Influence of straw-returning on rapeseed (Brassica napus L.) growth, soil temperature and moisture

This research consisted of a pot and a field experiment. The effects of different straw-returning methods and straw-returning rates on emergence and growth at seedling stage of rapeseed (Brassica napus L.) were studied using 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 and turnover inhibited the emergence of rapeseed, but the inhibition effect of mulching was more severe. The effect of straw-mulching on growth of rapeseed at seedling stage was very limited, while the effect of turnover was more pronounced. Field experiment results showed that mulching could enhance significantly dry matter accumulation and nutrients absorbed rate of rapeseed at seedling stage, but had no effect from bud period to pod period compared to no straw-mulching treatment (CK). Compared with CK treatment, mulching could increase significantly rapeseed yield by 18.1% on average, while mulching rates had no effect on rapeseed yield. The results of the field experiment also indicated that compared with CK treatment, mulching could increase soil water content significantly, and lower the variation of soil temperature.