Effects of Nitrogen Application on Agronomic Traits and Yield of Rapeseed in No-tillage Rice Stubble Field Effects of Water Table on Rapeseed(Brassica. napus L.) Growth and Yield Relationship between Seedling Traits and Yield Loss of Rapeseed Direct-Seeded in No-Tillage Rice Stubble Field Effects of Waterlogging Time on Rapeseed (Brassica napus L.) Growth and Yield