomized design was employed with four treatments and seven replications. The treatments consisted of using cover crop species, which were planted in the research area subsequently used to cultivate maize. The cover crops used were Urochloa ruziziensis cv. ruziziensis, Stizolobium pruriens , a mixture ( Urochloa ruziziensis cv. ruziziensis + Stizolobium pruriens ) and a conventional system. The experiment consisted of two stages: first, the installation of the cover crop species, followed by the planting of the maize. Ninety days after planting the cover crop species, the cover crop plants were cut down. Thirty days later, Triple pro DKB360 hybrid maize was sown. The parameters evaluated in the first stage were green weed mass, dry weed mass, green crop mass, and dry crop mass at 90 days after sowing (DAS). In the second stage, the parameters evaluated were green mass of weeds at 20, 35, 50 and 65 DAS; weed suppression at 20, 35, 50 and 65 DAS; cover persistence at 0, 20, 35, 50 and 65 DAS; plant height at 35 and 110 DAS; number of grain rows per ear; number of grains per row; and yield. Variance analysis was carried out on the data using the F-test at 5%, and Tukey’s test at 5% was used to compare the means of the treatments. The mixture of U. ruziziensis and S. pruriens significantly reduced weed biomass by 43.2% compared to the conventional system and showed the highest weed suppression and cover persistence up to 65 days after sowing. Moreover, this mixture produced the highest maize yield (8.42 Mg ha -1 ), representing a 39.4% increase over the conventional system. Treatments with U. ruziziensis alone also outperformed the control, while S. pruriens alone had limited effectiveness. These results highlight the potential of using mixed cover species as a sustainable weed management strategy that enhances maize productivity in smallholder systems.