Effect of night cultivation on the emergence and competition of weeds in buckwheat

The objective of this research project was to identify the effect of night cultivation as a weed management practice to reduce weed populations and their competitive effects within a cropping system. The type of cultivation method used and the degree of soil inversion has been found to alter the number of seeds that are triggered to germinate by a brief exposure to light. For this reason, the project also compared disc tillage and zero tillage systems on potential weed seedling emergence. Buckwheat ('Fagopyrum esculentum' Moench) was chosen as the crop in which to test these effects. The results of the research indicated the potential for short-term reductions in weed seedling emergence when light is excluded during the process of cultivation and sowing. For example, there was a significant reduction in the number of bladder ketmia ('Hibiscus trionum' L.) and amaranth ('Amaranthus' sp.) seedlings that emerged within 24 days following night soil cultivation and sowing. However, this difference was not observed when measured 37 DAS and later. Disc tillage had significantly higher weed densities and biomasses throughout the experiment than the zero-tillage treatments. The buckwheat crop also suppressed weed populations, such that weeding the crop did not increase yield. These results suggest that night cultivation may yet prove beneficial in an integrated weed management system.