Crop yield in Swedish experiments with shallow tillage and no-tillage 1983-2012

Crop yield data from 918 experimental years with shallow (5-10 cm) non-inversion tillage and 226 experimental years with no-tillage conducted in the period 1983-2012 were analysed, especially regarding effects of crop, preceding crop, soil type and duration of tillage system. For all experiments with shallow tillage, crop yield was 1.8% lower than for mouldboard ploughing. Yield of spring cereals and spring oilseed rape (Brassica napus L) was similar for the two systems, while yield of peas (Pisum vulgare L.), sugar beet (Beta vulgaris L), potatoes (Solanum tuberosum L) and winter oilseed rape (Brassica napus L.) was 5-10% lower for shallow tillage. Winter wheat (Triticum aestivum L) yield in particular was much affected by preceding crop, with lower relative yield for shallow tillage with cereal as the preceding crop. For no-tillage, relative yield was on average 9.8% lower than for mouldboard ploughing, with the greatest yield losses for spring-sown crops. Plant establishment was similar for shallow tillage and mouldboard ploughing, but lower with no-tillage. There was no obvious trend in crop yield over time in long-term experiments with shallow tillage, indicating that in terms of crop yield, primary tillage systems can be chosen depending on the conditions in a specific year. The results indicate that compaction in reduced tillage under Swedish conditions was a minor problem for cereals, whereas dicots were more sensitive to compaction. The major problems in reduced tillage were caused by plant residues and, in no-tillage, by poor establishment due to the lack of a seedbed. Overall, the results show that under Swedish climate conditions, shallow tillage can give similar yields to mouldboard ploughing. For no-tillage, the system has to be improved to secure plant establishment and crop yield. (C) 2013 Published by Elsevier B.V.