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The summer of 2024 has so far been extremely rainy all over Europe – continuous rain, or regular heavy showers. This presents us with some challenges regarding this year’s hay harvest, as the following applies:
Total drought has its pitfalls, but so does the opposite.

What should you be looking out for now?

The wet weather results in the spread of fungi.
Susceptible grass species, such as tussock grass and tall fescue, start to decay from the stem upwards, while other grasses have leaf fungi.

The leaves of the blades of grass get leaf fungus.
© Sanoanimal
The grass begins to decay from below due to the moisture
The constant wetness from the frequent rain causes the grass to decay from below and the leaves become susceptible to leaf fungus
© Sanoanimal

What does this mean for harvesting hay?

In the short term:

  • The grass should be cut higher so that less of the spoiled, mouldy lower part of the stalks gets into the hay.
  • In some regions, the grass is already lying down due to previous heavy rain showers. In this case, the hay should be cut across the direction of the fall.
  • When buying hay, the hay on offer should always be checked for traces of fungus. Even better to have a microbiological test carried out to be on the safe side.

In the long term:

  • Grass species that are prone to fungal growth should be repressed from the areas and replaced with less susceptible grass species.

When is the right time to start cutting?

The time of cutting determines the nutritional values in the hay – the sugar and fructan content, the digestibility of protein, vitamins, and minerals.

In order to find the right time to cut in the given weather conditions, it is important to determine the main foundation grasses in the area. The maturity of your main grasses should guide your decision.

However, determining the exact time for cutting is a complicated decision:

Should I cut in the morning, when the fructan content is at its lowest (assuming the night was above 8-10 C°), or should I cut in the evening, after an overcast day?

Here are a few basic facts:

  • The grass continues to respire after cutting and thus processes sugar. This respiration process becomes marginal from a water content of 40-50 % and can be neglected.
  • If fawn rescuers are to be integrated with drones in order to avoid injuring fawns, the early morning hours should be used to check the areas with heat-sensitive drones.
    After flying over the areas and securing the fawns, cutting should take place immediately.
  • An old farmer’s saying goes. “It’s better to cut in the rain and drive in when it’s dry than to cut in the dry and drive in when it’s raining.” It is therefore important to correctly estimate the time from cutting to harvesting.
  • Two factors are important for drying: 1. Sunlight, 2. Low humidity.
    So, if you want to make hay successfully, the degree of shading in the sky should be below 50 % and the humidity should also be below 50 % for at least 6 hours, and that for at least the next 3 days.

How much area is to be cut?

Under no circumstances should you cut all day and only turn the following day. If a large area has to be cut and the tractor is also needed for turning, cutting should be carried out until late morning at the latest and then turned over to spread out the grass so that it is fully exposed to the sun. If a second tractor with driver and hay tedder is available, cutting can continue until shortly after midday.

The subsequent turning can then be started in the morning after the dew has dried.

Once the grass has been dried, gathered in rows, and baled, storage begins. High-pressure bales, whether small HD bales or the large, big bales, still have to be brought in on the day of baling.
Due to the high baling pressure of the bales, the hay becomes hygroscopic, i.e. the bales draw water into their core. Even a slight dew can reduce the quality.
With round bales, the baling pressure is lower, so that round bales can be left overnight in dry weather if you run out of time to barn store.

Good luck with the hay harvest or when buying hay.

Helmut Muß
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