Do it now – how to manage your grass once the rain comes.

New Do It Now ImageCurrently across most of the UK, soil is severely moisture deficient. Over 75 mm of rain is needed to return the soil back to field capacity. It has been a very dry June with the July will continue to be dry.

Many farmers are feeding supplements to ensure demand is met while trying to preserve some ground cover. The cover will also shade the ground from the baking heat and help to reduce further moisture loss.  It is important to try and not graze pasture down too low (less than 3cm) as it will take longer to recover when the rain comes.  See Figure 1.

Fig 1 Do It Now

 

When it starts to rain (we are an island on the side of a very big ocean, so it will rain soon), it is important that supplements are maintained to ensure grass has chance to recover. This is likely to be around 21 days to give grass plants chance to push up some leaves and rebuild its root reserves before the leaves are removed by a grazing animal. It could be that you maintain animals on sacrifice fields that may need reseeding or can be allowed to recover later in the year. Grass plants will be vulnerable as they had a poor spring, a rapid growth period and then a dry time, so root reserves will be low.

 

 Figure 1. The impact of grazing too low on recovery time

Currently the lack of moisture is affecting the uptake of nitrogen (N) so there is no value of spreading it, just in case. It is likely that after the first rain, N that has been mineralisation from the soil or not utilised from previous applications will drive the recovery growth but it is likely that additional N will be needed to boost grass production, especially if silage cuts are still required.  Remember that only apply N when soils are moist enough for active growth or N will be lost to the environment. The response rate per kg N may vary from 10-15 kg DM on high-fertility sites - it won’t be as high as in the spring.

Parasites are likely to be a problem once the rain comes as although the dry weather has reduced the parasites available for ingestion, the larvae would have just moved into the soil and are likely to return once there is moisture. Regular monitoring of faecal egg count (if possible) or liveweight gains to ensure parasites are not affecting performance will be important.

It is still worth allocating fields for autumn reseeds based on previous production or percentage of sown species, as situations may chance rapidly.