On-farm trials in DK highlight plant teams resilience

Here in Denmark, we had the pleasure of having 3 participatory farmers hosting trails with plant teams of cereal legumes, and despite a very extreme drought, the trails did well. Partly, we were lucky with the fields chosen for trails, as two of them could be irrigated and one was on very fertile clay soil with high water capacity, however, the success of the trials also supports that plant teams can offer resilience to extreme weather conditions.

We will explore one of these trials in more detail below. Due to the drought, the field on this farm was irrigated very frequently (8 times in total). This is 5-6 times more than normal. The farmer was aiming to grow a crop of faba beans for his dairy cows and use a cereal companion to provide weed suppression in particular. The faba beans are included as the main protein share in the winter feed for the cows.

What did we learn from this year’s trials?

Firstly, the farmer has found an easy and efficient way to handle the sowing of two crops at once, which must be sown in different depths to grow optimally. The farmer had an old combination sowing machine, which also had tynes for fertilizer placement and the plant team was established with this kit. The cereal grain came in the regular seed box and was sown with the regular sowing tynes at 4 cm depth, while the faba beans came into the container for fertilizer, and were sown via extra strong seed teeth at the desired depth of 8 cm.

The seed rate and seed depth thus became very easy to control for the individual species, and the field was established very successfully with good establishment and a more controlled relationship between the grain and the faba beans. The picture below shows the seed drill’s cutter and the fine field. Faba beans were drilled 25 cm apart with the front sowing tynes. Triticale was drilled with the back sowing tynes – 25 cm apart (12.5 cm from the row with faba beans).

Key result: Very good sowing, with a fast and even germination of the seeds, of both crops in the plant team.

In addition to testing a good sowing method, this farmer also tested which bean-to-grain ratio gave the best weed coverage and ultimately yield in the field. We are an organic organisation and good weed coverage (and high yield) are very important when cultivating the field organically. The results from weed suppression and yield monitoring showed that the higher the proportion of faba beans that were sown, there was better weed coverage and yield (t/ha – see graph below). However, it was evident that weed cover was highest in the monoculture of faba beans and that the triticale helped to keep the weeds down, thus ensuring a high yield in the organic crop. At the same time it is important to get the seed rate of the target crop (faba bean) at the correct level. Due to the drought and heat at germination, the triticale did not establish as expected, and thus we saw less triticale in the plant team than we expected. The triciticale therefore did not compensate for the beans when beans were drilled at a lower seed rate.

Key result: Seed rates are a key determinant of mono and inter crop yields, but adding a cereal companion competed with the weeds and led to an increase in overall yield.

Conclusion
In this special growing season with heavy drought, efficient irrigation, good establishment and the use of plant teams resulted in the best yield in terms of volume for the farmer. This led to an economic benefit despite the heavy use of irrigation as the cost per. kg. of crude protein produced was low. This is of great importance to organic farmers such as the one hosting this trial as purchasing supplementary protein is expensive.

| AUTHOR: Jesper Fog-Petersen |