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Effects of tillage on flat areas


Research Professor Marianne Bechmann. Photo: Morten Günther.

Today support is given for changed tillage methods, but most research trials are conducted on areas with high erosion risk. Now researchers from NIBIO are examining the effects of tillage on flat areas.

The question is what type of tillage gives least soil loss and least runoff of phosphorus and pesticides. Is it better for the environment to plough in the autumn or in the spring, and what soil loss results from cultivation of autumn crops? The findings could have consequences for current support schemes for tillage.

Most of the agricultural areas in Akershus and Østfold are located in areas without steep slopes. The experiment at Kjelle in Bjørkelangen was started in 2013 in order to shed light on the effect of tillage on areas which are only slightly sloping and with low erosion risk.

The most important conclusion from the experiment’s first years (2014-2015) was that the autumn-ploughed plots had on average three times more soil loss than the spring-ploughed plots.

Phosphorus losses followed the same trend as for soil loss, but with slightly smaller differences between the treatments. The loss of dissolved phosphorus was less dependent on the type of tillage than loss of phosphorus that was bound to particles (particulate phosphorus).

The annual nitrogen losses were lowest from autumn grain and highest from that which was autumn-ploughed. Very high concentrations of nitrogen were determined in the spring water samples in the plots with spring grain, both those which were autumn-ploughed and those which were spring-ploughed.

Growth and uptake of nutrients through the summer has increased the risk for runoff of nitrogen from the autumn grain plots.