I realy like this side wall effect after dts it help to protect crops from the wind in winter and help snow to stay in seed 'trench'They are needed as they do move soil into the furrows left by the back coulters. Bulldozing soil does make bung ups more likely and they are not meant to be a levelling bar, though that would be handy as my fields need levelling. Jeff Claydon advised against 2 rows of harrow tines as an alternative except on really wet going or very light land.