Drought on your grassland: irrigate or wait?

The grass is yellow, your silage stocks are shrinking and there is no rain in the forecast. Now you have to choose: irrigate or wait. That depends on what you have already done and on how much rain is still to come. It also decides your next cut and your silage stocks.

Should you irrigate dry grassland?

That depends on what you have already done:

• Already irrigating? Then keep going and keep an eye on the weather forecast. Bear in mind that some areas may have an irrigation ban.
• Not irrigated yet? Then don't start if the grass has already turned quite yellow. The effect of irrigating is too small by then. Leave the grass alone so it can recover.

Calculations by Wageningen University & Research (WUR) for the De Marke research farm show that irrigating grass in spring on dry sandy soil gives an average of 24 kg dry matter per mm of water. On grazed fields there was no clear effect.

Is yellow grass dead?

Usually not. In a drought, grass curls up and turns yellow, and it soon looks dead. But the plant is dormant. As long as the growing point is alive, the grass grows back. That only happens once there is enough moisture again.

How much rain is needed before grass grows again?

One or two showers aren't enough. It has to rain properly for several days in a row before the grass recovers and starts growing. The weather stays changeable: the big question is whether it will rain and how much. That is why we outline three scenarios below.

What do you do in a drought? 3 scenarios

Scenario 1: no rain for now

If no rain falls in the coming weeks and a wet spell only arrives in early September, you won't bring in the next cut until late September or early October. The rain may also come too late for your fields. By then autumn is close, and after two weeks of rain the grassland is too wet. You can then forget about the last cut.

What does that mean for you?

• You probably won't have enough silage and will need to buy in extra feed. That depends on your stocks from last year.
• Take a good look at which fields you need to reseed for next season.
• Already irrigating? Then keep going to limit the damage.

Scenario 2: some rain, small showers

If small showers fall, you have to wait and see what effect they have. That depends on the condition of your grassland and the soil type.

• Keep a close eye on the condition of your fields.
• Irrigate extra where needed. That also depends on your feed stocks from last year.
• With small showers, you cut the next crop in about six weeks and the losses stay limited.
• Reseed fields where needed for next season.

Scenario 3: some rain, heavy showers

If it rains properly for several days in a row, the grass gets going again. After that it takes about 3 to 4 weeks before you can cut again.

In this scenario, the damage is limited for many farmers. Hardly anything needs reseeding. Many farmers don't need to buy in feed either, because they still have stocks from last year.

What do you do with the grass you do harvest?

After a dry spell, every cut is valuable. Dry grass is harder to ensile. What dry silage means and how to deal with it is explained in a separate article, as are the 6 tips for good silage compaction. What else decides the quality of your silage is covered in improving silage quality.

After that, you seal the silage properly: this is how covering grass silage works. See how to cover your grass silage airtight with Silage Safe, without tyres, on our product information page. If you also grow maize, see when to irrigate maize.