Calcethorpe Updates Late May 2017

The Effects of Cover Crop Termination Timing: Published Late May 2017

The establishment of the spring barley crop has been effected when following the single cereal species cover crops (oats, rye and triticale). This area was drilled into the green. This is a an example of a high C:N ratio and subsequent nitrogen lock up of the following crop.

This was not seen in the mixes and those sprayed off with a 4-6 weeks gap before spring cereal drilling. This is looking the best piece of spring barley at the site so far.

As the photos show, the area where the higher C:N ratio cover crops (Oats, Rye, Triticale) were, there is significantly more trash on the soil surface, which is where the nitrogen is being temporarily locked up. When comparing the GAI (green area index) of the different termination methods, there is also dramatic differences.

They are as follows;

High C:N ration cover crop areas – 0.16 GAI

Low C:N ratio cover crop areas – 0.99 GAI

Mixes sprayed odd 4-6 weeks before drilling – 1.35GAI

The lower C:N ratio plots and the ex-mixes had at least 1 extra tiller per plant in comparison to the high C:N plots. They also had much fewer weeds in them due to increased crop competition.

The Effects of Cover Crop Termination Timing on the Following Crop Establishment

We have performed a soil health survey on the 2 sections of the field (high and low C:N ratio) to see the difference the crop can make in the soil. As you can see from the photos, the crop following the low C:N ratio cover crop has a much more pleasing aggregation to that following a high C:N ratio cover crop. This is purely down to rooting mass differences from the barley crop between the 2 plots in this case.

The soil following the low C:N ratio had also dealt with the recent heavy rainfall much better, this is due to the aggregates being much smaller and therefore the soil having a much larger surface area to absorb the excess moisture. This had also meant less excess rainfall had been lost to the subsoil keeping the soil much more moist and warmer when compared to the soil following the low C:N ratio cover crop.

The Effects of the Growing Crop on the Soil Structure