Effect of intercropping and mulching on weed composition in agroclimatic zones of Zimbabwe

Weed species composition is significantly affected by crop management practices. Intensive cropping is often associated with a reduction in weed species diversity. This study was conducted to assess the effect of intercropping and mulching on weed flora in three agroecological regions in eastern Zimbabwe. Two replicated on-farm trials were laid out in three agroecological regions. Treatments included sole maize, sole maize with 4 or 8 Mg ha−1 mulch, sole cowpea, maize + cowpea intercrop and maize + cowpea intercrop with 4 or 8 Mg ha−1 mulch. Maize stover was used as mulch. Different weeds were identified and sampled at five positions within plots using 0.5 m × 0.5 m quadrats. Among the 34 weed species identified across sites, Richardia scabra and Cynodon dactylon were the most dominant weed species and were mostly associated with sole maize cropping. Maize stover as mulch contributed to a reduction in weed species density. Maize + cowpea intercropping systems proved effective particularly in suppressing the prevalence of R. scabra and C. dactylon. Cowpea grown as a sole crop was found to be effective in reducing the infestation of weeds. Maize intercropped with cowpea along with mulching resulted in a significant reduction of weed species, especially in arid agroecological zones.