| The purpose of this study was to examine the effects of different stubbles on soil fertility and rapeseed yield in the following season. Using traditional field experiment, with fallow field as control, the stubble soil ploughing layer of six main crops (winter rapeseed, potato, corn, winter wheat, spring wheat, and broad bean) in Northwest Loess Area and its effect on the yield and agronomic characters of winter rapeseed in the following season were studied. The result showed that: (1) The overall soil nutrient content of different crop stubbles showed that overwintering crops > fallow fields > spring sown crops. Except the broad bean stubble had a higher alkaline nitrogen content of nitrogen\|fixing, the winter rapeseed stubble had a significant better result than those of other crops in soil nutrient indexes, soil microbial population structure and soil physical properties. Their organic matter, total nitrogen, total phosphorus, total potassium, alkaline nitrogen, fast\|acting phosphorus, and fast\|acting potassium contents were 32.6%, 12.1%, 5.9%, 7.2%, 11.6%, 99.8% and 44.2% higher than the control treatment. Followed by bean, winter wheat stubble and fallow fields, the corn and spring wheat stubbles had a poorer fertility status. Compared with the fallow field, the soil bulk density of tillage layer (0~20 cm) of winter rapeseed, winter wheat and broad bean stubbles decreased by 10.14%, 5.80%, 5.80%, respectively. The total soil porosity, capillary porosity and field water holding capacity of winter rapeseed stubbles increased by 7.33%, 4.12% and 5.65%, respectively, while potato, corn and spring wheat stubble all decreased to different degrees. There was no significant difference between winter wheat and broad bean stubbles. (2) The effects of previous crop on agronomic traits of winter rapeseed were mainly reflected in plant height, root weight, number of whole plant, number of pod and 1000\|grain weight. Among them, the yield of winter rapeseed in broad bean stubble was 4.50% higher than that in fallow field, and the stubble of winter wheat was equivalent and winter wheat stubble was similar to fallow field. The yield of potato, corn, spring wheat and winter rapeseed stubbles decreased by 11.05%, 15.04%, 16.27% and 21.14%, respectively, compared with that of the fallow field. The best preceding crop of winter rapeseed was bean crop. The fallow field and winter wheat crop were also good preceding crops. However, continuous cropping of winter rapeseed could produce autotoxicity or aggravate disease, which would significantly affect the yield, so it is not suitable for continuous cropping. |