Studies On Soil Seed Bank Dynamics Of Digitaria Sanguinalis And Amaranthus Retroflexus In Maize Cropland In North China Plain

This study was completed in Beijing Academy of Agriculture and Forestry Sciences, including 5 parts: the effect of soil temperature, soil moisture, and seed burial depth on the emergence of common crabgrass and redroot pigweed, the analysis of the relativity between productivity and above-ground dry weight of common crabgrass, the research and analysis of weed seed bank dynamics of common crabgrass and redroot pigweed in maize cropland in north China plain, and the model of weed seed bank dynamics.The study was conducted under controlled environmental conditions to determine the effect of soil temperature, soil moisture, and depth of seed burial on the emergence of common crabgrass. Emergence occurred from 15 to 40℃ but was optimal at 20 to 30℃. Common crabgrass emergence was optimal in moist soil with gravimetric water contents of 60%. No germination was observed in warm (40℃) and dry (20%) soils. Emergence percentage decreased as water contents decreased, no matter the soil temperature increased or decreased. A logistic equation described emergence of common crabgrass at each combination of temperature and soil water contents at which emergence occurred. Emergence was greatest at soil depths of 2 to 3cm.The linearity is fitted to describe the relativity between productivity and above-ground dry weight of common crabgrass and redroot pigweed. There are distinct differences in weed seed banks between tillage and no-tillage croplands. The weed seed bank in autumn is bigger than in summer, but it was varied in different year and tillage system. There are no distinct difference in species of weed seed bank between tillage cropland and no-tillage cropland.