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Dry grass? Leave it alone, it will recover by itself

Gepubliceerd op
24 juli 2018

Dutch grasslands threaten to dry up since it has not rained for too long. What should farmers do? Bert Philipsen, Animal Nutrition expert at Wageningen Livestock Research, advises to leave the grass alone. It can recover well when not destroyed.

In case of drought, plants limit their evaporation: trees drop their leaves and grass curls and yellows. However, it is not dead, but at rest, like hibernating. 'If the growth point stays alive, the grass will recover,' says Bert Philipsen. ‘As soon as moisture comes in it starts to grow again.’ But in the meantime, dry grass can be better left untouched. 'If grass is fairly dry, the growth point can easily break by stepping on, or driving over it. Then recovery is out of the question.’

Grass on sandy soil most at risk

'Dutch grasslands mainly consist of Lolium perenne (ryegrass)', explains Philipsen, 'that is a species with a great recovery ability. One living plant per 10 square centimetres is enough to restore the pasture.’ Lolium perenne roots relatively deep, thus will stay alive longer than other species. Other grass species may have a harder time to survive.

'The soil type is also very important for the recovery capacity of grass,' says Philipsen. "Clay contains a lot of moisture and the groundwater is relatively shallow. Peat soils also contain a lot of water, but can dry out more than clay. Sandy soil gives the most risks. Not only is the groundwater relatively deep, a type of scorch damage can also occur. Then it is as if the shoot is scorched by the sunlight reflecting on the sand.'

How bad is this drought for dairy farming?

According to Philipsen, the feed stock is very large, so few dairy farmers will get into trouble. 'I do not expect any dramatic consequences for the sector,' says Philipsen. However, feed prices will rise as the demand increases.

The drought has greater consequences for the farm management since fewer cows are grazing and less manure is applied. ‘Grass doesn’t need fertilizers now, but before September 1 manure has to be applied, as another winter arrives, and again manure needs to be stored.’ Philipsen thinks that the manure storage capacity can become a bottleneck.

Why farmers are allowed to irrigate

'It seems unfair that some farmers are allowed to irrigate their grass while citizens are not allowed to sprinkle their lawn', says Philipsen. ‘But farmers need to feed their cattle. If their grass is yellowed, they have to purchase feed. They therefore feel the drought directly in their income.'

In addition, farmers use surface water or water from their own wells. Therefore they do not affect the public water grid. If grass dies on sandy soils, it costs a lot of energy to reseed it. 'Which in turn puts an extra burden on the environment.'

If the drought becomes more extreme

In some regions, farmers already are banned to irrigate with surface water. ‘If it gets even more extreme,’ says Phlipsen, ‘there can be irrigation bans which we have never experienced before.’ According to Philipsen, the discussions have already started, for example, in Flevoland, a region which always has enough water. 'But we may also see bans in the river area, and in the western part of the Netherlands.'