Keyline Plowing: Soil Nutrients and Grass Yield 2016

by Mikala Parr, Research Assistant

In 2014 RAIN’s Keyline Plowing Project was initiated to determine whether keyline pattern subsoiling would help with water distribution. The aim was to determine if the keyline technique had an impact on grass yield and the water content of soil throughout the field.

Soil Nutrients

In order to determine if the soil nutrients have been affected due to the keyline plow, samples were taken from both the high point and low point of every pasture involved. In general, the soil nutrients were not affected by plowing. The only significant difference was higher levels of zinc in the low lying areas.  Zinc is held on the surfaces of clay, organic matter, and organic materials, but there did not seem to be a significant difference in the organic matter between high or low sampling sites, therefore the difference in zinc is likely due to natural variability and sample size.

The only way to change nutrients in the soil is to add nutrients or to change the pH. Some advocates for keyline plowing have claimed that it helps increase organic matter, but in this study that did not seem to be the case. Building organic matter is a gradual process that takes many years, and this project may not have had a long enough time span to see that kind of result.

Grass Yield

Grass yield was not significantly different between the keyline plowed treatment and the control. Grass growth is very dependent on the amount of available water in the soil. Keyline plowing is supposed to slow water movement from high to low areas and even out topography effects, but with the drought in 2016 it was difficult to determine if there was a practical benefit from this method of water management.

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Thanks go to our farmer cooperator, Peter Lambert.

More information from this project is summarized here: 2015 Results from the Keyline Plowing Trial

This project was funded in part through Growing Forward 2 (GF2), a federal-provincial- territorial initiative. The Agricultural Adaptation Council assists in the delivery of GF2 in Ontario.