Potatoes in intensive root crop rotations. Effects of previous crop, green manure, organic fertiliser and soil cultivation.

摘要

A crop rotation field experiment was established in 2001 at Goch-Pfalzdorf in the Lower Rhine region of western Germany. Eleven different rotations, either 3-year, 4-year or 5-year long were compared. The main crop sequence was: silage maize - winter wheat - potatoes. Oil-radish was used as green manure crop, after winter wheat and organic fertilisers were straw, FYM or slurry. Results showed a positive effect of the green manure crop with 5.3 t/ha higher potato yields. Green manure and straw fertiliser added another 1.5 t/ha, FYM 3.7 t/ha while straw and slurry only added 0.1 t/ha. Oil-radish and fertiliser treatment had on average also an effect on the subsequent yields of maize (0.4 t/ha more) and winter wheat crops (0.2 t/ha more), two years after the green manure crop was grown. Changing the rotation to winter wheat - silage maize - potatoes reduced the yield of potato (2.5 t/ha less) and silage maize (2.1 t/ha less). Effects of different treatments using cultivation ploughing and minimal tillage or autumn versus spring ploughing, were not found after 8 years and may need more time to show differences, if any [no statistics given, demonstration trial].