This research consisted with a pot experiment and a field experiment.The effects of different straw-returning methods and straw-returning rates on emergence speed and emergence percentage of rapeseed were studied by the pot experiment,while the growth, nutrients absorption and yield of rapeseed and the condition of soil temperature and moisture under different straw-mulching rates were studied by the field experiment.The results of the pot experiment showed that both mulching straw and ploughing straw under...