Competitive Ability Effects of Datura stramonium L. and Xanthium strumarium L. on the Development of Maize (Zea mays) Seeds

The objective of this study was to explore the physical properties of maize seeds in competition with weeds. The basic and complex geometric characteristics of seeds from maize plants, competing with Datura stramonium L. (DS) or Xanthium strumarium (XS) at different weed densities, were studied. It was found that the basic and complex geometric characteristics of maize seeds, such as dimension, aspect ratio, equivalent diameter, sphericity, surface area and volume, were significantly affected by weed competition. The increase in weed density from 0 to 8 plants m(2) resulted in an increase in the angle of repose from 27° to 29°, while increasing weed density from 8 to 16 plants m(2) caused a diminution of the angle of repose down to 28°. Increasing the density of XS and DS to 16 plants m(2) caused a reduction in the maximum 1000 seed weight of maize by 40.3% and 37.4%, respectively. These weed side effects must be considered in the design of industrial equipment for seed cleaning, grading and separation. To our knowledge, this is the first study to consider the effects of weed competition on maize traits, which are important in industrial processing such as seed aeration, sifting and drying.